Synthesis and characterization of the compounds with the derivatives of pyridine or schiff bases

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Title:
Synthesis and characterization of the compounds with the derivatives of pyridine or schiff bases
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xv, 180 leaves : ill., photos 28 cm. ;
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English
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Qian, Keping, 1943-
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Subjects

Subjects / Keywords:
Pyridine   ( lcsh )
Schiff bases   ( lcsh )
Crystallography   ( lcsh )
Ligands   ( lcsh )
Chemistry thesis Ph. D
Dissertations, Academic -- Chemistry -- UF
Genre:
bibliography   ( marcgt )
non-fiction   ( marcgt )

Notes

Thesis:
Thesis (Ph. D.)--University of Florida, 1991.
Bibliography:
Includes bibliographical references (leaves 174-179).
Statement of Responsibility:
by Keping Qian.
General Note:
Vita.

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University of Florida
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All applicable rights reserved by the source institution and holding location.
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Full Text











SYNTHESIS AND CHARACTERIZATION OF THE COMPOUNDS
WITH THE DERIVATIVES OF PYRIDINE OR SCHIFF BASES















BY

KEEPING QIAN


A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY

UNIVERSITY OF FLORIDA


1991



































TO MY PARENTS















ACKNOWLEDGMENTS


I would like to take the opportunity to thank my

supervisor Dr. Gus J. Palenik for his leadership and encou-

ragement over the years. This project could not have been

completed without the valuable knowledge and recommendation

that Dr. Palenik has offered.

I would also like to thank Dr. William M. Jones, Dr.

George E. Ryschkewitsch, Dr. James M. Boncella and Dr. Andrea

E. Tyler for being my supervisory committee. I am grateful

for their interest in the work.

There is not enough gratitude that could be offered to

Mrs. Ruth C. Palenik for her kindness and help.

Special thanks is offered to my parents for their

guidance through my early years and their love and support for

a lifetime.


iii















TABLE OF CONTENTS


Page

ACKNOWLEDGMENTS ................................... iii

TABLE OF CONTENTS ................................... iv

LIST OF TABLES...................................... vi

LIST OF FIGURES...................................... x

ABSTRACT ............ ................. ..... ..... .... xiv

CHAPTERS

ONE INTRODUCTION ................................. 1

Pyridine and Its Derivatives................. 1
Schiff Bases................................ 6
Helical Structure and Self Assembling........ 7

TWO REACTIONS OF CHLORAMINE WITH SOME METHYL
PYRIDINES .................................... 12

Historical View............................ 12
Synthesis of Chloramine with Some Methyl
Pyridines................ ................ 15
Crystal Structure of N-Amino(3,5-Dimethyl-
Pyridinium) ...... ......... .......... ..... 19
Discussion. ..... ...................... ..... 20

THREE METAL COMPLEXES WITH NONPLANAR MULTIDENTATE
LIGANDS ... ........ ... ..................... 40

Quadridentate Ligand......................... 40
Ligand................................... .... 43
Steriochemical Feature..................... 43
Synthesis of the Ligand..................... 45
Crystal Structure............................ 47
Metal Complexes.............................. 48
Copper(II) Complex......................... 48
Iron(III) Complex.......................... 58
Description and Discussion................... 68
Nonplanar Ligand.......................... 68











Copper(II) Complex ........................ 86
Iron(III) Complex......................... 96
Nonplanar Geometries....................... 108

FOUR METAL COMPLEXES OF AN INORGANIC DOUBLE
HELIX ".......... ....................... 110
Inorganic Double Helix....................... 110
Definition of Helicity...................... 111
Crystallographic Screw Axes and Helical
Symmetries..... ......... ....................... 113
Historical View............................. 114
Experimental Section....................... ... 119
Copper(II) Complex ......................... 119
Nickel(II) Complex.................. ....... 121
Description and Discussion.................. 133
Different Products in the Nickel System.... 142
Bis-tridentate Chelate.................... 145
Deprotonation of the Ligand................ 148
Geometry of the Polyhendrons Around
Metal Atoms................................ 152
Conformation of the Ligand................. 153
Herical Features of the Complexes.......... 161
Future ..................................... 167

APPENDICES

A REFERENCE CODES, R-VALUE AND REFERENCES