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Methodologies for the Synthesis of 3,4-Dioxypyrrole-based pi-Conjugated Materials

Permanent Link: http://ufdc.ufl.edu/UFE0043591/00001

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Title: Methodologies for the Synthesis of 3,4-Dioxypyrrole-based pi-Conjugated Materials
Physical Description: 1 online resource (115 p.)
Language: english
Creator: Arroyave, Frank
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2011

Subjects

Subjects / Keywords: cross-coupling -- decarboxylation -- dioxypyrrole
Chemistry -- Dissertations, Academic -- UF
Genre: Chemistry thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Organic pi-conjugated polymers are attractive due to a combination of their electronic properties, relatively low cost production and processability. Due to these features, pi-conjugated materials are envisioned to replace many inorganic materials in various applications. Synthetic methodology plays an important role in the development and understanding of pi-conjugated polymers by allowing the construction of new materials with diverse electronic properties, higher molecular weights and purities. The work presented herein focuses on developing new chemistries for the synthesis of novel pi-conjugated materials-oligomers and polymers-based on the electron rich heterocycle 3,4-dioxypyrrole (XDOP). The work presented in Chapter 2 and 3 describes the efforts to synthesize 3,4-dioxypyrrole-based pi-conjugated molecules, by taking advantage of the inherent ability of 3,4-dioxypyrroles to undergo decarboxylation. Chapter 2 describes how various pi-conjugated molecules based on XDOPs were synthesized via Pd-mediated decarboxylative cross coupling. The optimization of the experimental conditions lead to an efficient cross-coupling reaction for N-alkyl-3,4-propylenedioxypyrroles (ProDOPs), and acceptable to high reaction yields were observed for various ProDOP carboxylates and aryl bromides that were employed. Chapter 3 describes an alternative synthetic methodology towards N-functionalized poly-XDOPs. The method was modified from the previously reported route by Walczak and coworkers. This reaction, a deiodination polycondensation, proved to be a convenient and efficient polymerization procedure for the synthesis of ProDOP-based polymers and oligomers. Chapter 4 describes the synthesis of fused-aromatic diketones and how these molecules can be employed to generate a wide variety of monomers-both donors and acceptors-as potential precursors for the synthesis of new pi-conjugated materials. This work is significant given that access to novel donor and acceptor molecules is vital to generate new pi-conjugated materials with improved physical and electronic properties.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Frank Arroyave.
Thesis: Thesis (Ph.D.)--University of Florida, 2011.
Local: Adviser: Reynolds, John R.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2013-12-31

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Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2011
System ID: UFE0043591:00001

Permanent Link: http://ufdc.ufl.edu/UFE0043591/00001

Material Information

Title: Methodologies for the Synthesis of 3,4-Dioxypyrrole-based pi-Conjugated Materials
Physical Description: 1 online resource (115 p.)
Language: english
Creator: Arroyave, Frank
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2011

Subjects

Subjects / Keywords: cross-coupling -- decarboxylation -- dioxypyrrole
Chemistry -- Dissertations, Academic -- UF
Genre: Chemistry thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Organic pi-conjugated polymers are attractive due to a combination of their electronic properties, relatively low cost production and processability. Due to these features, pi-conjugated materials are envisioned to replace many inorganic materials in various applications. Synthetic methodology plays an important role in the development and understanding of pi-conjugated polymers by allowing the construction of new materials with diverse electronic properties, higher molecular weights and purities. The work presented herein focuses on developing new chemistries for the synthesis of novel pi-conjugated materials-oligomers and polymers-based on the electron rich heterocycle 3,4-dioxypyrrole (XDOP). The work presented in Chapter 2 and 3 describes the efforts to synthesize 3,4-dioxypyrrole-based pi-conjugated molecules, by taking advantage of the inherent ability of 3,4-dioxypyrroles to undergo decarboxylation. Chapter 2 describes how various pi-conjugated molecules based on XDOPs were synthesized via Pd-mediated decarboxylative cross coupling. The optimization of the experimental conditions lead to an efficient cross-coupling reaction for N-alkyl-3,4-propylenedioxypyrroles (ProDOPs), and acceptable to high reaction yields were observed for various ProDOP carboxylates and aryl bromides that were employed. Chapter 3 describes an alternative synthetic methodology towards N-functionalized poly-XDOPs. The method was modified from the previously reported route by Walczak and coworkers. This reaction, a deiodination polycondensation, proved to be a convenient and efficient polymerization procedure for the synthesis of ProDOP-based polymers and oligomers. Chapter 4 describes the synthesis of fused-aromatic diketones and how these molecules can be employed to generate a wide variety of monomers-both donors and acceptors-as potential precursors for the synthesis of new pi-conjugated materials. This work is significant given that access to novel donor and acceptor molecules is vital to generate new pi-conjugated materials with improved physical and electronic properties.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Frank Arroyave.
Thesis: Thesis (Ph.D.)--University of Florida, 2011.
Local: Adviser: Reynolds, John R.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2013-12-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2011
System ID: UFE0043591:00001


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1 METHODOLOGIES FOR THE SYNTHESIS OF 3,4 DIOXYPYRROLE BASED CONJUGATED MATERIALS By FRANK ANTONIO ARROYAVE MONDRAGON A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF TH E REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2011

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2 2011 Frank A. Arroyave Mondragon

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3 To my wife and my f amily

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4 ACKNOWLEDGMENTS I w ould like to thank my advisor Prof John R. Reynolds, for givin g me th e opportunity to join his research group and also for his teachings about sci ence, writing and life He gave me the support, tools and freedom to continue de veloping my scientific thinking and also allow ed me to freely pursue and get involved in v arious aspects of organic synthesis and polymer science I can sincerely say that he is the Ph. D. advisor that every graduate student should have. I would like to thank all the professors who have contributed to my scientific education at the University of Florida In particular, P rof essor Ken Wagener who through his lectures showed me a new level of polymer science. I would like to thank Drs. Svetlana Vasil y eva, and Aubrey Dyer for their teaching s and help in electrochemistry, and Drs. Mike Craig, Lea ndro Estrada, Dan Patel, Chad Amb Ryan Walczak Ken Graham Eric Shen and David Liu for sharing their knowledge through very useful scientific discussions Thanks to Coralie Richard for listening and carrying out my cr azy ideas which in many cases turne d out not to be crazy at all Also, I would like to thank all the Butler lab and Reynolds group members who have made the lab a pleasant and dynamic place to work. I would like to thank Giovanni Rojas and Mariela Rodriguez, Fabio Zuluaga, Paula Delgado, a nd Henry Martinez for their friendship. I would like to thank my wife and my family for their unconditional support and love, since they are the motivation behind my personal and professional achievements And finally thanks God for making everything pos sible

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5 TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................ ................................ ................................ .. 4 LIST OF TABLES ................................ ................................ ................................ ............ 7 LIST OF FIGURES ................................ ................................ ................................ .......... 8 LIST OF SCHEMES ................................ ................................ ................................ ........ 9 ABSTRACT ................................ ................................ ................................ ................... 12 CHAPTER 1 INTRODUCTION ................................ ................................ ................................ .... 14 Conjugated Polymers: History, Synthesis, Properties and Applications ................. 14 Brief History of Conjugated Polymers ................................ ............................. 14 Syntheses of Conjugated Polymers ................................ ............................... 15 Properties and Applications of Conjugated Polymers ................................ ..... 18 Poly D ioxypyrroles (Poly XDOPs) and their Place in the World of Conjugated Polymers ................................ ................................ ................................ ........ 24 2 ORGANOMETALLIC CROSS COUPLING OF DIOXYPYRROLES ....................... 26 Synthesis of 3,4 Dioxypyrroles ................................ ................................ ............... 26 Palladium Mediated Cross Coupling of 3,4 Dioxypyrroles ................................ ...... 26 Suzuki Cross Coupling ................................ ................................ ................... 26 Pd mediated Decarboxylative Cross Coupling ................................ ............... 28 Experimental Section ................................ ................................ .............................. 41 General Information ................................ ................................ ........................ 41 Experimental Procedures ................................ ................................ ............... 42 3 SYNTHESIS OF DIOXYPYRROLE BASED POLYMERS VIA DEHALOGENATION POLYCONDENSATI ON ................................ ....................... 67 Dehalogenation Polycondensation ................................ ................................ ......... 67 General Stability of 3,4 Dioxypyroles ................................ ................................ ...... 75 Experimental Section ................................ ................................ .............................. 77 General Information ................................ ................................ ........................ 77 Experimental Procedures ................................ ................................ ............... 78 4 FUSED AROMATIC DIKETONES AS PRECURSORS FOR THE SYNTHESES OF CONJUGATED MATERIALS ................................ ................................ ............ 83 Syntheses of Fused Aromatic Diketones ................................ ................................ 84

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6 Synthesis of Benzo[1,2 b:6,5 b']dithiophene 4,5 dione (BDTD) ..................... 84 Synthesis of 3,8 Dibromo 1,10 phenanthroline 5,6 dione and 2,7 Dibromophenanthrene 9,10 dione ................................ ....................... 88 Synthesis of 2,7 Dibromophenanthrene 9,10 dione ................................ ....... 89 Synthesis of Acceptor Molecules ................................ ................................ ............ 89 Synthesis of Phenanthro[9,10 d]oxazole ................................ ........................ 89 Synthesis of Dithieno[3',2':3,4;2'',3'':5,6]benzo[1,2 c][1,2,5]thiadiazole (DT BTD) and Dithieno[3',2':3,4;2'',3'':5,6]benzo[1,2 c]f urazan (DTBF) ...... 90 Reactivity of Br 2 DTBF in the Stille Coupling ................................ .................. 94 Reductive Etherification of Aromatizable Diketones ................................ ............... 95 Experimental Section ................................ ................................ .............................. 95 General Information ................................ ................................ ........................ 95 Experimental Procedures ................................ ................................ ............... 96 5 PERSPECTIVE AND OUTLOOK ................................ ................................ .......... 108 LIST OF REFERENCES ................................ ................................ ............................. 111 BIOGRAPHI CAL SKETCH ................................ ................................ .......................... 115

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7 LIST OF TABLES Table page 2 1 Various decarboxylative experiments for compounds 9, 10 and 1 .................... 31 3 1 Polymerization of various ProDOP dicarboxylic acids via dehalogenation polycondensation using N halosuccinimides. ................................ ..................... 71 3 2 Polymerization of various ProDOP dicarbox ylic acids via dehalogenation polycondensation using various halogen sources. ................................ ............. 72

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8 LIST OF FIGURES Figure page 1 1 Chemical structures for polyanili ne (PANI), polypyrrole (PPy), and polyacetylene ( cis and trans ). ................................ ................................ ........... 14 1 2 Evolution of the energy band gap in polypyrrole ................................ ................. 20 1 3 Evolution of the energy band gap in polyacetylene ................................ ............ 22 1 4 Uv Vis NIR of pristine and various levels of doping of a poly ProDOP N EtHx solution in DCM. ................................ ................................ ................................ 23 2 1 Various ProDOP based conjugated molecules synthesized by Pd mediated decarboxylative cross coupling. ................................ ................................ .......... 34 3 1 Proton NMR monitoring of the degree of conversion of a ProDOP monoacid using NIS in DCCl 3 ................................ ................................ ............................ 70 3 2 Solution doping of polymer 44a Using NOPF 6 [3mM] in DCM, and CVs of the same polymer spray cast onto ITO coated glass ................................ ............... 75 4 1 Proposed BDTDHCl adduct ................................ ................................ ............... 87

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9 LIST OF SCHEMES Scheme page 1 1 Various synthetic routes to ward poly( p phenylene vinylene), PPV. .................... 16 2 1 Synthetic routes to XDOPs. ................................ ................................ ................ 26 2 2 Borylation and stannylation of two ProDOP based m olecules. ........................... 27 2 3 Suzuki cross coupling of a ProDOP based molecule. ................................ ........ 28 2 4 Pd mediated decarboxylative cross couplings according to Gooen et al. 44 and Bilodeau et al. ................................ ................................ ............................. 30 2 5 Initial attempts to apply the Pd mediated decarboxylative cross coupling to ProDOP based molecules. ................................ ................................ ................. 30 2 6 Proposed sequential decarboxylation of 9 and direct arylation of 1 to explain the low yield in the decarboxylative cross coupling. ................................ ........... 32 2 7 General decarboxylative cro ss coupling using the potassium carboxylate 10 ... 33 2 8 Pd mediated decarboxylative cross coupling under aqueous reaction conditions. ................................ ................................ ................................ .......... 36 2 9 Failed attempt to apply the Pd mediated decarboxylative cross coupling to a ProDOP dicarboxylic acid. ................................ ................................ .................. 36 2 10 Syntheses and decarboxylation of three different ProDOP acids. ...................... 37 2 11 Pd mediated decarboxylative cross couplings on a ProDOP dicarboxylic acid and a potassium ProDOP dicarboxylate. ................................ ............................ 39 2 12 Pd medi ated decarboxylative cross couplings on two potassium ProDOP dicarboxylate oligomers. ................................ ................................ ..................... 39 2 13 Synthesis of a BTD based oligomer via decarboxylative cross coupling. ........... 40 2 14 Decarboxylative cross coupling using a ProDOP diester. ................................ ... 41 2 15 Synthesis of ProDOP esters and acids. ................................ .............................. 43 2 16 General procedure 1: decarboxylative cross coupling using the potassium carboxylate 10 ................................ ................................ ............................... 48 2 17 General procedure 2: decarboxylative cross coupling of compound 9 us ing potassium carbonate as base. ................................ ................................ ............ 50

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10 2 18 General procedure 3: decarboxylative cross coupling using compound 9 in toluene/water ................................ ................................ .............................. 51 2 19 Decarboxylative cross coupling of ProDOP monoacid 9 with BTD based molecules using potassium bicarbonate. ................................ ............................ 57 2 20 Decarboxylative cross coupling of ProDOP diacid 24 using potassium c arbonate and tetra( n butyl)ammonium bromide. ................................ ............... 59 2 21 Decarboxylative cross coupling using the ProDOP dicarboxylate salt 29 ......... 60 2 22 Decarboxylative cross coupling using the potassium ProDOP dicarboxylate salts 30 and 31 ................................ ................................ ...................... 62 2 23 Decarboxylative cross coupling using the ProDOP monoacid 27 and 4,7 dibromobenzo[c][1,2 ,5]thiadiazole. ................................ ................................ ..... 65 3 1 Synthesis and polymerization of 2,5 diodo 3,4 dioxypyrroles previously reported by Walczak et al. 23 ................................ ................................ .............. 67 3 2 Polymerization attempt for a ProDOP based oligomer using the triiodide route ................................ ................................ ................................ ........... 68 3 3 Halodecarboxylation and halogenation of two 3,4 propylenedioxypyrroles using N halosuccinimides. ................................ ................................ .................. 69 3 4 In situ halo decarboxylation and dehalo polycondensation of the oligomeric mixture 41a c ................................ ................................ ................................ ..... 70 3 5 Halo decarboxylation of the p otassium ProDOP carboxylate 13 using iodine. ... 71 3 6 Post polymerization of the polymer 44a in dibromomethane. ............................. 74 3 7 Unexpected oxidation of a ProDOP based molecule. ................................ ......... 76 3 8 Proposed mechanism for the oxidation of a ProDOP based molecule. .............. 76 4 1 Various mol ecules that can be synthesized from fused aromatic diketones. ...... 83 4 2 Failed synthesis of Br 2 BDTD via Friedel Crafts acylation. ................................ 85 4 3 Alternative route towards BDTD. ................................ ................................ ........ 85 4 4 Two step synthesis of BDTD ................................ ................................ .............. 86 4 5 Bromination of BDTD. ................................ ................................ ......................... 88 4 6 Synthesis of 3,8 dibromo 1,10 phenanthroline 5,6 dione ................................ ... 88

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11 4 7 Synthesis of 2,7 dibromophenanthrene 9,10 dione ................................ ............ 89 4 8 Unexpected synthesis of phenanthro[9,10 d]oxazole ................................ ......... 90 4 9 Synthesis of Br 2 DT BTD. ................................ ................................ ................... 90 4 10 Synth esis of Br 2 DTBF. ................................ ................................ ....................... 91 4 11 Proposed mechanistic path for formation of DTBF. ................................ ............ 91 4 12 Synthesis of Br 2 DTBF from Br 2 BDTD. ................................ .............................. 92 4 13 Synthesis of D TBF and DT BDT from the dioxime ................................ ............ 92 4 14 Failed reduction of DTBF under various relatively mild reaction condition s. ....... 93 4 15 Reduction of Br 2 BTD, using cesium carbonate in NMP. ................................ .... 93 4 16 Unexpected cleavage of Br 2 DTBF, using cesium carbonate in NMP. ............... 93 4 17 Model Stille reaction for Br 2 DTBF. ................................ ................................ ..... 94 4 18 Random Stille co polymerization for Br 2 DTS, (Me 3 Sn) 2 DTS and Br 2 DT BF. .... 94 4 19 Reductive etherification of aromatizable diketones ................................ ............. 95

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12 Abstract of Dissertation Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy METHODOLOGIES FOR THE SYNT HESIS OF 3,4 DIOXYPYRROLE BASED CONJUGATED MATERIALS By Frank A. Arroyave December 2011 Chair: John R. Reynolds Major: Chemistry O rganic conjugated polymers are attractive due to a combination of their electronic properties, relative ly low cos t production and processability D ue to these features conjugated materials are envisioned to replace many inorganic material s in various applications Synthetic methodology play s an important role in the development and understanding of conjugated polymers by allowing the construction of new materials with diverse electronic properties, higher molecular weights and purities The work p resented herein focuses on developing new chemistries for the synthesis of novel conjugated materials oligomers and polymers based on the electron rich heterocycle 3,4 dioxypyrrole (XDOP) T he work presented in Chapter 2 and 3 describe s the efforts to s ynthesize 3,4 dioxypyrrole based conjugated molecules by taking advantage of the inherent ability of 3,4 dioxypyrroles to undergo decarboxylat ion Chapter 2 describes how v arious conjugated molecules based on XDOPs were synthesized via Pd mediated de carboxylative cross coupling The optimization of the experimental conditions lead to an efficient cross coupling reaction for N alkyl 3,4

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13 propylenedioxypyrroles (ProDOP s ) and a cceptable to high reaction yields were observed for various Pro DOP carboxylat es and aryl bromides that were employed Chapter 3 describes a n alternative synthetic methodology towards N functionalized poly XDOPs T he method was modified from the previously reported route by Walczak and coworkers This reaction, a deiodination po lycondensation proved to be a convenient and efficient polymerization procedure for the synthesis of ProDO P based polymers and oligomers. Chapter 4 describes the synthesis of fused aromatic diketones and how these molecules can be employed to generate a w ide variety of monomers both donor s and acceptors as potential precursors for the synthesis of new conjugated materials This work is significant given that access to novel donor and acceptor molecules is vital to generate new conjugated materials wit h improved physical and electronic properties

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14 CHAPTER 1 INTRODUCTION Conjugated Polymers: History, Synthesis, Properties and Applications Brief History of Conjugated Polymers The first synthetic appearance of a conjugated polymer in a laboratory can be traced to the 19 th century I nterestingly at that time scientist s did not know about the existence of polymers or macromolecules and the general knowledge of organic chemistry was quite limited Three of the most important representatives of these mate rials, p olyaniline (PANI), p olypyrrole (PPy), and p olyacetylene shown in Figure 1 1, were the first conjugated polymers to be synthesized I n 1862 Henry Letheby reported the anodic polymerization and the electrochromic properties of polyaniline a blue el ectrochromic material; 1 a similar observation was previously made under chemical oxidation in acidic media by Runge in 1834 and Fritzsche in 1840. 2 Figure 1 1 Chemical structures for polyaniline (PANI), polypyrrole (PPy), and p olyacetylene ( cis and trans ). In 1963, Weiss and coworkers r eported the synthesis of iodide doped p olypyrrole prepared via deiodo polycondensation T he material produced by this method had conductivities of ~1 S/cm 3 5 and in 1968 D et al. also reported the synthesis of olypyrrole was called at that time, via electrolysis of pyrrole in dilute sulfuric acid 6 U nfortunat ely report s on conducting polypyrrole remained unnoticed for several decades Polyacetylene on the other hand, had a more

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15 fruitful history: i n 1953 and 1954 Ziegler and N atta developed new organometallic catalytic systems for the polymerization of polyolefins T his method had a high impact on polymer science and industry culminating with Ziegler and Natta being awarded the Nobel prize in Chemistry in 1963. 7 9 Natta and co workers used this methodology in 1958 to prepare p olyacetylene (a semiconductor) 10 and this methodology was further exploited by several research groups in the area of material s science s 11 13 I n 1977 Shirakawa, Heeger and Ma cDia rmi d collaborated to prepare and study p olyacetylene by u sing the Ziegler Natta methodology and their knowledge about the doping of semiconductor s obtaining high conductivities (~10 3 S/cm) on halog en doped p olyacetylene 14 This achievement was a significant breakthrough which launched the field of conducting polymers 15 So far due to its low stability and processability, polyacetylene has yet to find practical applicability. Nevertheless, polyacetylene laid the groundwork for the study and under standing of conjugated polymers and the basic polyacetylene structure is a common motif i n many polymers today 16 Syntheses of Conjugated P olymers Synthetic methodology has played an important role in the development of conjugated polymers; in fact, the understanding of conjugated polymers has adv ance d in parallel with new methods of synthesis, which have al low ed th e construction of materials with higher molecular weights and purities Pyrolysis and c hemical or electrochemical oxidation were commonly used by researchers during the initial efforts to produce conjugated polymers U nfortunately, these methods often produced insoluble products, and it was not possible to obtain reliable structural information about the polymer s N ew synthetic development s led to numerous methods

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16 to produce conjugated polymers not only with the desired physical and electronic f eatures but also with high processability Chemical or electrochemical oxidation is still used for the synthesis of various conjugated polymers, but this methodology is mainly restricted to a few monomers and commonly only used to acquire preliminary data o n a specific conjugated monomer or polymer I n many cases, chemical or electrochemical oxidation has been replaced by other synthetic methods in particular organometallic cross couplings, possessing a broader scope In general the methodology to be ut ilized depends on the polymeric systems being synthesize d Scheme 1 1 Various synt hetic routes toward p oly ( p phenylene v inylene), PPV. A clear example of the different strategies employed to synthesize a particular type of polymer is shown in Scheme 1 1 This scheme shows various methods employed to produce poly ( p phenylene vinylene), PPV, a material studied for various applications, such as light emitting diodes (LED) and photovoltaic devices. 17,18 The m ost common

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17 path ways towards the synthes i s of PPV s involve the reaction of a functionalized para xyl ene derivative with base to generate a qu inodimethane intermediate which then polymerizes to for m a pre polymer Typically, t h e pre polymer is then transformed into PPV by heating under reduced pressure The predominant quinodimethane routes include Wessling Zimmerman, Vanderzand e, and Gilch 17,18 The Wessling Zimmerman method uses sulfonium salts as leaving groups ; due to the unpleasant odors however as well as the toxic byproduct s this route is typically avoided T he Vanderzand e group developed a variant of the Wessling Zimmerman method (not shown in S cheme 1 1 ) T h is method combine s a halide with a sulfinyl leaving group (Y = Cl and SOR) in the same molecule Although, the monomer synthesis is longer and less efficient than in the Wessling Zimmerman method, t his method produces higher quality PPV s A nother method is t he Gilch route, which makes use of halide leaving groups This method is now the most widely used for making soluble PPVs In this case, it is also possible to isolate the halide precursor ( pre polymer) to convert it to the final conjugated material by thermal treatment under vacuum or using an excess of base. The quinodimethane methods describe d can be only employed for making homopolymers or random copolymers There are d irect routes that allow the synthesis of copolymers with two different alternating arylene moieties, and these direct routes avoid the formation of defects that are frequently seen in the quinodimethane routes M olecular weights obtained by these direct routes are typically lower than those obtained by the pre polymer routes D irect routes include Schrock metathesis (ROMP), Heck coupling, and McMurry, Knoevenagel, Wittig and Horner polycondensations shown in Scheme 1 1

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18 The physical and electronic properties of PPV based material s depend highly on the stereochemistry of the double bonds ( cis or trans ), and the R and X groups I n some cases the final conjugated polymer has limited solubility but since some of these methods produce pre polymers that have higher solubility than the final PPV, processing of the pre polymer circumvents the need to handle PPV It is noteworthy that PPVs can be seen as polyacetylene derivative s since they contain the basic poly acetylenic structure in their backbone s Thus, PPVs contain many of the same attractive electronic properties as polyacetylene while also having considerably higher stability and processability Properties and Application s of Conjugated P olymers Many uses have been envisioned for conjugated polymers, especially since the discovery of their conducting properties particularly as materials that could potentially replace inorganic materials in various electronic applications Two o f the most attracti ve characteristics of conjugated polymers are their relative ly low production cost s and their processability Some of the applications that have been envisioned for conjugated polymers include solar cells, thermoelectrics, elec trodes, displays, supercapacitors, batteries, sensors, and antistatic agents The applications of a particular polymer depend on various factors, such as electronic band gap conductivity HOMO and LUMO energy levels, processability and stability among ot hers 16 Typically, conjugated polymers are insulators or semiconductors with low conductivities and an intrinsically organic conducting conjugated polymer has not yet been developed The semiconductor behavior comes from the separation between the valence band (VB) and t he conduction band (CB), which is too big to allow the

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19 movement of electrons from one band to another. All the polymers shown in Figure 1 1 are semiconductors, but on ce the conjugated polymer s are doped typically by removal of electrons using an oxidizing agent such as iodine the conductivities can drama tically increase up to several hundreds S/cm ( up to several kS/cm for polyacetylene) and in some cases, with values comparable to the conductivity in metals Band gaps ( E g ) which is the energy differenc e between the valence band (VB) and the conduction band (CB) in polymers depend heavily on the physical and electronic properties of the polymer backbone as well as the degree of polymerization ( X n ), which is the number of repeat units in the polymers. The evolution of the band gap ( E g ) with increasing X n and the effect s of chemical doping in poly pyrrole are shown in F igure 1 2 Figure 1 2 (left) shows how the orbital s in poly pyrrole evolve as the number of monomeric units in the chain increase s As X n increases to an effective conjugation length (not necessarily to ) the orbital distribution gap rea ches a thresho ld value called the band gap ( E g ) Typically, band gaps for organic conjugated polymers fall between 1 3 eV, and al though there is a high electron delocalization due to the long conjugated system, the difference in energy between the VB and the CB ( E g ) is too high and does not allow the material to behave as a conducting material i. e. the thermal energy is not enough to move an ele ctron from the VB to the CB; therefore, these materials behave as semiconductors The main reason why the E g of organic conjugated material does not reach values close to zero as X n tends to is due to the bond length alternation in the polymer backbon e also known as Peierl s distortion 19 which states that 1D lattices with filled (and indeed, f illed ) bands are susceptible to distort in a way that permi ts the opening

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20 of a gap at the Fermi energy level, resulting in a decrease in the energy of the system and an increase in the stability of the system C onjugated organic material s can be seen as quasi one dimensional periodic lattices, and therefore are susceptible to Peierls distortion. Figure 1 2. E volution of the energy band gap in polypyrrole, from th e monomer to the polymer (left ), and from the neutral polymer t o the p doped polymer (right ). For clarity purposes e lectrons in the VB were omitted, and counter ions are not shown in the doped polymers Adapted from: Synthetic Metals 1998 96, 177 189 20 and Phys. Rev. B 1982, 26, 5843. 21 To illustrate how polarons and bipolarons are formed in conjugated polymers, we can consider a n example of a film of poly pyrrole in the presence of an oxidant such as iodine, represented as X 2 in Figure 1 2 As the doping proc ess start s one or more electrons are extracted from the conjugated polymer which generates a radical cation, called a polaron (see Figure 1 2) I n a polaron, the radical and the cation are paired by resonance, and two new energy levels are generated i n the gap (SOMO and LUMO) with one of these energy levels occupied by an unpaired electron (SOMO) 21,22 Two polarons can combine to form a bipolaron, with the two radical species forming a double bond, leaving behind two cations ; these two cations are also associated by E g VB CB Doping Polymerization Polaron Bipolaron Bipolaron Bands 2k X k X 2

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21 resonance and the separation between them can vary depending on the conjugated polymer typically, 3 5 rings for pol y pyrrole Upon increase the doping level new bipolarons are formed in the same polymer chain and in o ther polymer chains in the film leading to two bipolaronic bands At high doping level s these two bands can merge. For poly dioxypyrrole s and many oth er doped conjugated materials, polarons and bipolarons are the main species responsible for charge transport (conductivity) ; but for trans polyacetylene the mechanism is slightly different trans p olyacetylene is unique among conducting polymers because it possesses a degenerate ground state i e., two geometric structures corresponding exactly to the same total energy, and t he two structures differ from one another by the exchange of the carbon carbon single and double bonds Due to this degeneracy, tw o polaron s instead of forming a bipolaron, can readily separate in the polymer chain without being associated with each other forming two solitons T his process is favored since the geometric structure that appears between the two charges has the same e nergy as the geometric structure on the other sides of the charges thus, there is no in crease in distortion energy if the two charges se parate. 21 The appearance of a soliton leads to the formation of a new energy level in the middle of the electronic gap as shown in Figure 1 3 and an i ncrease in the doping level leads to the formation of a soliton band, which can also serve as the conduction band Solitons can be positive, neutral or negative, and as previously mentioned, their formation does not occur in poly pyrrole and is only observ ed in conjugated materials with a degenerate ground state such as poly acetylene

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22 At a ny given moment and even a t high doping levels it is possible to have polaron s bipolaron s and solitons in the same polymeric material but t he formation of soliton a nd bi polaron bands are the two main phenomena responsible for conduction in doped conjugated polymers which allow electrons (e ) or holes (h + ) to move along ( by resonance) and between ( by ho p ping ) the polymer chains; emulating the conductivity in metals where the separation between VB and CB is minimum or does not exist It is noteworthy that doping in conjugated polymers can also be achieved upon exposure to light and electrochemically and that most of the charge density (>90%) is typically located close to the counter ion (for clarity the counter ions are omitted in Figure s 1 2 and 1 3 ). Figure 1 3 Evolution of the energy band gap in polyacetylene, from the neutral polymer (left) to the p doped polymer (right) For clarity purposes electrons in the VB were omitted, and counter ions are not shown in the doped polymers Adapted from: Phys. Rev. B 1982, 26, 5843. 21 As was mentioned before, at any given moment it is possible to have polarons bipolarons and solitons in the same polymeric material which can be confirmed by diff erent techniques, such as ESR (electron spin resonance) and absorption spectroscopy Figure 1 4 shows the doping process using NOPF 6 for a pyrrole based polymer, poly ProDOP N EtHx [ poly (propyelene 3,4 dioxy)pyrrole N EthylHexyl ] 23 which has a high optical band gap ( ~ 3.1 eV onset shown at = 400 nm as a dashed gray line )

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23 Figure 1 4 Uv Vis NIR of pristine (black line) and various levels of doping (colored lines) of a poly ProDOP N EtHx solution in DCM, using N OPF 6 as dopant Arrows indicate the evolution of the absorbance spectra for each region upon doping : a hypochromic shift for the transition from neutral to doped in the UV region, and hyperchromic shift for the same transition in the near infrared Color change of the solution, from neutral to doped, is also shown on the right side of the spectrum Adapted from: 23 Macromolecules 2008, 41, (3), 691 700. The black line in Figure 1 4 represents the optical absorpti on of the pri stine solution, which only absorbs in the ultraviolet (Uv) region ( max ~ 315 nm) but once various aliquots of the dopant are added (NOPF 6 ) a hypochromic shift is obse rved for this absorption, but the opposite occurs in the visible (Vis) reg ion, where the absorption corresponding to the radical cations (polarons) emerges as a hyperchromic shift Once the level of doping is increased the bipolaronic absorptions can be also observed as hyperchromic shifts but these abs orb in a lower energy r egion, which correspond to the near infrared (NIR) Due to its high band gap, poly ProDOP N EtHx is colorless, but upon doping, a color change can be observed: red due to the polaronic absorption and green due to the combination of the polaronic and bipol aronic absorptions as shown in F igure 1 3 for the polymer solution in dichloromethane (DCM)

PAGE 24

24 Poly D ioxypyrroles ( Poly XDOPs) and their Place in the World of Conjugated Polymers Poly d ioxypyrroles ( p oly XDOPs) are pyrrole based materials which display ou tstanding properties. 24 Poly XDOPs inherit most of the ir properties from polypyrrole, and circumvent some of its drawbacks crosslink during polymerizati on and its low processability This can easily be explain ed since th e substitution with alkoxy groups on the 3 and 4 positions o f the pyrrole ring avoids crosslinking during the polymerization simultaneously increas ing the material processability Polym eric materials based on pyrrole and 3,4 dioxypyrrole molecules ( poly XDOPs) possess characteristic optical and electrochemical properties; such as high conductivity, multicolor cathodic and anodic electrochromism, rapid redox switching, and stability to bi o reductants. 17,24,25 These outstanding properties make XDOP based materials excellent candidates for various applications such as sensors, supercapacitors, and electrochromic devices where high conductivity and processability are needed. 24 The polymer previously sho wn in Figure 1 4 can be used to explain some of XDOP s properties P oly ProDOP N EtHx has a high band gap, d ue to the low degree of conjugation between the monomeric units, and this is caused by the repulsion between the alkyl chains (propylene and 2 ethylhexyl) on adjacent pyrrole rings, which h inders the two pyrrole rings from adopting a planar and more conjugated conformation; a s a consequence, most N alkyl dioxypyrroles are colorless or pale yellow in their neutral state Some of the poly XDOP s properties, such as solubility and electronic band gaps, can be finely adjusted by including different functional groups by N or O

PAGE 25

25 su bstitution of the XDOP monomers The syntheses and prope rties of a wide variety of XDOP monomer have been reported. 24,26 29 The work presented in this dissertation focuses on developing new chemistries for the synt hesis of novel conjugated materials oligomers and polymers based on the electron rich heterocycle 3,4 dioxypyrrole (XDOP) The work presented in Chapter 2 and 3 describes the efforts to synthesize 3,4 dioxypyrrole based conjugated molecules via the Pd mediated decarboxylative cross coupling, and the deiodination polycondensation B oth methodologies proved to be convenient and efficient methods for the synthesis of ProDOP based polymers and oligomers. Chapter 4 describes the synthesis of fused aromatic diketones and how these molecules can be employed to generate a wide variety of monomers donor s and acceptors as potential precursors for the synthesis of new conjugated materials This work attempts to provide new building blocks that ca n be combined with other available molecules to produce new materials with higher charge mobilities and unique electronic band gaps two important elements in a conjugated polymer

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26 CHAPTER 2 ORGANOMETALLIC CROSS COUPLING OF DIOXYPYR ROLES Synthesis of 3,4 Dioxypyrro les Although some 3,4 dioxypyrrole (XDOPs) derivatives are commercially available the custom sy nthes i s of these materials are preferred due to the low cost of the precursors and relatively easy scalability of the chemical reactions XDOPs can be synthe sized by a variety of methodologies, for example, via Hinsberg condensation from acyclic starting materials 24,30,31 as shown in routes A and B in Scheme 2 1 and also from the heterocyclic starting material 3,4 dih ydroxy 2,5 dimethoxytetrahydrofuran via route C It is noteworthy that the decarboxylation of the XDOP dicarboxylic acids is carried out in the last step in routes A and B and as will be described later, this tendency of XDOPs to decarboxylate can be ex ploit ed in different ways to produce XDOP based materials. Scheme 2 1 Synthetic routes to XDOPs Palladium Mediated Cross Coupling of 3,4 Dioxypyrroles Suzuki Cross Coupling Nowadays, organometallic cross coupling is th e most common tool employed to synthesize conjugated oligomers and polymers Unfortunately, organometallic coupling is almost unknown for the synthesis XDOPs ; apart from a report by Merz et al 32 literature reports of organometallic coupling of XDOPs are unfamiliar H ence, t he

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27 chemistry presented in this section will describe v ariou s synthetic approaches that allow ed us to produce a variety o f conjugated molecules based on XDOPs via organometallic cross coupling H alo derivatives can be seen as the natural precursors for many organometallic coupling reactions Unfortunately, h alo XDOP derivatives tend to decompose, dimerize, or polymerize, 23,32 and as a result handling and storage of 2,5 dihaloXDOP can be problematic, hindering their utility in organometallic cross couplings Due to the co mplications when 2,5 dihaloXDOP derivatives are employed other approaches were necessary in order to combine the XDOP moiety with other conjugated systems Scheme 2 2 shows two approaches that can be employed to overcome the use of 2,5 dihaloXDOP s Scheme 2 2. Bory lation and stannylation of two ProDOP based molecules. The approaches shown in Scheme 2 2 avoid the usage of halo XDOPs by producing the organometallic reagent using iridium chemistry or n butyllithium Co mpounds 1 and 3 can be made by saponification and further decarboxylation of the

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28 respective diesters T hese compounds can then be subjected to direct borylation 33 using [Ir(OMe)(COD)] 2 and stannylation 34,35 (in t he case of compound 3 ) Compound 2 was isolated in high yield and purified easily, but compounds 4 and 5 were isolated in low yields, and starting material ( compound 3 ) as well as mono substituted products were also present in the reaction crude T hese compounds can only be purified by HPLC since they decompose on silica or alumina although high vacuum distillation may be used if shorter alkyl chains than C 12 H 25 are employed The boronic ester 2 was employed in the Suzuki coupling (Scheme 2 3) which produced compound 6 in high yield demonstrating that the Suzuki coupling can be carried out on XDOP boronate esters in high yields Scheme 2 3. Suzuki cross coupling of a ProDOP based molecule. Pd mediated Decarboxylat ive Cross C oupling As was mentioned before, if the Hinsberg condensation is employed to make XDOPs routes A and B then two carboxylic acids will be present in the XDOP molecule, which have to be removed by decarboxylation to produce the 2,5 unsubstitut ed XDOP The 2,5 unsubstituted XDOPs can then be functionalized to react with other conjugated molecules to form more complex conjugated systems as was shown for the Suzuki cross coupling Another alternative route is to employ those carboxylates to generate the new conjugated molecules via palladium mediated decarboxylative cross coupling.

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29 The p alladium mediated decarboxylative cross coupling was recently developed by various research groups, and t his methodology provides a convenient alternative to traditional cross couplings However, this type of reaction can be only applied in a few cases whe n the molecul ar properties and structure allow it. 36,37 In t he first decarboxylative coupling report ed a copper catalyzed Ullmann like cross coupling was performed by Nilsson in 1966, 38 but remained almost unknown until few year s ago In 1997 Steglich and coworkers 39 41 and more recently Myers et al in 2002, 42 Bilod eau and Forgione et al. in 2006, 43 Gooen et al. in 2006 44 and Lee et al. in 2008 45 reported new effective variants of this methodology using palladium catalysts report differed from previous reports in its use of a cooper catalyst as the transmetallating agent Gooen and coworkers synthesized a variety of biaryls and applied the method in the large scale production of an intermediate of the agricultural fungicide Boscalid Le e an one pot synthesis of unsymmetrical diarylalkynes by a one pot Pd mediated Sonogashira reaction and a decarboxylative coupling using a propiolic acid as substrate. Scheme 2 4 shows the two m ost suitable decarboxylative cross coupling routes for 5 member ring heteroaromatics ; these two reactions were described by Goo en et al. 44 and by Bilodeau and coworkers 43 in 2006 As was mentioned before, the decarboxylation of the 3,4 dialkyldioxypyrrole dicarboxylic acids is carried out in the last step in two of the synthetic routes described in Scheme 2 1 (routes A and B) thus, it was conceivable that this tendency of XDOPs to decarboxylate could be exploited to

PAGE 30

30 produce XDOP based materials via decarboxylative cross couplings by e mploying any of the routes presented in Scheme 2 4. Scheme 2 4. Pd mediated decarboxylative cross couplings according to Gooen et al., 44 and Bilodeau et al.. 43 Unfortunately, both reaction conditions were ineffective for cross coupling of the 3,4 propylenedioxy pyrrole (ProDOP) 9 with arylbromides and as shown in Scheme 2 5 compound 1 was typically received as major or only product (Scheme 2 5 ) ; the desired compound 6 formed in low yield 5 20 % even when anhydrous potassiu m carboxylate 1 0 was also used to assure anhydrous conditions Other bases were also employed (LiH, Cs 2 CO 3 K 2 CO 3 ), and r eaction t emperature was also manipulated; y et no improvement of reaction yields was achieved Sche me 2 5. Initial attempts to apply the Pd mediated decarboxylative cross coupling to ProDOP based molecules.

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31 It was observed that if the amount of transmetallating agent (CuI/phenanthroline) was decreased when Goo or if t he temperature was decreased (150 1 80 ) employed an increase in the reaction yield was achieved (25 50%). A ssuming that the activity of the copper catalyst was too high, t he reactivity of the copper salt was then decreased by adding KBr, 46 for Goo did not result in any visible improvement Table 2 1 Various decarboxylative experiments for compounds 9 10 and 1 entry compound substrate reaction conditions product yield (%) 1 9 none Melt, 123 1 > 99 2 9 none 2 mol% Pd(acac) 2 4 mol% P(o tolyl) 3 NMP, 95C, 24 h. 1 > 99 3 10 none 2 mol% Pd(acac) 2 4 mol% P( o tolyl) 3 NMP, 95C, 24 h. 1 93 4 10 none 10 mol% CuI, 10 mol%, 1,10 phenantroline, 100C, 24 h. 1 97 5 10 none NMP, 105C, 36 h none 6 1 K 2 CO 3, 2 mol% Pd(acac) 2 4 mol% P( o tolyl) 3 NMP, 95C, 48 h. 6 21 Various experiments were carried out to understand some of the initial results. Thermogravimetric analysis (TGA) was used to measure the d ecarboxylation

PAGE 32

32 temperature for 9 (entry 1, Table 2 1), and it was found that the decarboxylation temperature in the molten solid for this compound ( 9 T his temperature was in the range of the temperatures employed to run the reactions in the presence of the palladium catalyst and copper iodide, and lower than the temperatures used when no copper iodide was employed. Reacti ons in entries 2 and 3 (Table 2 1) showed that Pd(acac)/P( o tolyl) 3 was able to decarboxylate 9 and also the anhydrous potassium salt 10 in N methylpyrrolidone (NMP) producing 1 CuI/phenanthroline (the tra n smetallating agent in the cross coupli ng) produced analogous results (entry 4). The experiment in entry 5 showed that potassium salt 10 does not decompose or react under the same conditions used in entries 2 4 in the absence of palladium or copper catalysts, showing relatively stability. Scheme 2 6. Proposed sequential decarboxylation of 9 and direct arylation of 1 to explain the low yield in the initial attempts for the cross coupling of 9 with p dibromobenzene. Surprisingly, it was also found that Pd(acac) 2 /( o tolyl) 3 P/K 2 CO 3 produced the desired product 6 from 1 (entry 6, Table 2 1) in 21% yield at the same temperature used for the decarboxylative coupling This latest result explained the initial results using CuI/Phen/Pd(acac) 2 meaning that under the se conditions, the reaction yields for

PAGE 33

33 9, or its carboxylate salt 10, fit with a direct arylation mechanism 47 or a Heck type reaction 37 on compound 1 which forms relatively fast in the reaction via protodecarboxylation at high temperatures or when Cu(I) is present as shown in Scheme 2 6 Having in mind that the copper(I) catalyst and the high temperature were causing the decom position of the ProDOP carboxylate, the reaction was carried out without copper(I) catalyst, and the temperature was gradually increased from room temperature until product formation was observed P roduct 6 is highly fluorescent under UV light, so its for mation was easily confirmed by UV illumination of the reaction. This was not possible w hen Cu(I) was present since the copper salt quenched the fluorescence The optimization of the reaction lead to the conclusion that the use of a phosphine ligand and P d(acac) in NMP with temperatures between 85 to 110 avoids the undesired protodecarboxylation and can produce high reaction yields for the ProDOP carboxylate 10 (Scheme 2 7) via decarboxylative cross coupling It is noteworthy tha t t he reaction presente d in Scheme 2 7 does not proceed under 85 for compound 10 Scheme 2 7 General decarboxylative c ross coupling using the potassium carboxylate 10 The structure, yield, and temperature employed for various molecules synth esized using the decarboxylative cross coupling of 10 are presented in Figure 2 1 The methodology was quite effective for several aryl dibromides that w ere employed and acceptable to h igh yields with relatively low catalyst load (less than 2 mol % ) were

PAGE 34

34 obtained Relative ly low temperatures were used (85 110 C ) and the optimal reaction temperature varied for each aryl dibromides The reaction times spanned from 6 to 48 hours and s ince there is no n eed for a copper(I) catalyst low or no side products were observed; furthermore, the reaction was no t sensitive towards the presence of water Figure 2 1. Various ProDOP based conjugated molecules synthesized by Pd mediated decarboxylative cross coupling. The method wa s also applied to produce conjugated oligomers containing the benzo[c][1,2,5]thiadiazole (BTD) unit (compounds 22 and 23 Figure 2 1 ) The ability to incorporate this moiety was significant since i nclusion of the BTD unit in a conjugated molecule is a practical approach to decrease the band gap of the system through an elec tron donor acceptor interaction 48 BTD is one of the most com mon acceptor molecules used in conjugated materials ; u nfortunately, the thiadiazole ring tends to

PAGE 35

35 decompose under basic reaction conditions T hus, i nitial attempts to include the BTD moiety in the ProDOP conjugated molecules using Pd decarboxylative c ross coupling failed since the bases K 2 CO 3 and Cs 2 CO 3 in N methylpyrrolidone (NMP) caused decomposition of 4,7 dibromo BTD S witching to the milder base KHCO 3 however, while keeping the temperature under 90 and increasing dilution, allowed the reaction to proceed in high yield ( 94 % for 22 and 89 % for 23 ). Similar results were observed whether t he anhydrous potassium salt 10 was pre synthesized or formed in situ using potassium carbonate It was also tested to see if t he reaction could be run only with the palladium catalyst without adding a ligand However, t he yield for the tested reaction was lower i. e. 69% yield for compound 1 3 When the reaction was run with PPh 3 instead o f P( o tolyl) 3 a decrease in the reaction yield was also observed i. e. 89% yield for compound 6 As previously mentioned, the reaction did not show any sensitivity towards the presence of water, so the decarboxylative cross coupling was run under similar reaction conditions to some Suzuki Miyaura couplings (Scheme 2 8 ) 49 51 A t oluene/water mixture was employed as solvent with sodium biphenylphosphinobenzene 3 sulfonate, PPh 2 ( m NaSO 3 Ph), as ligand, and 6 and 21 were obtained in high yields (93% and 87% yield, respectively) In this case the carboxylate salt 10 was formed in situ from 9 using potassium carbonate (K 2 CO 3 ) or potassium tert butoxyde ( t BuOK) and tetrabutylammonium bromide ( n Bu 4 NBr) was used as a phase transfer agent These latest reaction conditions provide a good alternat ive for the synthesis of 3,4 dioxypyrrole de rivatives without using NMP, and this result clearly demonstrate d the low sensitivity of the reaction towards the pres ence of water It is noteworthy that water is needed for the

PAGE 36

36 reaction to proceed under these conditions since it is needed to dissolve the potassium salt To rule out a possible product formation via compound 1 the same reaction was run using 1 and no product formation was seen It is noteworthy that tetrahydrofuran (THF) dimethoxyethane (DME ) and diethoxyethane were also tested for the aqueous reaction conditions but only toluene was found to work well Scheme 2 8 Pd mediated decarboxylative cross coupling under aqueous reaction conditions Attempts to ap ply the previously optimized reaction conditions in NMP for the diacid 2 4 failed (Scheme 2 9 ) The initial though t was that the reaction required higher temperature s to proceed, but a gradual increase in the temperature from room temperature to 190 o C did not produce any product formation It was also observed that the formed potassium salt had low solubility and precipitated in the reaction even a t high temperature. Scheme 2 9 Failed attempt to apply the Pd mediated de carboxylative cross coupling to a ProDOP dicarboxylic aci d. Due to these results, the decarboxylation temperatures of various Pro DOP carboxylic acids was studied in greater detail and the results are presented in Scheme 2 10 The synthesis of the se ProDO P acids were carried out by controlled

PAGE 37

37 saponification of the ProDOP diester 2 6 yielding the diacid 2 4 and mono acid 9 To synthesize the mono acid 2 7 compound 9 was decarboxylated first and then subjected to a n additional hydrolysis (as shown in Scheme 2 10 ) then t hermogravimetric analysis (TGA) measurements were performed on the 3,4 propylenedioxypyrroles (ProDOPs) acids 24 2 7 and 9 and also on various potassium carboxylates It is noteworthy that the temperatures presented in Scheme 2 10 correspon d to the minimum required temperature for the protodecarboxylation to occur in the bulk molten compound T his data reveals that the decarboxylation temperature of the dicarboxylic ProDOP diacid 2 4 is lower than the temperature needed to decarboxylate the monoacid containing the ester group ( 9 ), and higher than the temperat ure needed to decarboxylate the monoacid 2 7 Although it is logic not to expect the same reactivity on the respective potassium carboxylates the TGA data pr ovided insight into the react ivity and relative stability of each carboxylate acids and potassium salts, with the latter decomposing around 300 Scheme 2 10 Syntheses and decarboxylation of three different ProDOP acids. Literature reports have shown that the appropriate temperature for the decarboxylative cross coupling not only varies with the tendency of the carboxylic acid to undergo decarboxylation, but also with other factors such as aryl halide, solvent and ligand employed 52,53 and although the decarboxylative cross coupling reaction has

PAGE 38

38 been successfully applied to various monocarboxylic acids, 37, 52,54,55 there are no reports of decarboxylative cross coupling in a dicarboxylic acid Based on the observations made for th e reaction presented in Scheme 2 9 i. e. low solubility of th e potassium salt formed a nd assuming that the low reactivity was re lated to the low solubility of the potassium salt and not to the tendency of the dicarboxylate to undergo decarboxylation the reaction was repeated and two equivalents of tetrabutylammonium bromide were added to incre ase the carboxylate solubility and t he temperature was slowly increased until product formation was observed The r eaction presented o n the upper part of S cheme 2 1 1 show ed that if compound 2 4 is employed in combination with potassium carbonate (>3 equiv.) in the presence of tetrabutylammon ium bromide, the monosubstituted ProDOP derivative 2 8 is synthesized in high yield (92%) and almost exclusively Su rprisingly, the formation of this compound ( 2 8 ) was observed around 55 a low temperature for a decarboxylative cross coupling, but since the reaction proceeded slow ly at this temperature (monitored by TLC) the temperature was then increased to 70 Based on this last result, it was assumed that potassium carbonate was not strong enough to react in situ with both carboxylates present in 2 4 which lead to 28 via a mono decarboxylative cross coupling, followed by a fast proto decarboxylation H ence, the potassium dicarboxylate 2 9 was pre synthesized and subjected to react under similar reaction condi tions ( shown in the lower part of Scheme 2 1 1 ) T he desired compound 2 5 was isolated in acceptable yield demonstrating that the Pd mediated cross coupling reaction can be applied to dicarboxylic acids of the readily decarboxylable 3,4 dioxypyrrole molecule s

PAGE 39

39 Scheme 2 1 1 Pd mediated decarboxylative cross couplings on a ProDOP dicarboxylic acid and a potassium ProDOP dicarboxylate. Other possibilit ies that were explored for the Pd mediated decarboxylative cross coupling of ProDOPs are presented in Scheme 2 1 2 In this case compounds 6 and 14 which were synthesized using the decarboxylative cross coupling and still contained a carboxylic ester, were subjected to a second hydrolysis to generate the potassium carboxylate s 30 and 31 which were then isolated dri ed and reacted with 4 bromopy ridine hydrochloride to produce compound 32 and 33 ; similar conditions to the ones employed for compound 29 were used. Scheme 2 1 2 Pd mediated decarboxylative cross couplings on two potassi um ProDOP dicarboxylate oligomers The derivatization presented in S cheme 2 1 2 cannot be carried out on the benzo[c][1,2,5]thiadiazole (BTD) derivatives, as was explained before, as this type of compound tends to decompose under basic conditions T h us, it is not possible to carry

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40 out the hydrolysis of the ester groups without affecting the BTD unit In this case, it is possible to g enerate a new conjugated molecule by applying the decarboxylative cross coupling on the carboxylic acid 27 (Scheme 2 1 3 ); t his route leads to a new system ( 34 ) that contains two unsubstituted positions on the 3,4 dioxypyrrole molecule that may be employed for further reaction or derivatization The moderate yield of this latest reaction was attributed to possible side reactio ns such as ill defined oligomerization This was assumed since several side products were observed by TLC after 24 hours of reaction, which probably corresponds to oligomerization via direct arylation as was previously shown to occur under these reaction conditions. Scheme 2 1 3 Synthesis of a BTD based oligomer via decarboxylative cross coupling As was mentioned before, the decarboxylative cross coupling of XDOP carboxylic acids can be carried out in a water toluene mi xture, and similar yields as the non aqueous conditions might be achieved Having that in mind, the decarboxylative cross coupling of di esters was also explored and a s shown in S cheme 2 1 4 two possible products can be obtained using this route (mono a nd di subs tituted dioxypyrrole) Various solvent s were tried, and it was found that a mixture of solvent s is required for the reaction to proceed If only toluene /KOH (aq.) was employed the reaction did not produce any product Other solvent s were also tried THF/KOH (aq.) DME/KOH (aq.) D iethoxyethane/KOH (aq.) and no product formation was observed in any of these cases

PAGE 41

41 Scheme 2 14 Decarboxylative cross coupling using a ProDOP diester. Based on various experimental observations, it was concluded that the reaction proceed s at temperatures higher that ~105 C and only when a mixture of toluene/KOH (aq.) and one of the afore mentioned solvents is employed which means that a low polarity solvent such as toluene is needed for the reaction to occur The yield varied from 0 to 79% for the formation of the di substituted product ( 35 ), and unfortunately the reactions were not reproducible and in many cases the product did not form If the concentration of the base [KOH(aq .)] was decreased, compound 36 was also produced Typically, t he reaction require s highly degassed s olvents, and since the in situ hydrolysis of the di ester has to occur, a homogeneous emulsion is needed T o acquire this emulsion a co solvent and a pha se transfer agent ( n Bu 4 NBr or aliquat 336 ) were employed otherwise the reaction does not proceed Due to the numerous failed attempts to reproduce this reaction, this route was finally discarded, and the non aqueous conditions using NMP, or the two step aqueous reaction conditions (hydrolysis then decarboxylative cross coupling using toluene/water) are recommended Experimental Section General Information All reagents and starting materials were purchased from commercial sources and used without further purification, unless otherwise noted All reactions were carried

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42 under argon atmosphere ; unless otherwise mentioned 1 H NMR and 13 C NMR spectra were collected on a Mercury 300 MHz or an Inova 500 MHz High resolution mass spectrometry was performed by t he spectroscopic services in the Chemistry Department of the University of Florida with a Finnigan MAT 95Q Hybrid Sector or a Bruker APEX II FTICR or Agilent 6210 TOF FTIR measurements were performed on a Perkin Elmer Spectrum One FTIR outfitted with a L iTaO 3 detector Thermogravimetric analysis (TGA) measurements were performed with a Perkin Elmer TGA 7 thermogravimetric analyzer Experimental Procedures Ethyl N dodecyl 3,4 (propylene 1,3 dioxy) 5 (4,4,5,5 tetramethyl 1,3,2 dioxaborolan 2 yl)pyrrole 2 ca rboxylate (2) The literature procedure 33 was slightly modified as follows: To a dry 25 mL round bottom flask, containing a stir bar and under argon atmosphere, and equipped with a condenser, was added [Ir(OMe)(C OD)] 2 (5.1 bipyridine (2.4 mg, 0.015 mmol, 3 mol%), and bis(pinacolato)diboron (0.1295 g, 0.510 mmol, 1.1 equiv) Compound 1 was dissolved in 3 mL of degassed heptanes and then transferred via syringe to the flask containin g the other reagents, and the system was equipped with a bubbler The mixture was stirred at 75 C for 24 hours The reaction mixture was cooled down to room temperature and filtered through a short path of a mixture 4:1 of decolorizing carbon: a lumina act ivity 3 The decolorizing carbon: a lumina mixture was flushed with 80 ml of 30% d iethyl ether in hexanes to recover the entire product After removal of the solvent the crude was subjected to high vacuum for 1h at 60 C to remove boron byproducts The pro duct was isolated as a colorless oil, 0.198 g (84.% yield) 1 H NMR (300 MHz, CDCl 3 ): 4.41 (t, 2H, J = 7.4), 4.30 (q, 2H, J = 7.0), 4.11 (m, 4H), 2.17 (m,

PAGE 43

43 2H), 1.59 (m, 2H), 1.40 1.20 (br, 33H), 0.88 (t, 3H, J = 6.4 Hz) 13 C NMR (75 MHz, CDCl 3 ): 161. 1, 146.7, 142.6, 129.9, 113.3, 83.4, 71.7, 71.6, 60.1, 48.0, 33.8, 32.9, 32.1, 29.9 (br), 29.8, 29.6, 29.5, 27.0, 24.9, 22.9, 14.6, 14.3 HRMS (ESI, M+H + ) m/z calcd. for C 28 H 48 BNO 6 H 506.3653, found 506.3696, (ESI, M+Na + ) m/z calcd. for C 28 H 48 BNO 6 Na 528. 3472, found 528.3480. Diethyl 5,5' (1,4 phenylene)bis(N dodecyl 3,4 (propylene 1,3 dioxy)pyrrole 2 carboxylate) ( 6 ) via Suzuki coupling To a 100 mL round bottom flask equipped with a condenser and containing a stir bar and under argon atmosphere was adde d compound 2 (0.183 g, 0.3602 mmol, 2.1 equiv.) K 2 CO 3 (0.320 g), n Bu 4 NBr(28 mg, 0.0865 mmol, 0.5 equiv), and 1,4 dibromobenzene (40.7 mg, 0.1724 mmol, 1 equiv) The system was purged with vacuum argon 4 times and then toluene (4.5 mL, previously degassed) and deionized water (4 mL, previously degassed) were added The mixture was stirred for 30 seconds and Pd( P Ph) 4 (approx. 3 mg) was added The mixture was warmed to 85 90 and stirred vigorously for 18 hours The mixture was cooled to room temperature and partitioned between water and diethyl ether, washed with water (4x), brine (1x), and dried over Na 2 SO 4 ; an oily material was gotten which produced a white solid after treatment with MeOH For quantification purposes, the entire crude was purified by chromatographic column ( s ilica, neutralized with Et 3 N, and e thyl ether: h exanes 1:1), producing 137 mg of a white solid in 95% yield The compound showed the same spectrosc opic characteristics as previously reported. 52 Scheme 2 1 5 Synthesis of ProDOP esters and acids.

PAGE 44

44 The s ynthesis of the ProDOP a cid derivatives 4, 6, 5, and esters 9 and 1 was carried out according to Scheme 2 15. Diethyl N dodecyl 3,4 (propylene 1,3 dioxy)pyrro le 2,5 dicarboxylate ( 26 ) ProDOP diester (5.952 g, 21.0112 mmol, 1 equiv.), n dodecylbromide (6.284 g, 25.2135 mmol, 1.2 equiv.), ground anhydrous K 2 CO 3 (8.7119 g, 63.0336 mmol, 3 equiv.) and DMF (80 mL) were stirred at 95 The reaction was monitored by TLC (silica, 1:2 e thyl ether: h exanes) until disappearance of the starting material (approx. 48 h) T hen the solvent was removed by rotary evaporation, and the resulting crude was partitioned between water and ethyl acetate T he ethyl acetate fraction was washed with water (3x), brine (1x) and dried over anhydrous sodium sulfate The solvent was removed by rotary evaporation and the resulting crude was purified by column chromatography ( s ilica, 1:2 e thyl ether: h exanes); The product was isolated as a c olorless oil 8.538 g (90% yield) 1 H NMR (300 MHz, CDCl 3 ): 4.54 (t, 2H,J = 7.6), 4.32 (q, 4H, J = 7.1 Hz), 4.14 (t, 4H, J = 5.3 Hz), 2.21 (td, 2H, J = 5.3 Hz, J = 10.5 Hz), 1.63 (m, 2H), 1.35 (t, 6H, J = 7.1 Hz), 1.31 1.15 (m, br, 18H), 0.86 ( t, 3H, J = 6.7 Hz). 13 C NMR (75 MHz, CDCl 3 ): 160.9, 142.0, 113.8, 71.8, 60.7, 46.5, 33.5, 32.2, 32.1, 29.9, 29.8, 29.8, 29.8, 29.5, 26.9, 22.9, 14.5, 14.3 FTIR (NaCl Disc) max (cm 1 ): 2925.7 (s), 2854.9(m), 1713.7 (vs), 1531.0 (m ), 1456.0 (m), 1435.5 (m), 1365.1 (m), 1351.3 (m), 1308.8 (m), 1249.5 (s), 1154.7 (s), 1082.3 (m), 1028.9 (m), 776.9 (w). N Dodecyl 3,4 (propylene 1,3 dioxy)pyrrole 2,5 dicarboxylic acid ( 2 4) To a 250 mL round bottom flask containing a stir bar was added compound 26 ( 1.534 g, 3.397 mmol), THF (15 mL) and ethanol (30 mL), After the solid dissolved, 30 mL of KOH [3M] was added, and argon was bubbled through the reaction mixture for 5

PAGE 45

45 minutes. The flask was equipped with a condenser and the reaction mixture was heated to 75 C with strong stirring under argon for 36 hours The organic volatiles were carefully removed in a rotary evaporator, and the aqueous solution was cooled in an ice bath, and the reaction mixture was carefully acidified by slow addition o f HCl 3M. The resulting white precipitate was filtered and washed with deionized water, air dried for about 40 minutes then placed under high vacuum overnight The resulting solid was stirred at ~ 40 C in 25 mL of a mixture 1:25 of e thyl ether: p entanes f or 5 minutes, the mixture was allowed to cool to room temperature, filtered, and washed with cold pentanes The product was isolated as a white solid, 1.303 g (97% yield) 1 H NMR (300 MHz, CDCl 3 ): 10.13 8.8 (br, 2H), 4.82 (t, 2H, J = 7.6 Hz), 4.32 (t 4H, J = 4.8 Hz), 2.38 (quin, 2H, J = 4.4 Hz), 1.68 (m, 2H), 1.29 1.24 (m, 18H), 0.87 (t, 3H, J = 6.3 Hz) 13 C NMR (75 MHz, CDCl 3 ): 159.2, 139.0, 112.8, 73.6, 46.5, 33.5, 32.1, 31.8, 29.9, 29.8, 29.8, 29.8, 29.7, 29.6, 29.5, 26.7, 22.9, 14.3 FTIR ( KBr, pellet) max (cm 1 ): 3223.6 (br, s), 2918.9 (br, s), 2850.5 (br, s), 2630.2 (br, m), 1749.2, 1669.2, 1550.9, 1438.5, 1314.7 (s), 1270.8 (s) 1169.4 (s), 1082.0 (s), 733.2 (s). N Dodecyl 5 (ethoxycarbonyl) 3,4 (propylene 1,3 dioxy )pyrrole 2 carboxylic acid ( 9 ) To a 1000 mL round bottom flask containing a stir bar was added 26 ( 10.050 g, 22.254 mmol, 1 equiv.), THF (95 mL) and ethanol (135 mL), After the solid dissolved, 150 mL of KOH 0.15 M was added, the flask was equipped with a condenser and the reaction mixture was heated to 75 80 C (slightly reflux) with strong stirring under argon After 1 hour 25 mL more of KOH 0.15 M was added, and this was repeated again 30 minutes later (total: 200 mL of KOH 0.15 M) After 30 minutes m ore (2 hours total), the heating was removed The organic volatiles were carefully removed in a rotary

PAGE 46

46 evaporator, and the aqueous solution was chilled by the addition of ~100 mL of crushed ice The reaction mixture was carefully acidified by the additio n of HCl 3M The resulting precipitate was extracted with diethyl ether (3x, 50 mL), washed with deionized water and brine, and dried over anhydrous Na 2 SO 4 The diethyl ether was removed in a rotary evaporator, and t he resulting viscous oil was placed un der high vacuum until it solidified The product was recrystallized from cold pentanes and dried in vacuo to yield 7.206 g (77%) of a white powdery solid Based on TGA data this contains around 97% of monoacid 9 and 3% of the diacid 1 H NMR (300 MHz, CD Cl 3 ): 10.06(br, 1H), 4.67 (t, 2H, J = 7.6 Hz), 4.34 (q, 2H, J = 7.1 Hz), 4.27 (t, 2H, J = 5.0 Hz), 4.15 (t, 2H, J = 4.9 Hz), 2.29 (quin, 2H, J = 4.9 Hz), 1.66 (m, 2H), 1.36 (t, 3H, J = 7.1 Hz), 1.30 1.20 (m, 18H), 0.86 (t, 3H, J = 5.8 Hz) 13 C NMR (75 MHz, CDCl 3 ): 160.47, 159.41, 140.68, 140.06, 115.48, 111.12, 73.56, 71.96, 60.99, 46.45, 33.57, 32.10, 31.96, 29.83, 29.80, 29.76, 29.52, 29.47, 26.76, 22.86, 14.48, 14.29 FTIR (KBr, pellet): (cm 1 ) = 3289.1 (br, w), 2925.3 (s), 2854.6 (m), 1742.7 (m), 1712.6 (s) 1250 (m) MS (DIP CI, CH 4 340 C M+H + ) m/z calcd. for C 23 H 38 N 2 O 6 424.2694, found 424.2696 EA Calculated for C 23 H 37 N 2 O 6 : C (65.22%) H (8.81%) N (3.31%), Found: C (65.47%), H (9.20%), N (3.29%). Ethyl N dodecyl 3,4 (pr opylene 1,3 dioxy)pyrrole 2 carboxylate (1) To a 100 mL round bottom flask was added compound 9 ( 1.2 g, 3.1618 mmol), then the flask was equipped with an vacuum adapter and purged with argon vacuum three times The solid was melted at 130C under vacuum until no bubbling was observed The resulting oil was dissolved in DCM: h exanes 1:1 and filtered through a short path of basic alumina (or silica previously neutralized with triethylamine) The solvent was removed by rotary

PAGE 47

47 evaporation and the resulting colorless oil was subjected to high vacuum for 1 hour. 1 H NMR (300 MHz, CDCl 3 ): 6.39 (s, 1H), 4.27 (q, 2H, J = 7.1 Hz), 4.09 (m, 4H), 3.98 (m, 2H), 2.15 (td, 2H, J = 5.0 Hz, J = 10.2 Hz), 1.64 (m, 2H), 1.32 (t, 3H, J = 7.1 Hz), 1.23 (s, 18H), 0.86 (t, 3H, J = 6.7 Hz) 13 C NMR (75 MHz, CDCl 3 ): 161.2, 143.9, 137.0, 115.2, 107.9, 72 .1, 72.1, 59.7, 50.0, 34.5, 32.1, 31.8, 29.8, 29.8, 29.8, 29.8, 29.5, 29.8, 26.8, 22.9, 14.7, 14.3. N dodecyl 3,4 (propylene 1,3 dioxy)pyrrole 2 carboxylic acid ( 27 ) Compound 1 (3.1618 mmol) was dissolved using 10 mL of THF and 20 mL of EtOH, and transfe rred to a 100 mL round bottom flask equipped with a stir bar and a condenser, then 15 mL of KOH [5M] was added and the mixture was degassed by bubbling argon for 10 minutes The mixture was stirred under argon at 35 40 for 5 days The volatiles were removed by rotary evaporation at room temperature Deionized water (~20 mL) was added to the resulting heterogeneous solution, and then cooled to 5 and acidified by adding HCl [2M] dropwise (alternatively, the potassiu m salt can be isolated by filtration, and then dried under vacuum) The resulting solid was washed with deionized water, and dried under high vacuum The solid was stored under argon in the freezer, 0.780 g (70% yield) The NMR showed that the product i s a mixture 20:1 of compound 27 and ProDOP ester 1 1 H NMR (300 MHz, CDCl 3 ): 9.93 9.02 (br, 1H), 6.49 (s, 1H), 4.23 (t, 2H, J = 4.9 Hz), 4.16 (t, 2H, J = 7.2 Hz), 4.01 (t, 2H, J = 4.9), 2.24 (td, 2H, J = 5.0 Hz, J = 10.0 Hz), 1.69 (m, 2H), 1.36 1.17 (m, 18H), 0.87 (t, 3H, J = 6.6 Hz ) 13 C NMR (75 MHz, CDCl 3 ): 159.6 141.9, 135.6, 116.0, 106.6, 73.8, 72.2, 49.5, 34.4, 32.1, 31.5, 29.8, 29.8, 29.8, 29.7, 29.6, 29.5, 26.7, 22.9, 14.3 FTIR (NaCl Disc) max (cm 1 ): 3324.8 (br, w), 3105.4 (br, w), 2924.7, 2924.7 (vs),

PAGE 48

48 2854.4 (s) 2645.5 (br, w), 17 32.4 (s), 1652.3 (s), 1525.1 (m), 1456.2 (s), 1407.9 (s), 1365.2 9 (s), 1294.6 (m), 1062.9 (s), 795.7 (w). Potassium N dodecyl 5 (ethoxycarbonyl) 3,4 (propylene 1,3 dioxy)pyrrole 2 carboxylate ( 10 ) Two possible methods can be employed to make this compou nd. ( A) To a dry 250 mL round bottom flask containing a stir bar and argon was added compound 9 (3.0030 g, 7.0902 mmol, 1 equiv.) The flask was equipped with a septum and 30 mL of anhydrous THF was added via cannula After dissolution of compound 9 a s olution of potassium t butoxide (0.7596 g, 7.0902 mmol, 1 equiv) in THF (100 mL) was added via cannula The viscous solution was stirred for 30 minutes and then the solvent was carefully removed in a rotary evaporator, assuring anhydrous conditions 3.27 0 g of sticky white solid was gotten, 100 % yield 1 H NMR (300 MHz, CDCl 3 ): H 4.40 (t, 2H, J = 7.3 Hz), 4.12 (q, 2H, J = 7.1 Hz), 3.94 (t, 2H, J = 4.9 Hz), 3.83 (t, 2H, J= 4.8 Hz), 2.00 (quin, 1H, J = 4.9 Hz), 1.47 (m, 2H), 1.21 (m, 18H), 0.85 (t, 3H, J = 6.5 Hz) FTIR (KBr, pellet): (cm 1 ) = 2925.8 (s), 2855.3 (m), 1701.0 (s), 1602.7 (s), 1365.8 (s), 1344.4 (s), 1249.6 (m) ( B) Alternatively this compound can be made in wate r using KOH but the product has to be dried under vacuu m at 50 C for three hours. Scheme 2 16. General p rocedure 1 : d ecarboxylative cross coupling using the potassium carboxylate 10 Diethyl 5,5' (1,4 phenylene)bis(N dodecyl 3,4 (propylene 1,3 dioxy)pyrrole 2 carboxylate) ( 6 ) In a typical procedure, to a dry 25 mL round bottom flask containing a

PAGE 49

49 stir bar and argon atmosphere was added compound 10 (0.554 g, 1.200 mmol, 2.2 equiv.), 1,4 dibromobenzene (0.129 g, 0.545 mmol, 1 equiv), tri(o tolyl)phosphine (6.6 mg, 0.022 mmol, 4 m ol % ) and palladium(II) acetylacetonate (3.3 mg, 0.011 mmol, 2 mol % ) The flask was equipped with an air cooled condenser then an inlet vacuum adapter is connected to the top of the condenser and the system was purged with vacuum argon four times N methy lpyrrolidone (1.5 mL, previously degassed) was added via syringe The inlet vacuum adapter is changed to a septum and a bubbler (containing silicone oil) was connected to it The bubbler was flushed with argon for 2 minutes by connecting an argon source through the septum The reaction mixture was warmed to 95 C and stirred for 48 hours The solution was t hen cooled down to room temperature, diluted with 40 mL of a mixture 3:2 d iethyl ether: h exanes, and filtered through a short path of alumina (neutral, activity 3) The alumina was flushed with a mixture 3:2 d iethyl ether: h exanes to recover the entire product The mixture was washed with 30 mL deionized water (four times) and brine, dried over Na 2 SO 4 and the organic solvent mixture (including the resid ual NMP) was removed in a rotary evaporator The resulting crude solid was recrystallized from methanol yielding 0.436 g of a white solid, 96% yield 1 H NMR (300 MHz, CDCl 3 ): 7.42 (s, 4H), 4.34 (q, 4H, J = 7.1 Hz ), 4.19 (m, 8H), 4.01 (t, 4H, J = 4.0 Hz), 2.20 (m, 4H), 1.47 (m, 4H), 1.37 (t, 6H, J = 7.1 Hz), 1.32 1.12 (m, 36H), 0.86 (t, 6H, J = 6.6 Hz) 13 C NMR (75 MHz, CDCl 3 ): 161.4, 144.6, 135.6, 130.3, 129.4, 127.1, 10 8.3, 72.1, 72.0, 59.9, 46.2, 34.2, 32.1, 31.8, 29.9 (br), 29.82 (br), 29.7 (br), 29.5, 29.3, 26.7, 22.9, 14.8, 14.3 HRMS (ESI TOF, M+H + ) m/z calcd. for C 50 H 77 N 2 O 8 833.5674, found 833.5693 EA calculated for

PAGE 50

50 C 50 H 76 N 2 O 8 : C (72.08%) H (9.19%) N (3.36%) F ound: C (72.02%), H (9.59%), N (3.31%). Scheme 2 17 General procedure 2: d ecarboxylative cross coupling of compound 9 using potassium carbonate as base. Diethyl 5,5' (1,4 phenylene) bis(N dodecyl 3,4 (propylene 1,3 dioxy) pyrrole 2 carboxylate) ( 6 ) To a 25 mL round bottom flask, containing argon atmosphere and equipped with an air cooled condenser and a stir bar, was added compound 9 (0.211g, 0.457 mmol, 2.2 equiv.), 1,4 dibromobenzene (0.049g, 0.208 mmol, 1 equiv) and fi nely ground anhydrous potassium carbonate (0.063 g, 0.457 mmol, 2.2 equiv.) An inlet vacuum adapter was connected to the condenser and the system was purged with vacuum argon four times, and then 1.5 mL of degassed N methylpyrrolidone was added via syrin ge The reaction mixture was warmed to 60 C and stirred for 45 min Tri(o tolyl)phosphine (2.5 mg, 0.009 mmol, 4 mol % ) and palladium(II) acetylacetonate (1.3 mg, 0.004 mmol, 2 mol % ) were added to the flask The inlet vacuum adapter is changed to a septu m, a bubbler (containing silicone oil) was connected to the septum and the bubbler was flushed with argon for 2 minutes by connecting an argon source to the septum The reaction mixture was warmed to 100 C and stirred for 48 hours, then it was cooled down to room temperature, diluted with a mixture 3:2 d iethyl ether: h exanes, filtered through a short path of alumina (neutral, activity 3), and the alumina was flushed with 3:2 d iethyl ether: h exanes mixture to recover the entire product The resulting mixture (solvent and crude) was washed with water (4 times), brine, and dried over

PAGE 51

51 anhydrous Na 2 SO 4 The solvent is removed in a rotary evaporator and the resulting crude was purified by chromatographic column on silica (previously neutralized with Et 3 N) using 1 :3 Et 2 O: h exanes as eluent, yielding a white solid, 0.170 g, 98% yield. 1 H NMR (300 MHz, CDCl 3 ): 7.39 (s, 4H), 4.32 (q, 4H, J = 7.1 Hz ), 4.17 (m, 8H), 3.99 (t, 4H, J = 4.0 Hz), 2.18 (m, 4H), 1.47 (m, 4H), 1.35 (t, 6H, J = 7.1 Hz), 1.30 1.10 (m, 36H), 0 .84 (t, 6H, J = 6.6 Hz) 13 C NMR (75 MHz, CDCl 3 ): 161.43, 144.57, 135.61, 130.33, 129.44, 127.14, 108.26, 72.07, 71.98, 59.92, 46.17, 34.23, 32.11, 31.81, 29.87 (br), 29.82 (br), 29.71 (br), 29.54, 29.31, 26.68, 22.88, 14.76, 14.31 HRMS (ESI TOF, M+H + ) m/z calcd. for C 50 H 76 N 2 O 8 H 833.5674, found 833.5709. Scheme 2 18. General procedure 3: decarboxylative cross coupling using compound 9 in toluene/water. Ethyl N dodecyl 5 (thiophen 2 yl) 3,4 (propylene 1,3 dioxy)pyrrole 2 carboxylate ( 21 ) To a dry 50 mL round bottom flask containing a stir bar and argon atmosphere was added compound 9 (0.131 g, 0.309 mmol, 1 equiv.), Pd(acac) 2 (1.0 mg, 0.003 mmol, 2 mol % ), ( m NaSO 3 Ph)Ph 2 P (2.2 mg, 0.006 mmol, 4 mol % ), n Bu 4 NBr (0.050 g, 0.155 mmol, 0.5 equiv.), K 2 CO 3 ( 0.8 g ) and aliquat 336 (a drop) The flask was equipped with a water cooled condenser An inlet vacuum adapter was connected to the condenser and the system was purged with vacuum argon four times Four mL of toluene (pr eviously degassed), 0.04 mL of 2 bromothiophene (0.066 g, 0.402 mmol, 1.3 equiv.) and 2 mL of deionized water (previously degassed) were added The reaction mixture was warmed up to 110 C and strongly stirred for 36h hours The

PAGE 52

52 reaction mixture was part itioned between diethyl ether and water, and the organic layer was washed with water (2 times), brine and dried over Na 2 SO 4 The organic solvent was removed in a rotary evaporator and the crude was purified by chromatographic column on silica (previously neutralized with Et 3 N) using 1:4 Et 2 O: h exanes as eluent, yielding a pale yellow dense oil, 0.124 g, 87% yield 1 H NMR (300 MHz, CDCl 3 ): 7.41 (dd, 1H, J=3.8 Hz, J = 3.9 Hz), 7.10 (m, 2H), 4.33 (q, 2H, J = 7.1 Hz), 4.23 (t, 2H, J = 7.7 Hz), 4.17 (t, 2H, J = 5.1 Hz), 4.02 (t, 2H, J = 5.2), 2.20 (quin, 2H, J = 5.0 Hz), 1.61 (m, 2H), 1.36 (t, 3H, J = 7.1 Hz), 1.32 1.13 (m, 18H), 0.87 (t, 3H, J = 6.7 Hz) 13 C NMR (75 MHz, CDCl 3 ): 161.3, 143.8, 136.2, 130.2, 128.7, 127.3, 127.1, 119.9, 108.6, 72.1, 72.0, 60.0, 46.2, 34.2, 32.1, 31.9, 29.8, 29.8, 29.7, 29.7, 29.5, 29.4, 26.7, 22.9, 14.7, 14.3 HRMS (APCI, M+H + ) m/z calcd. for C 26 H 40 NO 4 S 462.2 673, found 462.2709 EA calculated for C 26 H 39 NO 4 S: C (67.64%) H (8.51%) N (3.03%) Found: C (67.77%), H (8.64%), N (2.92%). Diethyl 5,5' (9 methylcarbazole 3,6 diyl)bis(N dodecyl 3,4 (propylene 1,3 dioxy)pyrrole 2 carboxylate) ( 12 ) The reaction was perf ormed according to general procedure 1 at 110 and using potassium carboxylate 10 (0.554 g, 1.2 mmol, 2.2 equiv.) 3,6 dibromo 9 methylcarbazole (0.185 g, 0.545 mmol, 1 equiv), tri( o tolyl)phosphine (6.6 mg, 0.022 mmol, 4 mol % ), palladium(II) acetylacetonate (3.3 mg, 0.011 mmol, 2 mol % ) and anhydrou s N methylpyrrolidone (1.5 mL, previously degassed) The crude was purified by chromatographic column on silica (previously neutralized with Et 3 N) using 1:1 Et 2 O: h exanes as eluent A pale yellow sticky solid was gotten, 0.470g, 92% yield 1 H NMR (300 MH z, CDCl 3 ): 8.07 (t, 2H, J = 1.0 Hz), 7.48 (d, 4H, J = 1.0 Hz), 4.35 (q, 4H, J = 7.1 Hz), 4.21 (m, 8H), 3.99 (t, 4H, J = 5.1), 3.92

PAGE 53

53 (s, 3H), 2.20 (quin, 4H, J = 4.9 Hz), 1.49 (m, 4H), 1.39 (t, 6H, J = 7.1 Hz), 1.27 0.98 (m, 36H), 0.86 (t, 6H, J = 6.9 Hz) 13 C NMR (75 MHz, CDCl 3 ): 161.5, 144.6, 141.2, 135.4, 128.6, 128.6, 123.0, 122.9, 120.8, 108.7, 107.3, 72.1, 72.0, 59.8, 46.1, 34.3, 32.1, 31.8, 29.8, 29.8, 29.7, 29.7, 29.5, 29.5, 29.3, 26.7, 22.9, 14.8, 14.3 HRMS (APPI, M+H + ) m/z calcd. for C 57 H 82 N 3 O 8 936.6096, found 936.6103. Diethyl 5,5' (2,3 dihydrothieno[3,4 b][1,4]dioxine 5,7 diyl)bis(N dodecyl 3,4 (propylene 1,3 dioxy)pyrrole 2 carboxylate) ( 14 ) The reaction was performed according to general procedure 1 at 90 and using potassium carboxylat e 10 (0.554 g, 1.2 mmo l, 2.2 equiv.), 1,5 dibromoEDOT (0.164 g, 0.545 mmol, 1 equiv), tri( o tolyl)phosphine (6.6 mg, 0.022 mmol, 4 mol % ), palladium(II) acetylacetonate (3.3 mg, 0.011 mmol, 2 mol % ) and anhydrous N methylpyrrolidone (1.5 mL, previously degas sed) The crude was purified by chromatographic column on silica (previously neutralized with Et 3 N) using 1:3 Et 2 O: h exanes as eluent, yielding a pale yellow sticky oil which solidified after several days under high vacuum, 0.485g, 99% yield 1 H NMR (300 MHz, CDCl 3 ): 4.31 (q, 4H, J = 7.1 Hz), 4.24 (s, 4H), 4.17 (m, 8H), 4.02 (t, 4H, J = 5.08 Hz), 2.18 (quin, 4H, J = 5.0 Hz), 1.58 (m, 4H), 1.35 (t, 6H, J = 7.1 Hz), 1.28 1.10 (m, 36H), 0.86 (t, 6H, J = 6.7 Hz) 13 C NMR (75 MHz, CDCl 3 ): 161.1, 143.8, 1 39.5, 136.8, 116.2, 109.3, 106.0, 72.0, 64.7, 59.9, 46.6, 34.3, 32.1, 31.9, 29.8, 29.9, 29.8, 29.5, 27.0, 22.9, 14.7, 14.3 HRMS (APPI, M+H + ) m/z calcd. for C 50 H 77 N 2 O 10 S 897.5293, found 897.5311. Diethyl 5,5' (9,9 dioctylfluorene 2,7 diyl) bis(N dodecyl 3 ,4 (propylene 1,3 dioxy)pyrrole 2 carboxylate) ( 13 ) The reaction was performed according to general procedure 1 at 105 and using potassium carboxylate 10 (0.554 g, 1.2 mmol, 2.2

PAGE 54

54 equiv.), 9,9 dioctyl 2,7 dibromofluorene (0.299 g, 0.545 mmol, 1 equiv), tri( o tolyl)phosphine (6.6 mg, 0.022 mmol, 4 mol % ), palladium(II) acetylacetonate (3.3 mg, 0.011 mmol, 2 mol % ) and anhydr ous N methylpyrrolidone (1.5 mL, previously degassed) The crude was purified by chromatographic column on silica (previously neutralized with Et 3 N) using 1:3 Et 2 O: h exanes as eluent A colorless sticky oil was gotten, 0.606g, 97% yield 1 H NMR (300 MHz, CDCl 3 ): 7.76 (d, 2H, J = 8.4 Hz), 7.35 (m, 4H), 4.34 (q, 4H, J = 7.1 Hz), 4.21 (m, 8H), 4.01 (t, 4H, J = 5.1 Hz), 2.21 (quin, 4H, J = 5.0 Hz), 1.98 (m, 4H), 1.47 (m, 4H), 1.38 (t, 6H, J = 7.1 Hz), 1.27 097 (m, 56H), 0.85 (t, 6H, J = 6.8 Hz), 0.80 (t, 6H, J = 6.9 Hz), 0.72 (m, 4H) 13 C NMR (75 MHz, CDCl 3 ): 161.5, 151.2, 144.8, 140.6, 135.5, 129.4, 128.6, 128.4, 125.0, 120.0, 108.0, 72.0, 72.0, 59.9, 55.4, 46.3, 46.2, 46.2, 40.5, 34.3, 32.1, 32.0, 31.8, 30.3, 29.8, 29.9, 29.8, 29.8, 29.7, 29.5, 29.5, 26.8, 24.3, 22.9, 22.8, 14.8, 14.3, 14.3 HRMS (APPI, M+H + ) m/z calcd. for C 74 H 115 N 2 O 8 1145.8491, found 1145.8505. Diethyl 5,5' (naphthalene 2,6 diyl) bis(N dodecyl 3,4 (propylene 1,3 dioxy)pyrrole 2 carboxylate) ( 16 ) The reaction was performed according to genera l procedure 1 at 105 and using potassium carboxylate 10 (0.554 g, 1.2 mmol, 2.2 equiv.), 2,6 dibromonaphthalene (0.156 g, 0.545 mmol, 1 equiv), tri( o tolyl)phosphine (6.6 mg, 0.022 mmol, 4 mol % ) and palladium(II) acetylacetonate (3.3 mg, 0.011 mmol, 2 mol % ) and anhydrous N methylpyrrolidone (1.5 mL, previously degassed) The crude was recrystallized from MeOH yielding a yellow solid, 0.458g, 95% yield 1 H NMR (300 MHz, CDCl 3 ): 7.92 (d, 2H, J = 8.4 Hz), 7.86 (s, 2H), 7.51 (d, 2H, J = 8.4 Hz), 4.36 (q, 4H, J = 7.1 Hz), 4.22 (m, 8H), 3.98 (t, 4H, J = 5.0 Hz), 2.20 (m, 4H), 1.51 (m, 4H), 1.39 (t, 6H, J = 7.1 Hz), 1.34 0.93 (m, 36H), 0.86 (t, 6H, J = 6.7 Hz) 13 C NMR (75

PAGE 55

55 MHz, CDCl 3 ): 161.4, 144.6, 135.8, 132.7, 129.6, 128.5, 128.4, 128.0, 127.5, 108.3, 72.1, 72.0, 5 9.9, 46.3, 34.3, 32.1, 31.9, 29.8, 29.8, 29.6, 29.5, 29.3, 26.7, 22.9, 14.8, 14.3 HRMS (ESI, M+Na + ) m/z calcd. for C 54 H 78 N 2 O 8 Na 905.5650, found 905.5719. Diethyl 5,5' (5,5' (2,5 bis(dodecyloxy) 1,4 phenylene)bis(thiophene 5,2 diyl)) bis(N dodecyl 3,4 (pr opylene 1,3 dioxy)pyrrole 2 carboxylate) ( 20 ) The reaction was performed according to general procedure 1 at 105 and using potassium carboxylate 10 (0.252 g, 0.546 mmol, 2.2 equiv.), 5,5' (2,5 bis(dodecyloxy) 1,4 phenylene)bis(2 bromothiophene) (0.191 g, 0.248 mmol, 1 equiv), tri( o tolyl)phosphine (3.0 mg, 0.010 mmol, 4 mol % ), palladium(II) acetylacetonate (1.5 mg, 0.005 mmol, 2 mol % ) and anhydrous N methylpyrrolidone (3 mL, previously degassed), differing only in that the workup was modified as follow s : after the reaction was cooled down to room temperature 50 mL of deionized water was added and the resulting solid was filtered and washed with a 1:1 mixture of w ater:MeOH The solid was dissolved with ethyl acetate and filtered through a very short path of alumina (neutral, activity 3) The alumina was flushed with a mixture 2:3 e thyl acetate: h exanes to recover the entire product The solvent was removed in vacuo and the resulting crude solid was stirred in hot EtOH, the mixture was cooled down and filt ered yielding a yellow orange solid, 0.325g, 96% yield 1 H NMR (300 MHz, C 6 D 6 ): 7.63 (d, 2H, J = 3.9 Hz), 7.35 (s, 2H), 7.30 (d, 2H, J = 3.9 Hz), 4.65 (t, 4H, J = 7.4 Hz), 4.32 (q, 4H, J = 7.1 Hz), 3.85 (m, 8H), 3.74 (t, 4H, J = 5.0 Hz), 1.85 (m, 8H), 1.65 (m, 4H), 1.20 120 (m, 78H), 0.92 (m, 12H) 13 C NMR (75 MHz, C 6 D 6 ): 161.9, 1 50.3, 144.9, 141.4, 137.4, 131.6, 128.9, 126.1, 123.8, 121.0, 113.0, 109.9, 72.3, 72.1, 70.0, 60.0, 46.7, 34.8, 32.7, 32.7, 30.6, 30.5, 30.5, 30.5, 30.4, 30.3, 30.2, 30.2, 30.0, 27.4, 27.1, 23.5, 15.1, 14.8 EA calculated for

PAGE 56

56 C 82 H 128 N 2 O 10 S 2 : C (72.10%) H (9 .44%) N (2.05%), Found: C (71.88%), H (9.27%), N (1.99%). Diethyl 5,5' (thiophene 2,5 diyl) bis(N dodecyl 3,4 (propylene 1,3 dioxy)pyrrole 2 carboxylate) ( 11 ) To a dry 25 mL round bottom flask containing a stir bar and argon atmosphere was added compou nd 10 (0.561 g, 1.215 mmol, 2.2 equiv.), tri( o tolyl)phosphine (6.5 mg, 0.021 mmol, 4 mol % ) and palladium(II) acetylacetonate (3.2 mg, 0.011 mmol, 2 mol % ) The flask was equipped with an air cooled condenser, then, the system is purged with vacuum argon f our times Anhydrous N methylpyrrolidone (1.5 mL, previously degassed) and 2,5 dibromothiophene (0.06 mL, 0.129 g, 0.532 m mol, 1 equiv.) were added via syringe The vacuum adapter is changed to a septum and a bubb ler was connected to it The reaction mi xture was warmed to 95 C and stirred for 36 hours, t hen it was cooled down to room temperature, diluted with 40 mL of a mixture 3:2 d iethyl ether: h exanes, and filtered through a short path of alumina (neutral, activity 3) The alumina was washed with the mixture 3:2 d iethyl ether: h exanes to recover the entire product The mixture was washed with 30 mL deionized water (four times), brine and dried over Na 2 SO 4 The solvent mixture (including the residual NMP) was removed in a rotary evaporator The result ing solid was recrystallized from ethanol yielding 0.424 g of a pale yellow solid, 95% yield 1 H NMR (300 MHz, CDCl 3 ): 7.02 (s, 2H), 4.21 (m, 8H), 4.07 (t, 4H, J = 5.0 Hz), 3.94 (t, 4H, J = 5.0 Hz), 2.10 (quin, 4H, J = 5.0 Hz), 1.44 (m, 4H), 1.26 (t, 6H J = 7.0 Hz), 1.18 1.02 (br, 36H), 0.76 (t, 6H, J = 6.6 Hz) 13 C NMR (75 MHz, CDCl 3 ): 161.02, 143.65, 136.00, 131.13, 128.01, 119.41, 108.68, 71.81, 59.78, 46.12, 33.94, 31.89, 31.77,

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57 29.65, 29.61, 29.57, 29.32, 29.24, 26.59, 22.65, 14.50, 14.08 HRMS (APPI, M+H + ) m/z calcd. for C 48 H 75 N 2 O 8 S 839.5259, found 839.5239. Scheme 2 19. Dec arboxylative cross coupling of ProDOP monoacid 9 with BTD based molecules using potassium bicarbonate. Diethyl 5,5' (benzo[c][1,2,5]thiadiaz ole 4,7 diyl)bis(thiophene 5,2 diyl)bis(N dodecyl 3,4 (propylene 1,3 dioxy)pyrrole 2 carboxylate) ( 23 ) To a dry 25 mL round bottom flask containing a stir bar and under argon atmosphere was added compound 9 (0.060 g, 0.1417 mmol, 2.2 equiv.), and finely ground anhydrous potassium bicarbonate (0.0142 g, 0.1417 mmol, 2.2 equiv.) The flask was equipped with an air cooled condenser; an inlet vacuum adapter was connected to the top of the condenser, and the system was purged with vacuum argon four times, the n NMP (5.5 mL, previously degassed) was added via syringe The mixture was warmed to 50 C and stirred for 1 hour (vacuum was slightly applied several times to remove CO 2 and to help the neutralization process), then 4,7 bis(5 bromothiophen 2 yl)benzo[c][1 ,2,5]thiadiazole (29.5 mg, 0.0644 mmol, 1 equiv), tri( o tolyl)phosphine (1.2 mg, 0.0039 mmol, 6 mol % ) and palladium(II) acetylacetonate (0.6 mg, 0.0019 mmol, 3 mol % ) were added The system was then equipped with a septum and a bubbler (containing silicon oil); the reaction mixture was warmed 90 C and stirred for 24 hours The solvent was removed in a rotary evaporator at 80 C then the crude was dissolved in h exanes:ethyl acetate 3:1 and filtered through a short path (~1 cm) of neutral alumina (activity 3); the alumina

PAGE 58

58 was flushed with the h exanes: EtO Ac mixture to recover the entire product The solvent was removed in a rotary evaporator, and the resulting crude oil was dissolved in hexanes washed with deionized water (3x), brine (1x), and dried over Na 2 SO 4 The mixture was filtered and the solvent was removed in a rotary evaporator; the resulting sticky solid was subjected to vacuum overnight T hen 2 mL of ethanol was added, and the mixture was slightly warmed, and diethyl ether was added until the s olid dissolved Slow evaporation of the diethyl ether produced a purple powdery solid, which was filtered, washed with ethanol, and air dried for 2 minutes, then put under vacuum to remove the solvent traces, 60.8 mg (89% yield) 1 H NMR (300 MHz, CDCl 3 ): H 8.17 (d, 2H, J = 3.9 Hz), 7.89 (s, 2H), 7.24 (d, 2H, J = 3.9 Hz), 4.35 (q, 8H, J = 7.1 Hz), 4.20 (t, 4H, J = 4.9 Hz), 4.09 (t, 4H, J = 5.1 Hz), 2.24 (m, 4H), 1.68 (m, 4H), 1.38 (t, 6H, J = 7.1 Hz), 1.19 (m, 34H), 0.84 (t, 6H, J = 6.8 Hz) 13 C NMR (75 MHz, CDCl 3 ): 161.3, 152.8, 144.0, 140.5, 136.5, 131.8, 129.3, 127.9, 125.9, 125.7, 119.9, 109.3, 72.2, 72.1, 60.1, 46.5, 34.2, 32.1, 32.0, 29.9, 29.8, 29.8, 29.8, 29.6, 29.4, 26.8, 22.9, 14.8, 14.3 HRMS (DART TOF, M+H + ) m/z calcd. for C 58 H 7 8 N 4 O 8 S 3 H 1055.5055, found 1055.5089. Diethyl 5,5' (benzo[c][1,2,5]thiadiazole 4,7 diyl)bis(N dodecyl 3,4 (propylene 1,3 dioxy)pyrrole 2 carboxylate) ( 22 ) Using compound 9 (0.1700 g, 0.4014 mmol, 2.1 equiv.), finely ground anhydrous potassium bicarbonate (0.0398 g, 0.3976 mmol, 2.08 equiv.), NMP (9 mL, previously degassed), 4,7 dibromobenzo[c][1,2,5]thiadiazole (56.2 mg, 0.1911 mmol, 1 equiv), tri( o tolyl)phosphine (4.6 mg, 0.0153 mmol, 8 mol % ) and palladium(II) acetylacetonate (2.3 mg, 0.0077 mmol, 4 mol % ), the reaction was run for 72 hours using the same procedure as for 23 although the workup was modified as

PAGE 59

59 follows: The solvent was concentrated by rotary evaporation at 80 C to ~1 mL ; then the mixture was dissolved in diethyl ether; washed with water (5 x), brine (1x), and dried over Na 2 SO 4 and purified by chromatographic column on silica using 1:1 d iethyl ether: h exanes as eluent The product was isolated as an orange solid (paraffin like), 0.160 g (94% yield) 1 H NMR (300 MHz, CDCl 3 ): 7.63 (s, 2H), 4.34 (dd, 4H, J = 7.0 Hz, J = 14.1 Hz), 4.22 (br, 8H), 3.99 (m, 4H), 2.18 (m, 4H), 1.50 1.28 (m, 10H), 1.28 0.88 (m, 36H, ), 0.84 (t, 6H, J = 7.1Hz ) 13 C NMR (75 MHz, CDCl 3 ): 161.3, 154.2, 144.3, 136.8, 131.5, 123.5, 122.6, 109.5, 72.0, 72.0, 60.0, 46.9, 34.3, 32.0, 31.8, 29.8, 29.7, 29.6, 29.6, 29.5, 29.2, 26.6, 22.8, 14.7, 14.2 HRMS (DART, M+H + ) m/z calcd. for C 50 H 74 N 4 O 8 SH 891.5300, found 891.5295. Scheme 2 20 Decarboxylative cross coupling o f ProDOP diacid 24 using potassium carbonate and tetra( n butyl)ammonium bromide. N D odecyl 3,4 (propylene 1,3 dioxy) 2 (thiophen 2 yl)pyrrole ( 2 8 ) To a dry 25 mL round bottom flask containing a stir bar and under argon atmosphere was added diacid 2 4 (0.1 37 g, 0.3462 mmol, 1 equiv.), finely ground anhydrous potassium carbonate (0.144 g, 1.0386 mmol, 3 equiv.) and n Bu 4 NBr (0.112 g, 0.3462 mmol, 1 equiv.) The flask was equipped with an air cooled condenser; a vacuum adapter was connected to the top of the condenser and the system was purged with vacuum argon four times, and then N methylpyrrolidone (4 mL, previously degassed) was added via syringe The mixture was warmed to 70C and stirred for 1 hour, and then 0.074 mL of 2 bromothiophene (0.124g, 0.7615 mmol, 2.2 equiv), tri( o tolyl)phosphine (4.7 mg,

PAGE 60

60 0.0152 mmol, 2 mol % ) and palladium(II) acetylacetonate (2.3 mg, 0.0076 mmol, 1 mol % ) were added The system was then equipped with a septum and a bubbler (containing silicon oil); the reaction mixture was stirred at 70 75 for 48 hours The mixture was cooled to room temperature and partitioned between diethyl ether and water in a separatory funnel, then washed with plenty of water (5x), brine (1x), and dried over Na 2 SO 4 ; the solvent was removed in a rotary evaporator an d the resulting crude was purified by chromatographic column on silica (previously neutralized with triethylamine ) using 1:2 d iethyl ether: h exanes as eluent The product was isolated as a pale yellow oil, which was subjected to high vacuum for 6 hours and then stored under argon atmosphere, 0.124 g (92% yield). 1 H NMR (300 MHz, CD 2 Cl 2 ): 7.34 (ddd, 1H, J = 1.3 Hz, J = 5.0 Hz, J = 15.9 Hz), 7.09 (m, 1H), 7.01 (dd, 1H, J = 1.2 Hz, J = 3.5 Hz), 6.29 (s, 1H), 3.98 (m, 4H), 3.79 (t, 2H, J = 7.4 Hz), 2.13 (m, 2H), 1.61 (td, 2H, J = 5.2 Hz, J = 10.4 Hz), 1.48 1.00 (m, br, 18H), 0.88 (t, 3H, J = 6.7 Hz) 13 C NMR (75 MHz, D 2 CCl 2 ): C 138.9, 127.5, 127.4, 127.3, 126.5, 125.9, 125.3, 107.6, 73.1, 72.9, 48.2, 35.8, 32.5, 31.7, 30.2, 30.1, 30.0, 29.9, 29.7, 29.5, 27.1, 23.3, 14.5 HRMS (ESI DART, M+H + ) m/z calcd. for C 23 H 35 NO 2 SH 390.2461, found 390.2459. Scheme 2 21 Decarboxylative cross coupling using the ProDOP dicarboxylate salt 29 Potassium N dodecyl 3,4 (propylene 1,3 dio xy)pyrrole 2,5 dicarboxylate (29 ) This compound can be prepared by two diff erent methods: To a dry 50 mL round bottom flask containing a stir bar and under argon atmosphere was added 0.2270 g of t BuOK (2.0228 mmol, 2 equiv.) The flask was equipped with a septum and then 4 mL

PAGE 61

61 of anhydrous t BuOH and 15 mL of anhydrous THF were added via cannula After the t BuOK dissolved; a solution of compound 24 (0.4000g, 1.0114 mmol, 1 equiv.) in 10 ml of anhydrous THF was slowly added via cannula The mixture was stirred for 30 minutes, and then the solvent was carefully removed in a rota ry evaporator (anhydrous conditions were assured by flushing the rotary evaporator with nitrogen) A pale tan solid was gotten, which was subjected to high vacuum overnight, 0.4771 g (100% yield) FTIR (KBr, pellet) (cm 1 ): 3391.1 (br, w), 2925.8 (s), 2 853.7 (s), 1618.5 (s), 1589.9 (s), 1419.5 (S), 1340.5 (s), 1132.9 (m), 1081.3 (s), 806.1 (m) Alternatively, the procedure was also carried out using deionized water (4 mL), potassium hydroxide (0.1135 g, 2.0228 mmol, 2 equiv.) and compound 24 (0.4000g, 1 .0114 mmol, 1 equiv.), After removal of the water by rotary evaporation the resulting solid was dried under vacuum at 60C for 3h. N Dodecyl 2,5 di(thiophen 2 yl) 3,4 (propylene 1,3 dioxy)pyrrole ( 25 ) To a dry 25 mL round bottom flask containing a stir b ar and under argon atmosphere was added compound 29 (0.112 g, 0.2375 mmol, 1 equiv.), n Bu 4 NBr (0.153 g, 0.4749 mmol, 2 equiv.), tri( o tolyl)phosp hine (6.4 mg, 0.021 mmol, 4 mol %), and palladium(II) acetylacetonate (3.2 mg, 0.011 mmol, 2 mol % ) The flask was equipped with an air cooled condenser, then an inlet vacuum adapter was connected to the top of the condenser and the system was purged with vacuum argon four times, and then 0.05 mL of 2 bromothiophene (0.0852 g, 0.5224 mmol, 2.2 equiv), and anhydrous N methylpyrrolidone (2 mL, previously degassed) were added via syringe The system was then equipped with silicone oil bubbler, and the reaction mixture was warmed to 70 75C and stirred for 36 hours On cooling to room temperature, the mixture was

PAGE 62

62 part itioned between diethyl ether and water; washed with water (5x), brine (1x), and dried over Na 2 SO 4 The organic solvent mixture (including the residual NMP) was removed in a rotary evaporator The resulting crude was purified by chromatographic column on silica (previously neutralized with Et 3 N) using 1:4 Et 2 O: h exanes as eluent The product was isolated as a pale yellow paraffin like solid, 0.078g, 69% yield 1 H NMR (300 MHz, CDCl 3 ): H 7.35 (dd, 2H, J = 2.4 Hz, J = 3.8 Hz), 7.10 (m, 4H), 4.05 (t, 4H, J = 5.0 Hz), 4.00 (t, 2H, J = 7.9 Hz), 2.07 (quin, 2H, J = 5.0 Hz), 1.47 (m, 2H), 1.34 1.09 (br, m, 18H), 0.90 (t, 3H, J = 6.8 Hz ) 13 C NMR (75 MHz, CDCl 3 ): C 137.3, 132.0, 127.2, 126.9, 125.5, 113.1, 72.5, 45.4, 35.0, 32.1, 31.1, 29.8, 29.7, 29.5, 29 .1, 26.5, 22.9, 14.3 HRMS (ESI TOF, M+H + ) m/z calcd. for C 27 H 37 NO 2 S 2 H 472.2338, found 472.2357. Scheme 2 22 Decarboxylative cross coupling using the potassium ProDOP dicarboxylate salts 30 and 31 Potassium 5,5' (1,4 phenylene)bis( N dodecyl 3,4 (propylene 1,3 dioxy)pyrrole 2 carboxylate) ( 30 ) To a 50 mL round bottom flask containing a stir bar was added diester 6 (0.262 g 0.3145 mmol), THF (6 mL) and ethanol (6 mL) After the solid dissolved, 3.8 mL of [5M] KOH (1 9 mmol, 60 equiv.) was added, and the mixture was degassed by bubbling argon for 10 min The flask was equipped with a condenser and the reaction mixture was heated to 55 60 C with strong stirring under argon for 72 hours The reaction mixture was filt ered using glass wool (to remove traces of

PAGE 63

63 palladium black), and then the organic solvents (THF and ethanol) and most of the water were carefully removed in a rotary evaporator at 25 C which produced precipitation of the potassium decarboxylate salt. The resulting solid was filtered washed with slightly basic cold water, air dried for 5 minutes and washed with hexanes The pale yellow solid (hydrated) was then put under vacuum (0.1 mmHg) at 115 C for 72 hours The final product was isolated as a white s olid, 0.247 g, 92 % yield 1 H NMR (300 MHz, d 6 DMSO): H 7.24 (s, 4H), 4.23 (t, 4H, J = 6.9 Hz), 3.82 (dd, 8H, J = 5.9 Hz, J = 9.5 Hz), 1.97 (m, 4H), 1.32 0.90 (br, m, 40H), 0.84 (t, 6H, J = 6.5 Hz) FTIR (KBr, pellet) max (cm 1 ): 3395.5 (br, w), 2924.7 (s), 2853.5 (s), 1566.0 (s), 1 447.9 (s), 1417.5 (s), 1356.9 (s), 1081 (s), 1138.1 (w), 806.3 (m). Potassium 5,5' (3,4 (ethylene 1,2 dioxy)thiophene 2,5 diyl)bis(N dodecyl 3,4 (propylene 1,3 dioxy)pyrrole 2 carboxylate) (31 ) The reaction was performed using a similar procedure as for 30 Using 2.521 g of 14 (2.810 mmol), 54 mL of THF, 54 mL of EtOH, and 34 mL of [5M] KOH The workup was slightly modified as follows: After removal of the volatiles, the resulting gum like solid was filtered, washed with slightly basic cold water, and a ir dried for 10 minutes The pale yellow solid was subjected to vacuum overnight at room temperature; yielding an amber solid which was ground in a mortar, producing a fine yellow powder, 2.548 g, 99% yield 1 H NMR (300 MHz, d 6 DMSO): H 4.16 (m, 8H), 3 .83 (m, 8H), 1.97 (m, 4H), 1.39 0.09 (m, 40H), 0.84 (t, 6H, J = 6.5 Hz) 13 C NMR (75 MHz, d 6 DMSO): C 163.7, 138.3, 137.2, 137.2, 136.7, 120.2, 105.9, 105.9, 71.3, 71.0, 64.0, 34.6, 31.4, 31.4, 31.2, 29.1, 29.0, 29.0, 28.9, 28.6, 26.4, 22.0, 13.8 FTI R (KBr, pellet) max (cm 1 ): 3392.1 (m), 2924.2 (s), 2853.7 (s), 1580.8 (s), 1510.7 (m), 1462.0 (s), 1420.6, 1420.6 (s), 1358.6 (s), 1080.6, 954.9 (w), 806.9 (w).

PAGE 64

64 Synthesis of 5,5' (1,4 phenylene)bis( N dodecyl 2 (pyridin 4 yl) 3,4 (pr opylene 1,3 dioxy)pyrrole) ( 32 ) To a dry 50 mL round bottom flask containing a stir bar and under argon atmosphere was added compound 30 (0.233 g, 0.2725 mmol, 1 equiv.), 4 bromopyridine hydrochloride (0.1113g, 0.5723 mmol, 2.1 equiv.), anhydrous K 2 CO 3 ( 0.083 g, 0.600 mmol, 2.2 equiv.), n Bu 4 NBr (0.220 g, 0.6814 mmol, 2.5 equiv.), tri( o tolyl)phosphine (7 mg, 0.0229 mmol, 4 mol % ) and palladium(II) acetylacetonate (3.5 mg, 0.0114 mmol, 2 mol % ) The flask was equipped with an air cooled condenser then an i nlet vacuum adapter was connected to the top of the condenser and the system was purged with vacuum argon four times, then N methylpyrrolidone (6 mL, previously degassed) was added via syringe The system was then equipped with a silicon oil bubbler and t he reaction mixture was warmed to 70 75 C and stirred for 60 hours The reaction mixture was concentrated to ~1 mL in a rotary evaporator (at 80 C ), and then it was cooled to room temperature; partitioned between diethyl ether and water, and then washed with water (5x), brine (1x), and dried over Na 2 SO 4 The resulting crude was purified by chromatographic column on basic alumina using a solvent gradient from 1:0 to 0:1 Et 2 O:EtOAc as eluent; yielding 0.147 g of a yellow solid, 64% yield 1 H NMR (300 MHz CDCl 3 ): H 8.60 (d, 4H, J = 5.5 Hz ), 7.49 (s, 4H) 7.37 (d, 4H J = 5.5 Hz), 4.03 (dd, 8H, J = 5.0 Hz, J = 9.7 Hz), 3.78 (t, 4H, J = 7.0 Hz), 2.19 (m, 4H), 1.24 0.72 (br, m, 46H) 13 C NMR (75 MHz, CDCl 3 ): C 149.8, 139.6, 139.1, 137.7, 129.6, 129.4 123.9 (br), 123.0, 118.5, 72.3, 46.4, 34.8, 30.1, 29.8(br), 29.8(br), 29.6, 29.5(br), 29.5, 29.0, 26.2, 22.9, 14.3 HRMS (MALDI, sithianol matrix, M+H + ) m/z calcd. for C 54 H 74 N 4 O 4 H 843.5783, found 843.5765.

PAGE 65

65 Synthesis of 5,5' (3,4 (ethylene 1,2 dioxy)thio phene 2,5 diyl)bis(N dodecyl 2 (pyridin 4 yl) 3,4 (propylene 1,3 dioxy)pyrrole) ( 33 ) The reaction was performed using the same procedure as for 32 ; using 31 (0.250 g, 0.2725 mmol, 1 equiv.), 4 bromopyridine hydrochloride (0.1113g, 0.5723 mmol, 2.1 equiv.) anhydrous K 2 CO 3 ( 0.083 g, 0.600 mmol, 2.2 equiv.), n Bu 4 NBr (0.220 g, 0.6814 mmol, 2.5 equiv.), tri( o tolyl)phosphine (7 mg, 0.0229 mmol, 4 mol % ), palladium(II) acetylacetonate (3.5 mg, 0.0114 mmol, 2 mol % ) and 6 mL of NMP The product was isolated as a pale orange solid, 0.195 g (79% yield) 1 H NMR (300 MHz, CDCl 3 ): H 8.56 (d, 4H, J = 6.1 Hz), 7.31 (d, 4H, J = 6.2 Hz), 4.28 (s, 4H) 4.02 (m, 8H), 3.92 (t, 4H, J = 7.1 Hz), 2.16 (m, 4H), 1.40 0.89 (br, m, 40), 0.84 (t, 6H, J = 6.8 Hz) 13 C NMR (75 MHz, CDCl 3 ): C 149.8, 138.9, 138.6, 138.5, 138.2, 123.2, 118.4, 112.3, 106.8, 72.3, 64.8, 46.0, 34.8, 32.0, 30.6, 29.8, 29.7 (br), 29.6, 29.6, 29.5, 29.2, 26.6, 22.8, 14.2 HRMS (ESI TOF, [M+H] 2+ ) m/z calcd. for C 54 H 74 N 4 O 6 SH 2 454.2737, found 454.2743. Scheme 2 23 Decarboxylative cr oss coupling using the ProDOP monoacid 27 and 4,7 dibromobenzo[c][1,2,5]thiadiazole. Synthesis of 4,7 bis(N dodecyl 3,4 (propylene 1,3 dioxy)pyrrol 2 yl)benzo[c][1,2,5]thiadiazole ( 34 ) To a dry 25 mL round bottom flask containing a stir bar and under arg on atmosphere was added compound 27 (0.3 g, 0.8535 mmol, 2.5 equiv.), and finely ground anhydrous potassium bicarbonate (0.089 g, 0.8877 mmol, 2.6 equiv.) The flask was equipped with an air cooled condenser; an inlet vacuum adapter was connected to the t op of the condenser and the system was purged with vacuum

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66 argon four times, and then NMP (15 mL, previously degassed) was added via syringe The mixture was warmed to 35 C and stirred for 1 hour (vacuum was slightly applied several times to remove CO 2 and to help the neutralization process), and then 4,7 dibromobenzo[c][1,2,5]thiadiazole (0.100 g, 0.3414 mmol, 1 equiv), tri( o tolyl)phosphine (6.2 mg, 0.0205 mmol, 6 mol % ) and palladium(II) acetylacetonate (3.11 mg, 0.0102 mmol, 3 mol % ) were added The syst em was then equipped with a septum, and a bubbler (containing silicon oil), and the reaction mixture was warmed 80 82 C and stirred for 42 hours The solvent was removed in a rotary evaporator at 80 C The crude was dissolved in dichloromethane and was hed with water The dichloromethane was removed by rotary evaporation and the resulting crude was purified by chromatographic column on silica (previously neutralized with triethylamine); using a 2:1 e ther: h exanes mixture as eluent; yielding 0.112 g of a bright red oil (44% yield) 1 H NMR (300 MHz, DCM d 2 ): H 7.55 (s, 2H), 6.45 (s, 2H), 4.03 (t, 4H, J = 4.3 Hz), 3.96 (t, 4H, J = 4.8 Hz), 3.71 (t, 4H, J = 7.2 Hz), 2.13 (m, 4H), 1.67 0.98 (m, br, 40 H), 0.87 (t, 6H, J = 6.7 Hz) 13 C NMR (75 MHz, DCM d 2 ): C 54.9, 139.4, 138.0, 131.1, 123.8, 115.7, 108. 0, 73.1, 73.0, 48.9, 35.9, 32.5, 31.6, 30.2, 30.2, 30.1, 30.0, 29.9, 29.7, 27.1, 23.3, 14.5 HRMS (APCI, [M+H] + ) m/z calcd. for C 44 H 66 N 4 O 4 SH 747.4878, found 747.4876.

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67 CHAPTER 3 SYNTHESIS OF DIOXYPY RROLE BASED POLYMERS VIA DEHALOGENATION POLYCONDENSATI ON Dehalogenation Polycondensation As was mentioned previously, 2,5 dihalo 3,4 dioxypyrroles (dihalo XDOPs) tend to decompose or to oligomerize ; 32 consequently to take advantage of this type of chemical behavior, Walczak et al. explored this feature to generate polymers from diiodo XDOPs. 23 56 The deiodination polycondensation resulted a convenient methodology to synthesize XDOP based materials, and th e method was successfully applied to the synthesis of homopolymers 23 a nd both block and random copolymers. 56 A description of the method is shown in Scheme 3 1 The method is a three step synthesis, starting from the XDOP diacid 3 7 and requir ing the isolation and purification of the intermediate 3 9 T his d i iodo compound can be polymerized in bulk or using a suitable solvent. Scheme 3 1 Synthesis and polymerization of 2,5 diodo 3,4 dioxypyrroles previously reported by Walczak et al. 23 The research carried out by Walczak showed that the deiodination polycondensation effectively generates high molecular weight polymers and can be scaled up without the use of metals, oxidants solvents, or other additives Additi onally the methodology is aqueous compatible and t olerant to many functionalities allowing the synthesis of various type s of XDOP polymers The research presented here descr ibes a modified version of the deiodination polycondensation method. 23 This new

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68 methodology can not only be applied to the polymerization of the XDOP monomers that were previously reported by Walczak et al. 23 but also to new XDOP based monomers that cannot b e polymerized efficiently by the original approach A ttempt s to extend the deiodination polycondensation method to produce regioregular copolymers from discrete oligomers, such as the 3,4 propylendioxypyrrole (ProDOP) derivative 14 shown in S chem e 3 2 fai led The partial decarboxylation high reactivity and low solubility in aqueous base of 41 a hindered its utilization for the iododecarboxylation using triiodide T he partial loss of the carboxylic functionalities occurred during the hydrolysis of 14 and was confirmed by proton NMR, which showed that the reaction crude is approximately a mixture 24:6:1 of diacid 41 a monoacid 41 b and non substituted dioxypyrrole oligomer 41 c The partial decarboxylation occurred even if the hydrolysis was carried out at r elat ively low temperature (<40 ). Scheme 3 2 Polymerization attempt for a ProDOP based oligomer using the triiodide route. Due to the problems applying the Walczak method to this new XDOP system it was convenient to search for an alternative sour ce of electrophil ic iodide, and a s shown in Scheme 3 3, compound s 1 and 9 were employed as trial molecules C onveniently, it was found that the N halosuccinimides can produce the halo compound via electrophilic halogenation on the 3,4 dioxypyrrole 1 and also by halo decarboxylation of the carboxylic acid 9

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69 Scheme 3 3 Halodecarboxylation and halogenation of two 3,4 propylenedioxypyrroles using N halosuccinimides. In order to obtain information about the degree of conv ersion of the halo decarboxylation, t he iododecarboxylation reaction using N iodosuccinimide (NIS) was run in a n NMR tube and the 1 H NMR signal was monitored throughout the reaction (Figure 3 1) The 1 H NMR experiment showed that t he iododecarboxylation t ook place in less than 2 hours, and full conversion was observed The monitoring of the reaction was carried out using the methylene of the C 12 H 25 chain and it was possible to observe that the reaction proceeded to high conversion with no byproducts pr esent apart from the N H succinimide and a small amount of the diodo ProDOP ( H 4.6 ppm) which formed from the diacid ProDOP that was present in the starting material The halodecarboxylation occurred considerably slower for the other N halosuccinimides N bromosuccinimide (NBS) and N chlorosuccinimide (NCS) requiring longer reaction times, and in these cases full conversion was not observed V arious byproducts were

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70 visible in the TLC with one of the byproducts being identified as the dimerization pr oduct. Figure 3 1 Proton NMR m onitoring of the degree of conversion of a ProDOP monoacid using NIS in DCCl 3 t = 1: reaction mixture ~ 1 minute after reactants were ad ded to the NMR tube at 25 t = 110 : the s ame reaction run for 110 minutes at 55 A test reaction using NIS and the oligomeric mixture 41 a c was carried out, and as shown in Scheme 3 4, acceptable molecular weigh ts were obtained in a 4 day reaction Scheme 3 4. In situ halo decarboxylation and dehalo p olycondensation of the oligomeric mixture 41a c The same reaction was carried out using NBS and NCS for three di fferent ProDOP carboxylic acids, and the results are shown in Table 3 1 Although som e of the reactions presented in Table 3 1 produced acce ptable molecular weig hts, these molecular weights can be considered too low to produce the desire d electronic

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71 properties; therefore, it was necessary to explore other alternative s for this type of polymerization Table 3 1 Polymerization of various ProDO P dicarboxylic acids via dehalogenation polycondensation using N halosuccinimides. entry monomer a X source polymer M n / M w (kDa) Yield (%) a 1 NIS NBS NCS 44 a X = I: 7.7 / 13.6 44 b X = Br: 6.3 / 8.9 44 c X = Cl: 5.0 / 6.3 71 b 83 b 39 b 2 NIS NBS NCS 45 a X = I: 6.9 / 17.4 4 5b X = Br: 0.9 / 1.1 4 5c X = Cl: 1.1 / 1.5 60 76 79 3 NIS 47 X = I: 3.7 / 5.2 31 a The yields were calculated using the equation reported previously, 23 and based on the potassium salt for entry 1 b The crude mixture was used for the polyme rization after acidic work up of the respective potassium salt. It was also found that the potassium ProDOP carboxylates can be also employed directly for the halo decarboxylation in combination with iodine A mo del reaction was carried out, and it proc eeded in less than one hour when run at 60 (monitored by TLC) shown in Scheme 3 5 Scheme 3 5. Halo decarboxylation of the potassium ProDOP carboxylate 13 using iodine. Evaluation of this reaction for the synthesis of ProDOP based polymers showed higher mole cular weights than the N halosuccinimides and the results are presented in Table 3 2 Bromine was also evaluated for the polymerization of ProDOP carboxylates,

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72 but the method did not yield any promising result, and only oligomeric materials were received (Table 3 2) NIS in combination with the p otassium ProDOP dicarboxylate produced similar molecular weights as when the ProDOP diacid was employed ( Table 3 2, entry 1) Table 3 2 Polymerization of various ProDOP dicarboxylic acids via dehalogenation p olycondensation using various halogen sources. entry monomer a X source polymer M n / M w (kDa) Yield (%) a 1 I 2 Br 2 NIS 44 a X = I: 22.9 / 58.1 44 b X = Br: 1.3 / 1.9 44a X = I: 6.2 / 10 .0 67 66 20 b 2 I 2 Br 2 4 5a X = I: 15.9 / 35.7 4 5b X = Br: 0.9 / 1.9 55 48 3 I 2 47 X = I: 2.1 / 2.8 36 a The yields were calculated using the equation reported previously, 23 and based on the potassium salts b The polymer did not precipitate in methanol, so after removal of the solvent in vacuo the resulting crude was washed with water and methanol, and then dried under vacuum. The lower molecular weights when NIS was employed, instead of I 2 may be attributed to the reaction of the N H succinimide with the polymer end groups, which produces end capping of the polymer and causing the reaction to stop The polymerization s presented in Tables 3 1 and 3 2 can be run at relatively low temperature s (40 60 ) and the polymerization using NIS required longer reaction times (>4 days) than iodine (~48h) Additionally, due to the low s olubility of the potassium carboxylates, water was required for the reaction to proceed when I 2 was

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73 employed DCM or chloroform is a suitable solvent for this polymerization, since these solvents can dissolve both the polymer and the starting materials THF was also tested as solvent for the synthesis of 4 5a using NIS and similar results were observed ( M n = 6.2kDa M w = 10.4kDa) as when DCM or chloroform was employed. This method did not generate high molecular weights for N H X DOPs (entry 3, in Table 3 1 and Table 3 2), but it is logic to anticipate that the methodology can efficiently create polymers based on N alkyl 3,4 dioxypyrroles, and it can be also applied to different types of XDOP monomers Compared with the FeCl 3 oxidative polymerization, it is expected that the reaction displays higher functionality tolerance and lower sensitivity toward presence of water. After the reaction was stopped, the polymer needs to be de doped by addition of hydrazine; this is necessary since the reaction produces a polymer in its doped form It is worthy to note that since I 2 Br 2 and Cl 2 are released during the reaction, side reaction can occurs, such as halogenation, on the non substituted positions of aromatic rings if non substituted aromatic systems are employe d. In most cases, t he dehalopolycondensation started spontaneously, but if it did not occur, the pol ymerization reactions were initiated with U V light by irradiating the reaction vessel for one minute using a standard TLC U V lamp i.e. if N halosuccinimide s were employed The use of U V light for a few minutes (1 3 min.) catalyzes the initial cond ensation of the monomer which releases iodine, and which in turn oxidizes the oligomers that have just formed apparently initiating a chain growth polycondensat ion reaction; thus, the reaction seems to proceed by a combination of

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74 step and chain growth polycondensation mechanism. 57 Other feasible initiators can be an iodine c rystal or a catalytic amount of FeCl 3 Increasing the number of equivalents of NIS did not lead to polymers with higher molecular weights Additionally, if less than two equivalents of NIS was used a decrease in the molecular weight (M n = 4.9kDa, M w = 7 .7kDa for 4 5a ) was observed, also yielding a polym er with a dark appearance S ince typically poly XDOPs are colorless this could mean that polymer decomposition occurred, or impurities due to side reactions were present in the polymeric material The en d groups for these polymers are assumed to be halogens ; thus, all the molecules descri bed in T able 1 can perform as macromers or pre polymers These end groups can be further employed to produce higher molecular weight polymers or to make an additional de rivatization on the polymeri c chain The reaction shown in S cheme 3 6 not only proves that the polymer end groups are still active but also shows that polymer 44 a can behave as a macromer The pre polymer 44 a presented in S cheme 3 6 was prepared using NIS in DCM, purified by precipitation in MeOH after reduction with hydrazine, and stored under argon for several mo n ths The post polymerization reaction was carried out in dibromomethane, which has a higher boiling point than DCM, and the molecular weigh t increase was evident, improving from M n = 7kDa to M n = 11kDa. Scheme 3 6 Post polymerization of the polymer 44 a in dibromomethane. Solution doping was carried on the polymer 44a and as expected this polymeric materia l displayed interesting electrochromic properties Under solution doping the

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75 ProDOP EDOT ProDOP polymer ( 44a Figure 3 2 ) goes from highly transmissive in the neutral state, passing through faint blue black, to pale yellow (partially transmissive in the v isible region) in the oxidized state Cyclic voltammetry on ITO also showed that the polymer 44a has a low oxidation potential as expected for this electron rich system Unfortunately, the polymer delaminated from the ITO slide upon electrochemical oxida tion due to the high solubility of the oxidized polymer in propylene carbonate or acetonitrile Figure 3 2. a) Soluti on d oping of polymer 44a Using NOPF 6 [3mM] in DCM, and b) CVs of the same polymer spray cast onto ITO coated glass from solution (3 mg/ mL) in toluene, 0.1M LiBF 4 In general the deiodination polycondensation using iodosuccinimide or iodine proved to be a convenient and efficient polymerization method for the synthesis of ProDOP b ased polymers and oligomers I t was demo nstrated that the method can generate polymers with relatively high molecular weights, and it is logic al to think that the method can be applied to synthesize a variety of XDOP based materials under rela tively mild reaction conditions. General Stability of 3,4 Dioxypyroles It is possible to tune the dioxypyrrole properties by N and O substitution, but in general, d ue to their ele ctron rich nature XDOPs produce polymers with high electronic

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76 band gaps and low oxidation potentials; 24 however, these same desirable properties can render XDOP monomer syntheses difficult and time consuming and, thus, non 2,5 substituted XDO Ps must be handled carefully typically, under acid and oxygen free c onditions since they can decompose during reaction workup, purification, or storage. An example of the reactivity of 3,4 dioxypyrroles is presented in Scheme 3 7 The oligomer 28 which was made by decarboxylative cross coupling, decomposed after one wee k of storage under argon Apparently, water oxygen and acid traces (from chloroform decomposition, which was used to run the NMR) were able to produce this oxidation, via the mechanism proposed in S cheme 3 8 It is worthy to note that other plausible me chanisms may be also possible. Scheme 3 7 Unexpected oxidation of a ProDOP based molecule. Scheme 3 8 Proposed mechanism for the oxidation of a ProDOP based molecule. For most reacti ons pr esented in the studies in this dissertation a 3,4 dioxypyrrole containing a propylene bridge was employed (3,4 propylenedioxypyrrole, ProDOP)

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77 The propylene bridge is preferred since t he presence of the dioxepine ring offers higher stability toward oxidation to the pyrrole ring than the ethylenedioxy (EDOP) analog and the open chain substituents such as methoxy or hexyloxy. The relatively higher stability comes from the torsion generated in the seven member ring, which decreases the electron donati on from the oxygen atoms into the pyrrole ring, thus decrea sing the electron density of the heterocyclic ring In addition, ProDOPs also possess higher solubility than their EDOP analogs which is attribute d to the lower symmetry of the dioxepine ring, whi ch decreases the possibility of stacking. Experimental Section General Information All reagents and starting materials were purchased from known commercial sources and used without further purification, unless otherwise noted All reactions were carried out under argon atmosphere unless otherwise mentioned 1 H NMR and 13 C NMR spectra were collected on a Mercury 300 or Inova 500 Elemental analyses were carried out by the CHN elementary analysis service in the Chemistry Department of the University of F lorida FTIR measurements were carried out on a Perkin Elmer Spectrum One FTIR outfitted with a LiTaO 3 detector Gel permeation chromatography (GPC) was performed using a Waters GPCV2000 liquid chromatography system with an internal differential refracti ve index detector (DRI), at 40 C, and using two Waters Styragel HR THF was employed as the mobile phase at a flow rate of 1.0 mL/min Injections were made at 0.05 0.08 % w/v sample concentration Rete ntion times were calibrated against narrow molecular weight polystyrene standards.

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78 Experimental Procedures Monomer syntheses : Dioxypyrrole potassium salts and diacids were synthesized from their respective diesters as was previously described in Chapter 2 Synthesis of 5,5' (3,4 (ethylene 1,2 dioxy)thiophene 2,5 diyl)bis(N dodecyl 3,4 (propylene 1,3 dioxy)pyrrole 2 carboxylic acid) ( 41 ) Compound 31 (0.133 g, 0.1449 mmol, 1 equiv.), 10 mL of water, and 20 mL of DCM were added to a 100 mL separatory funnel, the mixture was shaken, and then 20 mL of [0.5M] HCl was added until most of the diacid was regenerated, the DCM layer was collected and the remaining aqueous layer was treated with 20 mL more of DCM and 10 mL of [0.5M] HCl The DCM fractions were washed with deionized water (3x), and then dried using sodium sulfate The DCM was removed in vacuo and the resulting sticky solid was put under vacuum for 2 hours The product was obtained as a mixture of approximately 24:6:1 of diacid 41 a monoacid 41b and non substituted dioxypyrrole oligomer 41c The product was used without further purification 1 H NMR (300 MHz, DCCl 3 ): H 9.77 (br, 2H), 6.33 (s, 0.22H), 6.31 (s, 0.08H), 4.26 (m, 12H), 4.05 (m, 4H), 3.71 (m, 1.44H), 2.26 (m, 4H), 2.13 (m, 0.75H), 1.62 (m, 5.47), 1.45 1.19 (br, m, ~ 40H), 0.86 (t, 6H, J = 6.6) 13 C NMR (75 MHz, DCCl 3 ): C 159.7, 141.9, 139.9, 135.4, 117.3, 107.7, 105.5, 73.8, 72.2, 64.8, 46.4, 34.3, 32.1, 31.7, 29.9, 29.8, 29.6, 29.5, 26.9, 22.9, 14.3. General polymerization method U sing N halosuccinimides Polymer 44a The crude diacid 41 (0.122 g, 0.1449 mmol, 1 equiv.) and 2 mL DCM (or chloroform) were added to a 25 mL round bottom flask, containing argon and equipped with a stir bar and a condenser The flask was cooled to 20 C and then N iodosuccinimide (0.069 g, 0.3043 mmol, 2.1 equiv., freshly recrystallized from dioxane) was added in one portion The reaction mixture was stirred for 10 minutes, slowly warmed to 60 C

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79 and stirred for 4 days The reaction mixture was cool ed to room temperature and carefully reduced with cold hydrazine monohydrate The resulting mixture was poured in methanol (120 mL) and stirred for 30 minutes (or until the polymer precipitated); the resulting solid was collected by vacuum filtration and washed with methanol, then it was dissolved in 2 mL of THF and precipitated into MeOH, filtered (osmotics, 20 m nylon membrane), and dried under vacuum A pale yellow solid, 80 mg, was received, 71% yield M n = 7675, M w = 13599 1 H NMR (300 MHz, DCCl 3 ) : H 4.22 3.40 (m, 16H), 2.18 (s, br, 2H), 2.09 (s, br, 2H), 1.70 1.00 (m, br,40H), 0.86 (m, 6H) 13 C NMR (125 MHz, DCCl 3 ): C 138.5(br), 137.9 (br), 137.2 (br), 112.6, 109.2 (br), 107.0, 72.3 (br), 64.7 (br), 45.7 (br), 35.3 (br), 32.2, 31.4, 31.0, 29.9 (br), 29.7, 29.6 (br), 28.9, 27.2 (br), 26.9, 26.8, 22.9, 14.3 Elemental Analysis calculated for C 44 H 66 N 2 O 6 S: C (70.36%), H (8.86%), N (3.73%) Found: C (70.32%), H (8.96%), N (3.52%). Polymer 44 b using N bromosuccinimide The reaction was carrie d out using the same procedure as for polymer 44 a 83% yield M n = 6300, M w = 8898 1 H NMR (300 MHz, DCCl 3 ): H 4.22 3.40 (m, 16H), 2.18 (s, br, 2H), 2.09 (s, br, 2H), 1.70 1.00 (m, br,40H), 0.86 (m, 6H) 13 C NMR (125 MHz, DCCl 3 ): 138.5 (br), 137.9 (br), 115.9 (br), 109.0 (br), 72.3, 64.7, 45.7, 35.3, 32.2, 31.0, 30.5, 29.9, 29.6, 29.2, 29.1, 28.9, 27.2, 27 .1, 27.0, 22.9, 14.3. Polymer 44 c using N chlorosuccinimide The reaction was carried out using the same procedure as for polymer 44 a 39% yield M n = 4978, M w = 6291 1 H NMR (300 MHz, DCCl 3 ): H 4.22 3.40 (m, 16H), 2.18 (s, br, 2H), 2.09 (s, br, 2H) 1.70 1.00 (m, br,40H), 0.86 (m, 6H) 13 C NMR (125 MHz, DCCl 3 ): 138.3 (br), 137.9 (br),

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80 137.2 (br), 119.8 (br), 109.1 (br), 109.0 (br), 72.3, 64.7, 45.7, 35.3, 32.2, 31.0, 30.7, 29.9, 29.7, 29.6, 29.1, 29.0, 27.3, 22.9 14.3. Polymer 45a using N iodosu ccinimide The reaction was carried out using the same procedure as for polymer 44a 60% yield M n = 13980, M w = 16781 1 H NMR (300 MHz, DCCl 3 ): H 4.38 3.20 (m, br, 6H), 2.15 (s, br, 2H), 1.74 0.95 (m, br, 20H), 0.86 (s, br, 3H) 13 C NMR (125 MHz, DCCl 3 ): 139.0, 109.1, 72.2, 46.1, 35.3, 32.2, 30.8, 30.1, 30.0, 29.9, 29.7, 29.6, 27.1, 22.9, 14.3 Elemental Analysis calculated for C 19 H 31 NO 2 : C (74.71%) H (10.63%) N (4.21%) Found: C (74.58%), H (10.73%), N (4.34%). Polymer 47 using N iodosuccinimide Reaction was carried out using the same procedure as for polymer 44a but the work up was modified as follows: after careful reduction with co ld hydrazine monohydrate, the reaction mixture was added dropwise to 75 mL of MeOH in an Erlenmeyer flask The mixture was stirred for 20 minutes, and then decanted The sticky oil that remained in the Erlenmeyer flask was washed with 40 mL of MeOH, then dissolved with THF and transferred to a vial, the solvent was removed in vacuo and the product was stored under argon The product was received as a brown black sticky solid, 31% yield M n = 3646, M w = 5222 1 H NMR (300 MHz, DCCl 3 ): H 9.68 8.60 (s, br, 1H), 4.37 3.57 (m, 4H), 2.04 1.09 (m, 18), 0.84 (m, 12) 13 C NMR (125 MHz, DCCl 3 ): C 131.1, 129.0, 40.3, 30.4, 29.2, 23.6 (br), 23.3, 14.3, 11.0. FTIR (NaCl, disc) max (cm 1 ): 3436.8 (w), 2958.0 (s), 2929.6 (s), 2873.6 (s) 2856.5 (s), 1717.5 (w), 1605.4 (m, br), 1464.4 (s, br), 1379.2 (s), 1343.8 (m), 1194.7 (m), 1112.1 (s), 1051.0 (s), 772.1 (w), 728.0 (w).

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81 General polymerization method using iodine Polymer 45 a The ProDOP potassium salt 29 (0.200 g, 0.4240 mmol, 1.0 e quiv.), iodine (0.226 g, 0.8905 mmol, 2.0 equiv), and 2 mL of DCM were added to a 25 mL round bottom flask, containing argon and equipped with a stir bar and a condenser The condenser was equipped with a septum and a silicon oil bubbler was connected to it The reaction mixture was stirred at room temperature for 10 minutes, and then 2 mL of deionized water was added The reaction was warmed up to 60 and stirred for 48 hours The reaction mixture was allowed to cool to room temperature and reduced b y careful addition of 2 mL of cold hydrazine monohydrate The entire crude was added into 75 mL of methanol and stirred for 15 minutes (or until the polymer precipitated) The resulting solid was collected by filtration (osmotics, 20 m nylon membrane), dissolved in 2 mL of THF and precipitated in 75 mL of MeOH The solid was collected by filtration (osmotics, 20 m nylon membrane) and subjected to Soxhlet extraction using MeOH for 16 hours The resulting solid was dissolved with dichloromethane (if the solution turned dark it was then reduced with various drops hydrazine monohydrate), concentrated to approximately 2 mL and precipitated into 50 mL of methanol The resulting solid was collected by filtration (osmotics, 20 m nylon membrane), and dried un der vacuum The product was obtained as a pale yellow solid, 0.072 g, 55% yield M n = 15909, M w = 35718 1 H NMR (300 MHz, DCCl 3 ): H 4.30 3.20 (m, br, 6H), 2.14 (s, br, 2H), 1.70 0.90 (m, br, 20H), 0.85 (s, br, 3H) 13 C NMR (125 MHz, DCCl 3 ): C 138.3 (br), 109.1 (br), 108.6 (br), 72.2, 72.1, 45.7, 35.4, 32.2, 31.3, 30.8, 30.0, 29.6, 27.4, 27.1, 22.9, 14.3 Elemental Analysis c alculated for C 19 H 31 NO 2 : C (74.71%) H (10.63%) N (4.21%), Found: C (74.71%), H (10.23%), N (4.59%).

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82 Polymer 44a using iodine The reaction was carried out using the same procedure as for polymer 4 5a 66% yield M n = 22875, M w = 58099 1 H NMR (300 MHz, DCCl 3 ): H 4.5 3.48 (m, br, 16H), 2.19 (s, br, 2H), 2.09 (s, br, 2H), 1.68 1.00 (m, br, 40), 0.86 (t, 6H, J = 6.9 Hz) 13 C NMR (125 MHz, DCCl 3 ): C 138.5, 138.0, 137.2, 109.2, 109.0, 107.0, 77.2, 72.3, 64.7, 45.6, 35.3, 32.1, 31.0, 30.5, 29.9, 29.9, 29.6, 29 .6, 14.3 Elemental Analysis calculated for C 44 H 66 N 2 O 6 S: C (70.36%), H (8.86%), N (3.73%) Found: C (70.99%), H (9.28%), N (3.13%).

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83 CHAPTER 4 FUSED AROMATIC DIKETONES A S PRECURSORS FOR THE SYNTHESES OF CONJUGATED MATERIALS Aromatic diketones are practi cal starting materials that can serve as synthons to generate a wide variety of monomers for the synthesis of conjugated oligomer s and polymers As shown in Scheme 4 1, th ese molecules can be converted into other molecules with different properties and characteristics (e. g. electron donors or electron acceptors), and most of these transformations can be done in one or two steps, demonstrating the versatility of these intermediates In this chapter, the synth ese s of various diketones (X = S, CH=CH, N=CH ), and some of their derivatives will be described Scheme 4 1 Various molecules that can be synthesized from fused aromatic diketones.

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84 T he band gap ( E g ) the energy difference between HOMO and LUMO is the key factor t hat establishes the electronic and conducting properties of conjugated polymers The donor acceptor approach has become one of the most powerful strategies for band gap engineering in conjugated polymers, therefore, to access new donor and acceptor mo lecules is highly convenient since it can lead to new conjugated systems with a wide range of band gaps. The donor acceptor motif produce s a decrease in the electronic E g of the conjugated polymer S uch a decrease of the electronic E g results from th e orbital interaction of the two monomeric units (donor and acceptor), which also generates a decrease of the b ond length alternation in the conjugated polymer H erein will be described the syntheses of various fu sed aromatic diketones, and how these fu sed aromatic diketones can be turned into different donor and acceptor molecules. Syntheses of Fused Aromatic Diketones Synthesis of B enzo[1,2 b:6,5 b']dithiophene 4,5 dione (BDTD) The most interesting diketone of the series presented in Scheme 1 is when X = S, benzo[1,2 b:6,5 b']dithiophene 4,5 dione (BDTD) The importance of this molecule is due to various factors : o n the one hand, there is a wide range of properties offered by the thiophene based materials, 17 and on other hand, the s ystem lends itself to facile post derivatization that can be carried out o n the thiophene rings (i. e. halogenation, on the carbonyl groups The synthesis of BDTD is also one of the most challenging of these syntheses, and the research presented in this section will show the efforts to synthesize this molecule, and its utilization as precursors for some of the molecules presented in Scheme 4 1 by different synthetic approaches

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85 The initial approach to make the Br 2 BD TD is presented in Scheme 4 2 T his approach failed since the compound 51 did not react using Friedel Crafts acylation An alternative approach is presented in Scheme 4 3 This route uses the readily available 2 bromothiophene as the starting material, and was based on previously reported literature procedure s 58 61 to produce the intermediate 52 Scheme 4 2 Failed synthesis of Br 2 BDTD via Friedel Crafts acylation Unfortunate ly, this route (Scheme 4 3) contains a considerable number of synthetic steps, and some of these steps produced low yields and required colum n purification, making the synthesis expensive and non suitable for a large scale production of the desire d product Additionally as shown in the final step in Scheme 4 3, the deprotection of the silyl compound (Me 3 Si) BDTD accomplished with standard deprotection methods (fluoride source or dilute acid) and only concentrated HCl could produce the cleavag e of the trimethylsilyl groups in the (Me 3 Si) BDTD However, concentrated HCl also causes the product to decompos e decreasing the overall reaction yield Scheme 4 3 Alternative route towards BDTD.

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86 Due to the aforemen tioned results, a new synthetic route was devised; this route a nd its results are shown in Scheme 4 4 This synthetic path is highly convenient; since the reaction c an be carried out in only two steps, in high yields and requiring no column purification ; additionally, it also uses the inexpensive and readily available 3 bromothiophene as starting material. Scheme 4 4 Two step synthesis of BDTD This synthetic route (Scheme 4 4) was initially discarded for two main reaso ns namely : the synthesis of the intermediate 5 3 could be quite challenging, and it was also believed that the oxidative polymerization of BDTD using FeCl 3 could occur Fortunately, BDTD did not polymerize an d the synthetic path resulted in an excelle nt alternative to produce this molecule (BDTD) The synthesis of the diketone 5 3 which is the key intermediate, was carried out using a modified literature procedure 62 then after 53 was isolated it was subjected t o oxidative ring closing using i ron trichloride in DCM In order to optimize the oxidative ring closing conditions, the reaction was run several times under different conditions i. e. different concentrations and temperatures, 25, 35 and 40 in dichlomethane (DCM) and monitored by TLC for several hours (1 24 h) which lead to the conclusion that the reaction must be carried out at room temperature for at least two hours, using three o r more equivalents of FeCl 3 or FeBr 3 to achieve high c onversion Higher temperature s and longer reaction times seemed to lead to partial

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87 chlorination (or bromination) of the final product, which was confirmed by high resolution mass spectrometry (HRMS), and if less than 2.5 equivalents of iron chloride was e mployed, it requires up to 24 hours of reaction and full conversion was not observed I t can be hypothesized that the polymerization of BDTD did not occur due to the low solubility of the reaction product Once 53 ring closes the product seems to form an adduct with HCl ( compound 5 4 Figure 4 1 ) which precipitated in the reaction as a green solid This adduct dissociates upon addition of water, and then the product can be isolated as a fluffy black purple solid (red in DCM) T he same adduct can be ge nerated by bubbling HCl gas to a dispersion of BDTD in DCM A dditional evidence of the aforementioned adduct is the fact that no or small amount s of HCl gas is release d during the reaction, meaning that somehow the hydrochloric acid is being trapped by th e reaction system Figure 4 1 Proposed BDTD HCl a dduct n = 1 2. As was mentioned previously, FeBr 3 was also employed as oxidant The main purpose of using this oxidant was to produce the ring closing of 5 3 and furth er bromination of BDTD in one pot The bromination took place, but unfortunately several byproducts were also observed, producing a low yield for Br 2 BDTD and a mixture of polybrominated products and oligomers of BDTD Since this latest approach failed, BDTD was isolated and purified, and then the bromination was carried out using N bromosuccinimide in N N dimethylformamide (DMF) in high yield (Scheme 4 5)

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88 Scheme 4 5 Bromination of BDTD. Synthesis of 3,8 D ibromo 1,10 phenanthroline 5,6 dione and 2,7 D ibromophenanthrene 9,10 dione The 3,8 dibromo 1,10 phenanthroline 5,6 dione ( 57 ) is a n interesting molecule due to the electron deficient feature of the two pyridinic rings, which makes it a potential candidate for the sy nthesis of electron acceptor molecules Since the 1,10 phenanthroline 5,6 dione is a n electron deficient system, bromination will take place slowly and under harsh conditions, leading to a mono and di brominated mixture of products T hus to circumvent this problem, the route presented in Scheme 4 6 was devised G iven that typical bromination of 1,10 phenatroline leads to 5,6 dibromo 1,10 phenanthroline ( 5 5 ) the reaction was carried out in the presence of sulfur monochloride (S 2 Cl 2 ) and using 1 chlorob utane as solvent and this way the 3,8 dibromo 1, 10 phenanthroline ( 56 ) was produced instead 63 After isolation and purification, 56 can be converted into 5 7 by oxidation with H 2 SO 4 /HNO 3 and KBr 64,65 It is noteworthy that it is import ant to place the two bromo atoms on the 3 and 8 positions of the phenanthroline 5,6 dione 5 7 to produce a continuous conjugated system. Sc heme 4 6 Synthesis of 3,8 dibromo 1,10 phenanthroline 5,6 dione ( 5 7 )

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89 Synthesis of 2,7 D ibromophenanthrene 9,10 dione As was mentioned for the 3,8 dibromo 1,10 phenanthroline 5,6 dione ( 5 7 ) it is important to maintain a continuous conjugation of the s ystem in phenanthrene based diketones ; therefore 2,7 dibromophenanthrene 9,10 diones ( 5 9 ) are more useful than 3,6 dibromophenanthrene 9,10 diones ( 5 8 ) for some applications Most common brominating reaction conditions for phena n threne 9,10 dione ( n itrobe nzene/Br 2 /organic peroxide) 66 produce 3,6 substitution ( compound 58 ) shown in S cheme 4 7 but by using the same reaction conditions employed for fluorenone (H 2 SO 4 /Br 2 ) 67,68 it is possible to generate the 2,7 substituted phena n threnedione ( 59 ) in acceptable yield s Scheme 4 7 Synthesis of 2,7 dibromophenanthrene 9,10 dione ( 5 9 ) Synthesis of Acc eptor M olecules Synthesis of P henanthro[9,10 d]oxazole The synthesis of this compound was found in an attempt to make the phenanthrene 9,10 diamine ( 60 ) using the Leuckart reaction (Scheme 4 8) 69 Expecting to get the diamino compound 60 ammonium formate was employed as the ammonium source and the reducing agent in N m ethylpyrrolidone (NMP) Instead of the expected product ( 60 ) t he reaction yielded the oxazole derivative 6 1 This resulted in an interesting method for the synthesis of fused benz oxazoles, and although, t he reaction was n ot appl ied to other diketones, i t is log ic al to think that it can be applied to produce analogue molecules from other fused diketones

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90 Scheme 4 8 Unexpected synthesis of phenanthro[9,10 d]oxazole ( 6 1 ) Synthesis of D ithieno[3',2':3,4;2'',3'':5,6]benz o[1,2 c][1,2,5]thiadiazole (DT BTD) and D ithieno[3',2':3,4;2'',3'': 5,6]benzo[1,2 c]furazan (DTBF) In order to make the diamino compound 6 2 BDTD was reacted with hydroxylamine hydrochloride to produce th e respective dioxime, which was then reduced with hy drazine with Pd on carbon as the catalyst, in a one pot reaction (Scheme 4 9) The diamine 6 2 was isolated and reacted with sulf ur monochloride in DMF leading to the desired electron acceptor molecule DT BTD this molecule was subjected to bromin ation, p roducing the compound Br 2 DT BTD in high yield. Scheme 4 9 Synthesis of Br 2 DT BTD. The conversion of BDTD into the dioxime was monitored by thin layer chromatography (TLC), and besides the expected dioxime 6 3 shown in Scheme 4 1 0 the formation of a strong fluorescent compound was ob served on the TLC plate and the intensity of that fluorescent compound increased over time; hence, the reaction was run longer (10 days) than normal ( ~24 hours) and DTBF was isolated in 62 % yield This compound was brominated using the same reaction conditions as for DT BTD to produce Br 2 DTBF In order to decrease the reaction time, the reaction was carried in a

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91 glass pressure vessel at 14 0 C and high conversion (~60%) was achieved in l ess than 72 hours. Scheme 4 1 0 Synthesis of Br 2 DTBF. This reaction presumably occurred t h rough the mechanism shown in Scheme 4 1 1 The dioxime 63 only formed when hydr oxylamine hydrochloride was employed which means that the acid plays an important role in the mechanism, not only in the formation of the dioxime but also in the tautomerization and further dehydration to form DTBF The tautomerization is favored due to the aromatization of the central phenyl ring It is noteworthy that if only hydroxylamine was used, it seemed to lead to an unstable compound, presumably the 5 nitrosobenzo[1,2 b:6,5 b']dithiophen 4 ol and/or 5 aminobenzo[1,2 b:6,5 b']dithiophen 4 ol, and this is the reason why hydroxylamine hydrochlorid e ( ClNH 3 OH ) was employed instead Scheme 4 1 1 Proposed mechanistic path for formation of DTBF.

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92 The same reaction can be run on Br 2 BDTD to produce the furazan derivative Br 2 DTBF Scheme 4 1 2 and this reaction path do es not require column purification, but the quality of the final product ( Br 2 DTBF ) is lower This assumption lower purity product was based on the fact that the color of the Br 2 DTBF made by this method (brown) differs from the one made by the route pres ented on Scheme 4 1 0 (bright yellow) D ue to the low solubility of Br 2 DTBF removal of impurities can be difficult. Scheme 4 1 2 Synthesis of Br 2 DTBF from Br 2 BDTD. Alternatively, it was also found that treatment of 6 3 or other dioximes with S 2 Cl 2 in DMF le a d s to a mixture of two compounds furazan and thiadiazole derivatives, shown in S cheme 4 1 3 and these results fit with a previous literature report 70 Scheme 4 1 3 Synt hesis of DTBF and DT BDT from the dioxime 6 3 The reduction of DTBF was attempted by various methods in order to obtain an alternative route towards the diamino compound 6 2 As shown in S cheme 4 1 4 the stability of the furazan ring toward s reducing agent s is quite high, and all the attempted conditions failed These results showed that the ring opening of the furazan moiety will require strong er reducing agent s but strong er reducing conditions could not be applied to Br 2 DTBF, since such reaction condit ions will cleave the bromo atoms making the route not practical

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93 Scheme 4 1 4 Failed reduction of DTBF under various relatively mild reaction conditions. The first reducing conditions that were tried for the reduction o f DTBF (Cs 2 CO 3 NMP) were found during the studies made for the decarboxylative cross coupling of 3,4 dioxypyrroles with Br 2 BTD (Chapter 2 of this dissertation) Optimization of the reaction conditions showed that the reduction of Br 2 BTD could be done i n N methylpyrrolidone ( NMP ) using cesium carbonate and traces of water, as shown in Scheme 4 1 5 Scheme 4 1 5 Reduction of Br 2 BTD, using cesium carbonate in NMP. Unfortunately, when th e s e reaction conditions were appl ied to Br 2 DTBF, cleavage of the bromo atoms occurred, as shown in Scheme 4 1 6 and no reduction of the furazan ring was observed. Scheme 4 1 6 Unexpected cleavage of Br 2 DTBF, using cesium carbonate in NMP.

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94 Reactivity o f Br 2 DTBF in the Stille C oupling A model reaction was carry out to test the reactivity of Br 2 DTBF in the Stille cross coupling As shown in Scheme 4 1 7 the reaction proceeded quickly and in high yield s proving that the DTBF unit can be easily include d into a conjugated system by using this or other suitable organometallic cross coupling s Scheme 4 1 7 Model Stille reaction for Br 2 DTBF. I n addition a Stille co polymerization was carried out on Br 2 DTBF and to overcome the low solubility that can result from the lack of solubilizing groups in the DTBF unit, a rando m approach was adopted A ratio 1:2:1 of Br 2 DTS:Me 3 Sn DTS:Br 2 DTBF was employed (Scheme 4 18) resulting in a final poly mer contain ing six solubiliz ing chains in the donor moiety per each acceptor DTBF unit which increas es the polymer solubility, and by extension its processibility Scheme 4 1 8 Random Stille co polymerization for Br 2 DTS, ( Me 3 Sn ) 2 DTS and Br 2 DT BF. The reaction presented in Scheme 4 18 proceeded in high yield, and the incorporation of the DTBF unit occurred to a high extent (i. e. based on the elemental analysis of the final polymer) The final polymer had a limited solubility in common

PAGE 95

95 solvents such as THF, DCM, and chloroform, but the material still could be processed from chlorobenzene or o dichlorobenzene. Reductive E therification of A romatizable D iketones Typically, to carry out the etherification of aromatic diketones, it is necessary to first carry out the reduction of the diketone, and then the etherification of the resulting product in a two step method T he reaction conditions presented in this section demonstrate that the reaction can be accomplished in only one step by using a suita ble solvent/base combination which allows the simultaneous reduction and etherification of diketones without needing Zn(0) or other metal s ; thus the conditions may be applied to various halo dik etones as well as to unsubstituted diketones (shown in S chem e 4 19 ) This reaction uses similar conditions applied to reduce Br 2 BTD shown in a previous reaction scheme (Scheme 4 5) The reaction produced acceptable yields (50 70 % ) when Br C 12 H 25 was employed, and these reaction yields are comparable to the lit erature reports us ing Zn(0) in the two step route, 71 where t he resulting donor molecules can be employed in a number of polymer syntheses. Scheme 4 19 Reductive etherification of aromatizable diketones Experimental Section General Information All reagents and starting materials were purchased from commercial sources and used without further purification, unless otherwise noted All reac tions were carried under argon atmosphere and using oven dried glassware unless otherwise mentioned

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96 1 H NMR and 13 C NMR spectra were collected on a Mercury 300 MHz or an Inova 500 MHz High resolution mass spectrometry was performed by the spectroscopic services in the Chemistry Department of the University of Florida with a Finnigan MAT 95Q Hybrid Sector or a Bruker APEX II FTICR or Agilent 6210 TOF FTIR measurements were performed on a Perkin Elmer Spectrum One FTIR outfitted with a LiTaO 3 detector Thermogravimetric analysis (TGA) measurements were performed with a Perkin Elmer TGA 7 thermogravimetric analyzer Experimental Procedures Synthesis of 1,2 di(thiophen 3 yl)ethane 1,2 dione (53) The literature procedure 62 was modified A solution of 3 lithiumthiophene, labeled as Solution A was prepared as follows: 100 mL of 2.5 m olar n b utyllithium (0.250 mol) in hexanes was added via cannula to 250 mL of anhydrous THF, previously cooled to 78C The mixture was stirred for 10 minutes, and then 23.4 mL of 3 bromothiophene (40 .758 g, 0.250 mol) was added dropwise The mixture was stirred for ~150 minutes keeping the temperature at 78 C M eanwhile Solution B was prepared as follows: In a 3000 mL round bottom flask (equipped with stir bar and a septum) containing 1750 mL of anhydrous THF was added LiBr (21.713 g, 0.250 mol, 1 equiv.) and CuBr (35.863 g, 0.250 mol, 1 equiv.), the CuBr and LiBr mixture was stirred until all the salts dissolved, then this mixture was cooled to 40C or to lower temperature s Solution C: 9.66 mL of oxalyl chloride (14.280 g, 0.1125 mol, 0.45 equiv.) was dissolved in 250 m L of anhydrous THF in a 500 mL round bottom flask (previously equipped with a septum) and cooled to 40C or to lower temperature s Solution A was added via cannula to S olution B, and the mixture was strongly s tirred for ~5 minutes ; then the S olution C wa s slowly added via cannula The mixture was kept in the cold bath for 2 hours allowed to

PAGE 97

97 warm up to room temperature, and quenched with 100 mL of saturated NH 4 Cl (aq.) The THF was removed by rotary evaporation, and ~ 4 00 mL of ethyl acetate was added to the resulting mixture, which was then transferred to a separatory funnel and washed with saturated NH 4 Cl(aq.) (3x, 150 mL), water (2x, 100 mL), and brine (1x, 100mL) Hexanes (300 mL) was added to the o rganic mixture, and the mixture was dried with Na 2 SO 4 and then filtered trough a short path of silica (the silica was flushed with hexanes:diethyl ether 1:1 to recover the entire product) The organic solvent s were completely removed by rotary evaporation, and then the resulting yellow solid was strongly s tirred in ~80 mL of a mixture 1:10 of diethyl ether:pentanes (or 1:10 diethyl e ther: hexanes), until all the solid chunks turned into a small powder The resulting fine solid was filtered in a Buchner funnel washed with cold pentanes, and then air dried The organic solvent of the remaining filtrate w as removed by rotary evaporation and the procedure (diethyl ether:pentanes treatment) was repeated with the resulting solid but using smaller amounts of the solvent mixture (this procedure was repeated three times total) The resulting solids were collected an d subjected to vacuum to remove solvent traces Alternatively, the solid can be purified by column chromatography (silica, and 1:3 of diethyl ether:hexanes ) A pale yellow solid was isolated 18.147 g 72.6% yield 1 H NMR (500 MHz, CD 2 Cl 2 ): H 8.43 8.30 (m, 2H), 7.78 7.66 (m, 2H), 7.48 7.35 (m, 2H) 13 C NMR (125 MHz, CD 2 Cl 2 ): C 185.9, 137.8, 137.6, 127.7, 127.1 HRMS (ESI TOF, M+Na + ) m/z calcd. for C 10 H 6 O 2 S 2 244.9701 found 244.9696 Benzo[1,2 b:6,5 b']dithiophene 4,5 dione (BDTD) To a 500 mL Erlenmeyer flask, equipped with a stir bar and an inlet adapter and containing 250 mL of DCM was added anhydrous FeCl 3 (19.465 g, 120 mmol, 3 equiv.) T he mixture was stirred for a

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98 few seconds, and then the diketone 53 (8.8914 g, 40 mmol, 1 e quiv.) was added in one portion A silicon oil bubbler was connected to the inlet adapter, and the reaction mixture was stirred for 2 h at room temperature The mixture was quenched with ~100 mL of chilled water and stirred for 5 minutes more Afterward s DCM was removed by rotary evaporation The resulting solid was filtered and washed with plenty of deionized water and stirred in 200 mL of water until a fine powder was formed The solution was then filtered an d washed with plenty water The resultin g solid was air dried for 10 minutes and then washed with 200 mL of dieth yl ether and dried under vacuum T he resulting solid can be recryst allized from acetonitrile or purified as follow s : t he black solid was added to ~ 200 mL of DCM, stirred for 10 minut es, and then 100 mL of silica was added T he mixture was stirred until the solid was dispersed on the silica, and then the entire mixture was transferred to a chromatographic column containing a short path of silica The column was then flushed with a mi xture of diethyl ether:DCM [1:3] until all the black purple solid was recovered ; the solvent can be roto evaporated and recycled into the column, a green stain remains on the silica after the product is recovered After removal of the organic solvent, the resulting solid was stirred i n hot ether for 15 minutes, vacuum filtered, and then air dried The resulting black solid was dried under vacuum, 8.627 g, 97.8% yield 1 H NMR (5 00 MHz, CD 2 Cl 2 ): H 7.47 (d, 2H, J = 5.2 Hz), 7.26 (d, 2H, J = 5.2 Hz) 13 C N MR ( 12 5 MHz, CD 2 Cl 2 ): C 175.3, 144.5, 135.9, 128.1, 126.5 HRMS ( DART M+H + ) m/z calcd. for C 10 H 4 N 2 O 2 220.9726 found 220.9726 Synthesis of 2,7 dibromobenzo[1,2 b:6,5 b']dithiophene 4,5 dione (Br 2 BDTD) To a 250 mL round bottom flask equipped with a s tir bar a nd an air cooled condenser was added BDTD (2.2027 g, 10 mmol, 1 equiv), NBS (3.738 g, 21 mmol, 2.1

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99 equiv.), and DMF (100 mL) The mixture was heated to 65 70C, and stirred for 24 hours T he DMF was remo ved by rotary evaporation at 45 C The resulting solid was washed with hot water, filtered, and air dried The resulting solid was stirred in 60 mL of boiling acetonitrile for 15 minutes The mixture was allowed to cool to room temperature, and then it was placed in a refrigerator overnight The resulting crystals were collected by vacuum filtration, washed with acetonitrile, air dried, and put under vacuum for >2 hours to remove solvent traces A d ark purple micro crystalline solid was received, 3.621 g, 96% yield 1 H NMR (500 MHz, CDCl 3 ): H 7.46 (s, 2H) 13 C NMR (125 MHz, CDCl 3 ): C 172.8, 143.8, 135.6, 130.2, 114.8 HRMS (ESI TOF, (M+Na) + ) m/z calcd. for C 10 H 2 O 2 S 2 Br 2 : 400.7734, found m/z 400.7751. Synthesis of 3,8 Dibromo 1,10 phenanthroline (56) The synthesis was carried out accordin g to the literature procedure. 63 Synth esis of 3,8 Dibromo 1,10 phenanthroline 5,6 dione (57) The synthesis was carried out according t o the literature procedure for analog ous compound s 64,65 To a 50 mL round bottom flask was added 3,8 d ibromo 1,10 phenanthroline ( 56 ) (0.218 g, 0.6450 mmol, 1 equiv.), and KBr (0.768 g, 6.450 mmol, 10 equiv.) The flask was cooled to 0 C, and c oncentrated sulfuric acid (2 .4 mL) was added dropwise and then concentrated nitric acid (1.2 mL) was added The flask was equipped with a condenser and t he resulting mixture was heated for 2 h at 80 C The mixture was coo led to room temperature, and poured slowly into 2 00 mL of chilled water The resulting yellow solid was collected by filtration, and air dried The solid was dissolved with ethyl acetate and the resulting solution was dried over Na 2 SO 4 The ethyl acetate was removed by rotary evaporation, and the resulting sol id was washed with diethyl ether A bright yellow solid

PAGE 100

100 was obtained 74 mg, 31% yield 1 H NMR (300 MHz, CDCl 3 ): H 9.12 (s, 2H), 8.58 (s, 2H) 13 C NMR (75 MHz, CDCl 3 ): C 177.3, 157.8, 150.6, 139.7, 128.6, 123.8. Synthesis of 2,7 Dibromophenanthrene 9,10 dione (59) The reaction was modified from the literature procedure. 67, 68 Phenanthrene 9,10 dione (12 g, 57.6341 mmol ,1 equiv ) was suspended in 500 mL of concentrated sulfuric acid (in a 1000 mL round bottom flask, or in a 1000 mL Erlenmeyer flask ) NBS (9.350 g, 52.5 mmol, 2.1 equiv) was added in one portion and then the flask was equipped with a large stir bar or a mechanical stirrer The mixture was stirred a t room temperature for 3 hours The mixture was poured into 600 mL of ice/water and stirred for 5 minutes, and then the resulting solid was vacuum filtered in a fr itted funnel, washed with water, K 2 CO 3(sat.) water (plenty), and air dried for several hours The resulting orange solid was dissolved in 600 mL of amine free DMF (hot), a llow ed to cool to room temperature After 6 7 hours the resulting crystals were co llected by filtration, and washed with diethyl ether The remaining DMF solution was roto evaporated until more solid precipitated (~150 mL), then the DMF solution was heated to dissolve the solid again The mixture was allowed to cool to recover more pr oduct as orange crystals The resulting solids were collected together and stirred in hot toluene ( > 200 mL) The heterogeneous mixture was allowed to cool to room temperature, and the resulting solid was vacuum filtered a nd washed with toluene, then plac e under vacuum overnight ; alternatively the solid can be recrystallized from DMSO An orange solid was recovered 13.2 g, 62.6% yield 1 H NMR (300 MHz, DMSO d 6 120C ): H 8.19 (d, 2H, J = 8.6 Hz), 8.10 (d, 2H, J = 1.9 Hz), 7.94 (dd, 2H, J = 1.8 Hz, J = 8.5 Hz) 13 C NMR (75 MHz, DMSO, 90C ): C 176.7, 137.2, 133.2, 130.7, 127.9, 126.3, 122.3

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101 Phenanthro[9,10 d]oxazole (61) Phenanthrene 9,10 dione (0.560 g, 2.6896 mmol, 1 equiv.) ammonium formate (1.018 g, 16.1376 mmol, 6 equiv.), and 30 mL of NMP wer e added to a 100 mL Erlenmeyer flask The flask was equipped with an air cooled condenser and the mixture was warmed to 105 110C, and stirred for ~3h T hen the temperature was increased to 165C and the stirring was continued for 12 hours more The reaction mixture was allowed to cool to ~60 C and filtered (to remove insoluble byproducts ) The resulting NMP solution was cooled to room temperature and poured into water (75 mL), and then the resulting solid was collected by filtration, washed with wa ter and air dried The resulting beige solid was put under high vacuum 0.245g, 46% yield 1 H NMR (300 MHz, CDCl 3 ): H 8.72 (t, 2H, J = 7.5 Hz), 8.55 (d, 1H, J = 7.6 Hz), 8.34 8.20 (m, 2H), 7.85 7.60 (m, 4H) 13 C NMR (75 MHz, CDCl 3 ): C 151.5, 129. 7, 129.1, 127.8, 127.6, 126.9, 126.5, 126.3, 123.9, 123.6, 123.0, 121.2 HRMS ( APCI M+H + ) m/z calcd. for C 15 H 9 NO 220.0757 found 220.0763 B enzo[1,2 b:6,5 b']dithiophene 4,5 diamine (62) To a 250 mL round bottom flask, containing a stir bar and under argon atmosphere, was added BDTD (2 g, 9.0799 mmol, 1 equiv.), hydroxylamine hydrochloride (1.577 g, 2.5 equiv.), and 200 proof ethanol (100 mL) The flask was equipped with a condenser and the mixture was warmed to 75 80C, and stirred for 2 0 hours T he reaction mixture was cooled to room temperature, and 200 mg of 10% of Pd on activated carbon (Pd/C) was added An addition funnel containing a solution of hydrazine monohydrate ( 15 mL of N 2 H 4 H 2 O in 25 mL of EtOH) was placed on top of the condenser T he reaction mixture was warmed up to 65 C, and then the hydrazine solution was added dropwise for ~1h The reaction temperature was increased to 85 C and then the mixture was stirred for 48

PAGE 102

102 hours The mixture was allowed to cool to ~60 C and filtered ( by gravity filtration and the filter was washed with ethanol to recover the entire product) The solvent was removed by rotary evaporation, and the resulting solid was dispersed in water filtered, washed with plenty water and cold ethanol The result ing yellow solid was air dried for 1 minute placed under vacuum, and store d under argon In the event that the product ha d dissolved when washing with ethanol, it was recovered by removing the organic solvent from the filtrate and by repeating the filtra tion procedure A bright yellow solid was isolated 1.409 g, 70.4% yield 1 H NMR (300 MHz, CD 2 Cl 2 ): H 7.35 (q, 4H, J = 5.5 Hz), 3.85 3.52 (s, br, 4H) 13 C NMR (75 MHz, CDCl 3 ): C 130.8, 125.9, 125.6, 124.1, 120.9 HRMS (APCI [M + H + ] ) m/z calcd. fo r C 10 H 11 N 2 S 2 2 21 .0 202 found 221 .0 200 Synthesis of Dithieno[3',2':3,4;2'',3'':5,6]benzo[1,2 c][1,2,5]thiadiazole (DT BTD) To a 25 mL round bottom flask, equipped with a stir bar a septum and a bubbler and containing argon atmosphere was added DMF (2 mL) and sulfur monochloride (0.6 mL, 0.9801 g, 7.2624 mmol, 4 equiv.) The flask was cooled to 0C, then the mixture was stirred, and the diamino compound 62 (previously dissolved in 2 mL of anhydrous DMF) was added dropwise via syringe The mixture was allowed to warm to room temperature and stirred for 2 hours The reaction mixture was quenched with 15 mL of water, stirred for 5 minutes, vacuum filtered, and air dried for 5 minutes The resulting sticky solid was extracted with dichloromethane (DCM) b y grinding it with a spatula The resulting DCM solution was filtered to remove sulfur byproduct Then silica (~40 mL) was added to the DCM solution and then the DCM was removed by rotary evaporation The resulting silica was transferred to a filtratio n funnel (vacuum) containing a short path of silica, then sand was placed on top of the silica The silica

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103 was flushed with hot hexanes (~250 mL) TLC was taken frequently from the hexanes fractions to confirm that all the sulfur byproduct ha d been elute d, and then a new filtration flask was placed under the funnel The silica was flushed with a mixture 2:1 DCM: h exanes until all the yellow product ha d come out The solvent was removed by rotary evaporation and the resulting solid was recrystallized from hot ethanol (~50 mL) The fine yellow needles were collected by filtration, washed with ethanol, air dried and put under vacuum, 0.370g, 82% yield 1 H NMR (500 MHz, CDCl 3 ): H 8.00 (d, 2H, J = 5.3 Hz), 7.51 (d, 2H, J = 5.3Hz) 13 C NMR (125 MHz, CDCl 3 ) : C 150.8, 135.8, 129.3, 125.3, 124.4 HRMS (APCI M+H + ) m/z calcd. for C 1 0 H 4 N 2 S 3 248.9609 found 248.9616 Synthesis of 5,8 dibromodithieno[3',2':3,4;2'',3'':5,6]benzo[1,2 c][1,2,5]thiadiazole (Br 2 DT BTD) To a 250 mL round bottom flask, equipped with a stir bar and a condenser was added DT BTD (0.380 g, 1.2402 mmol, 1 equiv), c hloroform (100 mL), and bromine (0.14 mL, 0.436 g, 2.7284 mmol, 2.2 equiv.) The reaction mixture was warmed to 80 85C, and stirred for 12 hours The reaction mixture was c ooled to room temperature, and the resulting solid was filtered, washed with chlo roform, air dried and put under vacuum to remove solvent traces A bright yellow solid was recovered 0.460 g, 91.3% yield 1 H NMR ( 5 00 MHz, chlorobenzene d 5 95 C): 7.85 (s, 2H) 13 C NMR (12 5 MHz, chlorobenzene d 5 9 5 C): C 149.4, 135.4, 129.7, 126.4, 114.2 Dithieno[3',2':3,4;2'',3'' :5,6]benzo[1,2 c]furazan (DTBF) To a 150 mL glass pressure vessel, equipped with a stir bar, was added the diketone BDTD (0.778g, 3.5321 mmol, 1 equiv), h ydroxylamine hydrochloride ( 0.614g, 8.8302 mmol, 2.5 equiv.),

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104 and 70 mL of ethanol (200 proof) The vessel was equipped with its respective Teflon cap, and the mixture was stirred at 85C for 24 hours T he temperature was then increased to 140 C and the reaction mixture was stirred for 60 hours. The mixture was cooled to room temperature and transferred to a round bottom flask The solvent was removed by rotary evaporation, and the resulting solid was washed with water The solid was then purified by column chromatography (silica, 1:5 ethyl acetate:hexanes) The resulting solid was stirred in a mixture of hot di ethyl ether:hexanes 1:1 for 10 minutes The mixture was cooled to room temperature, filtered washed with the ethyl eth er:h exanes ( 1:1 mixture ) and air dried The remaining filtrate was roto evaporated, and the procedure was repeated with the remaining solid (two times) The solids were collected and dried under vacuum A yellow solid was received, 0.488 g (60% yield) Al ternatively, this compound can be made in a 1 0 0 mL round bottom flask, equipped with a condenser, at 85C for 10 days 1 H NMR (300 MHz, CDCl 3 ): H 7.91 (d, 2H, J = 5.3 Hz), 7.56 (d, 2H, J = 5.3 Hz) 13 C NMR (75 MHz, CDCl 3 ): C 146.0, 137.3, 126.5, 124.3, 122.7 HRMS (E I, M + ) m/z calcd. for C 1 0 H 4 N 2 O S 2 231.9765 found 231.9762 Synthesis of 5,8 dibromodithieno[3',2':3,4;2'',3'':5,6]benzo[1,2 c]furazan (Br 2 DTBF) The reaction was carried using the same procedure as for Br 2 DT BTD A bright yellow solid w as received, >65% yield 1 H NMR (300 MHz, chlorobenzene d 5 90C ): 7.62 (s, 2H) 13 C NMR (75 MHz, chlorobenzene d 5 90C ): C 144.7, 136.9, 126.8, 123.1, 115.2 Synthesis of Br 2 DTBF from Br 2 BDTD. The reaction was carried out using the same procedure as for DTBF using 1.6545 mmol of Br 2 BDTD T he work up was modified as follows: the reaction was cool ed to room temperature, and the solvent

PAGE 105

105 removed by rotary evaporation The resulting solid was filtered and washed with water and acetone The resulti ng solid was air dried and stirred in 100 mL of hot tetrahydrofuran (THF), and filtered when still hot The remaining residue was treated again with 100 mL of hot THF The THF filtrates were roto evaporated, and the resulting solid was stirred in aceton e (~15 mL) for 30 min, filtered, washed with acetone, and air dried A pale brown solid was received in 61.5% yield. Synthesis 5,8 bis(4 hexylthiophen 2 yl) DTBF (66) To a 25 mL Schlenk flask, containing a stir bar and argon atmosphere, was added ( 4 he xylthiophen 2 yl)trimethylstannane (51 mg, 0.1538 mmol, 3 equiv.), Br 2 DTBF (20 mg, 0.0513 mmol, 1 equiv.), Pd 2 (dba) 3 (0.5 mg), and P( o tol) 3 (0.5 mg) The flask was purged with vacuum argon three times, and 1.5 mL of chlorobenzene (previously degassed) w as added The mixture was warmed to 105 C, and stirred for 12 hours The reaction mixture was cooled to room temperature and plenty me thanol was added until the product precipitated The resulting solid was filtered, washed with methanol, air dried, d iss olved with DCM and filtered through a short path of silica The DCM was removed by rotary evaporation and the resulting solid was washed with methanol, and dried under vacuum, affording 17.2 mg of an orange solid (>60% yield) 1 H NMR (300 MHz, CDCl 3 ): H 7.83 (s, 2H), 7.14 (s, 2H), 6.93 (s, 2H), 2.61 (t, 4H, J = 7.6 Hz), 1.70 1.61 (m, 4H), 1.43 1.25 (m, br, 12H), 0.91 (t, 6H, J = 6.4 Hz) 13 C NMR (75 MHz, CDCl 3 ): C 145.7, 144.8, 138.9, 135.5, 134.9, 126.9, 123.1, 121.2, 119.2, 31.9, 30.6, 30.5, 2 9.2, 22.8, 14.3 HRMS (APCI, [M+H] + ) m/z calcd. for C 30 H 32 N 2 OS 4 565.1470, found 565.1483.

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106 Synthesis of polymer 67 The synthesis was carried out using the same procedure as for 66 in a scale of 0.13 mmol of Br 2 DTBF, using a ratio 1:2:1 of Br 2 DTS :( Me 3 S n ) 2 DTS:Br 2 DTBF and Pd 2 (dba) 3 (1 mol%), P( o tol) 3 ( 3 mol% ) and chlorobenzene (7 mL) The reaction was run for 7 days at 115 C, then 5 mL of chlorobenzene, and a scoop of diethylammonium diethyldithiocarbamate were added The mixture was stirred for 15 minutes and added dropwise into 300 mL of MeOH The resulting solid was filtered (osmotics, nylon membrane, 20 m), and washed with acetone The resulting solid was transferred to a cellulose thimble and purified by Soxhlet extraction, using MeOH (12 hours), a cetone (12h), h exanes (6h), DCM (6h), and chlorobenzene The resulting chlorobenzene solution was concentrated to ~15 mL and then precipitated dropwise into 200 mL of methanol The resulting solid was filtered (osmotics, nylon membrane, 20 m), air dried for 5 minutes and dried under vacuum overnight Elemental a nalysis calculated for C 82 H 110 N 2 O S 8 Si 3 : C ( 66 52 %) H ( 7 49%), N ( 1.89 %) Found: C ( 65 08 %), H ( 7.8%), N ( 1.43 %). Synthesis of 2,7 dibromo 4,5 bis(dodecyloxy)benzo[1,2 b:6,5 b']dithiop hene (69) To a 25 mL round bottom flask, equipped with a stir bar and an air cooled condenser, was added Br 2 BTDT (0.150 g, 0.3968 mmol, 1 equiv.), dodecylbromide (0.297 g, 1.1903, 3 equiv.), K 2 CO 3 (0.219, 1.5872 mmol, 4 equiv.), and anhydrous N,N dimeth ylformamide (5 mL) The reaction mixture was stirred at 65C for 24 hours, cooled to room temperature, and poured into 50 mL of water The resulting solid was filtered, washed with water, and purified by column chromatography (silica, 1:8 hexanes:diethyl ether) A white solid was received, 0.174 g, 61% yield 1 H NMR ( 5 00 MHz, CDCl 3 ): H 7.44 (s, 2H), 4.12 (t, 4H, J = 6.7 Hz), 1.83 1.75 (m, 4H), 1.52 1.46

PAGE 107

107 (m, 4H), 1.40 1.20 (m, 32H), 0.89 (t, 6H, J = 6.9 Hz) 13 C NMR (125 MHz, CDCl 3 ): C 143.0, 13 4.4, 129.2, 124.9, 113.0, 74.6, 32.2, 30.6, 29.92, 29.87, 29.8, 29.7, 29.6, 26.3, 22.9, 14.3.

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108 CHAPTER 5 PERSPECTIVE AND OUTL OOK Synthetic methodologies played a vital role in the development and understanding of conjugated polymers, and this is understa ndable given the fact that the n ew synthetic developments ha d led to numerous ways to produce new conjugated polymers not only with the desired physical and electronic properties but also with high processability When the synthetic metals revolution s tarted in the mid seventies, few synthetic tools were available to carry out such a task, but nowadays, polymer scientists possess new tool sets that allow us to construct new polymeric materials, with improved purities and higher molecular weights Curre ntly, it is possible to synthesize almost any imaginable molecule allowing us to correlate our experimental data with our theoretical knowledge Unfortunately, in many cases, scientists forget that their role as scientific researchers is to explore, and to understand the different phenome na that the universe put in front of them, and in this way to develop new solutions for the common good N ow conjugated polymer r esearch has evolved more into a competition than in to a science and the lack of original ity seems to be a widespread trend in our field The work presented herein has shown how emerging synthetic methodologies can be applied to produce new organic materials, and provided a new toolset to develop 3,4 dioxypyrrole based conjugated materials (Chapter s 1 and 2) Additionally, it has been shown how the same monomeric unit can be slightly modified to generate a variety of new mole cules with different properties i e. the donors and acceptors shown in Chapter 4 The ir electron rich nature and tun ability are the two features that make 3,4 dioxypyrroles (XDOPs) attractive for applica tions in organic electronics, and due to this

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109 electron rich nature XDOPs can produce polymers able to combine high electronic band gaps with low oxidation potentials A lso due to their electron rich nature however, XDOPs must be handled carefully, since they can easily decompose during reaction workup, purification, or storage. It is clear now that 3,4 dioxypyrroles have been underutilized and this is logical given t he fact that so far, we have had a limited amount of tools to include this moiety into a conjugated material While the m onomer synthesis has probably been the most limiting factor in the progress of XDOP and PXDOP research the work presented herein a ttempts to complement the available toolset of synthetic methodologies and allow s for the derivatization of XDOPs and the synthesis of PXDOPs The studies of the decarboxylative cross coupling on 3,4 dioxypyrroles shown in Chapter 2 demonstrated the versat ility of this methodology for molecules with a tendency to undergo decarboxylation It is well known that molecules such as 3,4 dioxytiophenes and 3,4 dioxyfurans can also undergo decarbo xylation, therefore, it is understandable to envision that the decar boxylative cross coupling methodology may be expanded to these molecules too The decarboxylation temperature for 3,4 dioxytiophenes and 3,4 dioxyfurans are higher than for 3,4 dioxypyrroles, so future work will require model reactions to determine if the methodology is suitable for these molecules. Chapter 4 has shown how aromatic diketones can be derivatized to produce various acceptor and donor molecules, giving us access to a new molecular kit that can be combined with a wide variety of other availab le molecules These new fused systems may lead to new materials with higher electron and hole mobilities and unique

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110 electronic band gaps three important elements in a conjugated polymer It is also clear that the solubility of the polymers gener ated f rom these molecules may be relatively low T herefore, in order to surpass this problem various approaches need to be employed for example, using a ran dom reaction approach, as shown in S cheme 4 18, or using effective solubilizing groups in the donor mol ecule, or by synthesizing the same molecules containing various solubilizing groups in the aromatic rings.

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111 LIST OF REFERENCES (1) Letheby, H. J. Chem. Soc., Trans. 1862 15 161 163. (2) Inzelt, G. In Conducting Polymers ; Springer Berlin Heidelberg: 2008, p 265 269. (3) McNeill, R.; Siudak, R.; Wardlaw, J. H.; Weiss, D. E. Aust. J. Chem. 1963 16 1056 1075. (4) Bolto, B. A.; Weiss, D. E. Aust. J. Chem. 1963 16 1076 1089. (5) Bolto, B. A.; McNeill, R.; Weiss, D. E. Aust. J. Chem. 1963 16 109 0 1103. (6) Dall'Olio, A.; Dascola, G.; Varacca, V.; Bocchi, V. C. R. Acad. Sci., Paris, Ser. C 1968 267 433 5. (7) Natta, G. J. Polym. Sci. 1955 16 143 54. (8) Natta, G.; Mazzanti, G. Tetrahedron 1960 8 86 100. (9) The Nobel Prize in Chemist ry 1963. http://nobelprize.org/nobel_prizes/chemistry/laureates/1963/ (accessed: Oct 11 2011) (10) Natta, G.; Mazzanti, G.; Corradini, P. Atti accad. nazl. Lincei Rend. Classe sci. fis. mat. e nat. 1958 25 3 12. (11) Shirakawa, H.; Ikeda, S. Film and fibers of acetylene high molecular weight polymer. JP patent, 1970 34406, April 22, 1973. (12) Meshcheryakov, S. V.; Shvachkin, Y. A. Khim. Khim. Tekhnol., Tezisy Kraev. Nauchno Tekh. Konf. Molodykh Uch., Aspir. Spets. Khim. Kubani, 2nd 1973 2 206 7. (13) Ito, T.; Shirakawa, H.; Ikeda, S. J. Pol. Sci .: Pol. Chem. Ed 1974 12 11 20. (14) Shirakawa, H.; Louis, E. J.; MacDiarmid, A. G.; Chiang, C. K.; Heeger, A. J. J. Chem. Soc Chem. Comm 1977 578 580. (15) The Nobel Prize in Chemistry 2000. http://nobelprize.org/nobel_prizes/chemistry/laureates/2000/ (Accessed: Oct 11 2011) (16) Skotheim, T. A.; Reynolds, J. R. H andbook of Conducting Polymers : Processing and Applications ; Third ed.; CRC Press LLC, Boca Raton, F L 2007. (17) Skotheim, T. A.; Reynolds, J. R. Handbook of Conducting Polymers : Conjugated Polymers, Theory, Synthesis, Properties, an d Characterization ; Third ed.; CRC Press LLC, Boca Raton, FL 2007.

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112 (18) Skotheim, T. A.; Elsenbaumer, R. L.; Reynolds, J. R. Handbook of Conducting Polymers ; 2nd ed.; Marcel Dekker: New Y ork, 1998. (19) (a) Peierls, R. E. More surprises in theoretical phy sics ; Princeton University Press: Princeton, N.J., 1991 ; p 106 (b) Peierls, R. E., Quantum Theory of Solids ; Oxford Univ. Press: N.Y., 1955; p 229. (20) Salzner, U.; Lagowski, J. B.; Pickup, P. G.; Poirier, R. A. Synth. Met 1998, 96, 177 189. (21) Brd as, J. L.; Chance, R. R.; Silbey, R. Phys. Rev. B 1982 26 5843. (22) Heeger, A. J.; Kivelson, S.; Schrieffer, J. R.; Su, W. P. Rev. Mod Phys 1988 60 781. (23) Walczak, R. M.; Leonard, J. K.; Reynolds, J. R. Macromolecules 2008 41 691 700. (24) Wa lczak, R. M.; Reynolds, J. R. Adv Mater 2006 18 1121 1131. (25) Ateh, D. D.; Navsaria, H. A.; Vadgama, P. J. R. Soc. Interface 2006 3 741 752. (26) Schottland, P.; Zong, K.; Gaupp, C. L.; Thompson, B. C.; Thomas, C. A.; Giurgiu, I.; Hickman, R.; Abboud, K. A.; Reynolds, J. R. Macromolecules 2000 33 7051 7061. (27) Sonmez, G.; Schwendeman, I.; Schottland, P.; Zong, K.; Reynolds, J. R. Macromolecules 2003 36 639 647. (28) Thomas, C. A.; Zong, K.; Schottland, P.; Reynolds, J. R. Adv Mater 2 000 12 222 225. (29) Walczak, R. M.; Jung, J. H.; Cowart, J. S.; Reynolds, J. R. Macromolecules 2007 40 7777 7785. (30) Merz, A.; Schropp, R.; Dtterl, E. Synthesis 1995 1995 795 800. (31) Merz, A.; Meyer, T. Synthesis 1999 1999 94 99. (32) Merz, A.; Kronberger, J.; Dunsch, L.; Neudeck, A.; Petr, A.; Parkanyi, L. Angew. Chem. Int. Ed. 1999 38 1442 1446. (33) Ishiyama, T.; Takagi, J.; Yonekawa, Y.; Hartwig, J., F. ; Miyaura, N. Adv. Synth. Catal. 2003 345 1103 1106. (34) Dhanabalan, A .; Knol, J.; Hummelen, J. C.; Janssen, R. A. J. Synth. Met 2001 119, 519 522.

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113 (35) Jana, G. H.; Jain, S.; Arora, S. K.; Sinha, N. Bioorg. Med. Chem. Lett. 2005 15, 3592 3595. (36 ) Baudoin, O. Angew. Chem. Int. Ed 2007 46 1373 1375. (37 ) Gooen, L. J.; Rodrguez, N.; Gooen, K. Angew. Chem. Int. Ed. 2008 47 3100 3120. (38 ) Nilsson, M. Acta Chem. Scand. 1966 20 423 426. (39 ) Heim, A.; Terpin, A.; Steglich, W. Angew Chem 1997 109 158 159. (40 ) Heim, A.; Terpin, A.; Steglich, W. Angew. Chem. Int. Ed. 1997 36 155 156. (41 ) Peschko, C.; Winklhofer, C.; Steglich, W. Chem. Eur. J. 2000 6 1147 1152. (42 ) Myers, A. G.; Tanaka, D.; Mannion, M. R. J. Am Chem. Soc 2002 124 11250 11251. (43 ) Forgione, P.; Brochu, M. C.; St Onge, M.; Thesen, K. H.; Bailey, M. D.; Bilodeau, F. J. Am. Chem. Soc. 2006 128 11350 11351. (44 ) Gooen, L. J.; Deng, G.; Levy, L. M. Science 2006 313 662 664. (45 ) Moon, J.; Jeong, M.; Nam, H.; Ju, J.; Moon, J. H.; Jung, H. M.; Lee, S. Org Lett 2008 10 945 948. (46 ) Gooen, L. J.; Thiel, W. R.; Rodrguez, N.; Linder, C.; Melzer, B. Adv. Synth. Catal. 2007 349 2241 2246. (47 ) Miura, M.; Nomura, M. In Cross Coupling Reactions ; Springer Berlin / Heidelberg: 2002; Vol. 219, p 211 241. (48 ) Beaujuge, P. M.; Reynolds, J. R. Chem. Rev 2010 110 268 320. (49 ) Miyaura, N.; Suzuki, A. Chem. Comm un. 1979 19 866 867. (50 ) Miyaura, N.; Yamada, K.; Suzuki, A. Tetrahedron Lett. 1979 20 3437 3440. (51 ) Kotha, S.; Lahiri, K.; Kashinath, D. Tetrahedron 2002 58 9633 9695. (52 ) Arroyave, F. A.; Reynolds, J. R. Org. Lett 2010 12 1328 1331. (53 ) Shang, R.; Xu, Q.; Jiang, Y. Y.; Wang, Y.; Liu, L. Org. Lett 2010 12 1000 1003. (54 ) Gooen, L., J. ; Lange, P., P. ; Rodrguez, N.; Linder, C. Chem. Eur. J. 2010 16 3906 3909.

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114 (55 ) Bilodeau, F.; Brochu, M. C.; Guimond, N.; Thesen, K. H.; Forgione, P. J Org Chem 2010 75 1550 1560. (56 ) Reynolds, J. R.; Walczak, R. M. Catalyst free polymerization of 3,4 alkylenedioxypyrrole and 3,4 alkylenedio xyfuran. U S patent, 20070270571, 2007, 2007. (57 ) Walczak, R. M. Synthetic methodology as a basis for conducting polymer design. Ph. D. Dissertation, University of Florida, Gainesville, FL, 2006. (58 ) Khor, E.; Ng, S. C.; Li, H. C.; Chai, S. Heterocycles 1991 32 1805 12. (59 ) Nicolas, Y.; Blanchard, P.; Roncali, J.; Allain, M.; Mercier, N.; Deman, A. L.; Tardy, J. Org. Lett 2005 7 3513 3516. (60 ) Usta, H.; Lu, G.; Facchetti, A.; Marks, T. J. J. Am. Chem Soc 2006 128 9034 9035. (61 ) Hou, J.; Chen, H. Y.; Zhang, S.; Li, G.; Yang, Y. J. Am. Chem. Soc. 2008 130 16144 16145. (62 ) Babudri, F.; Fiandanese, V.; Marchese, G.; Punzi, A. Tetrahedron Lett 1995 36 7305 7308. (63) Saitoh, Y.; Koizumi, T. a.; Osakada, K.; Yamamoto, T. Can. J. Chem 1997, 75, 1336 1339. (6 4 ) Dickeson, J. E.; Summers, L. A. Aust. J. Chem. 1970 23 1023 7. (65 ) Yamada, M.; Tanaka, Y.; Yoshimoto, Y.; Kuroda, S.; Shimao, I. Bull. Chem. Soc. Jpn. 1992 65 1006 11. (66 ) Bhatt, M. V. Tetrahedron 1964 20 803 821 (67 ) Dewhurst, F.; Shah, P. K. J. J. Chem. Soc. C 1969 1503 1504. (68 ) Hanif, M.; Lu, P.; Li, M.; Zheng, Y.; Xie, Z.; Ma, Y.; Li, D.; Li, J. Polym Int 2007 56 1507 1513. (69 ) Leuckart, R. Ber. Dtsch. Chem. Ges. 1885 18 2341 2344. (70 ) Weinst ock, L. M.; Davis, P.; Handelsman, B.; Tull, R. J. J Org Chem 1967 32 2823 2829. (71 ) Phillips, K. E. S.; Katz, T. J.; Jockusch, S.; Lovinger, A. J.; Turro, N. J. J Am Chem Soc 2001 123 11899 11907.

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1 15 BIOGRAPHICAL SKETCH Frank A. Arroyave was born in Sev illa (Valle), Colombia, in 1976 He graduated with his B.S. in Chemistry from Universidad del Valle at Cali in 2004, where he worked in the research group of p rofessor Rodrigo Abonia in the area of heterocyclic chemistry In f all 2006, h e be gan graduate school at the University of Florida in Gainesville, Florida in the department of chemistry where he joined the g roup of p rofessor John Reynolds and focus ed his studies on organic and polymer chemistry.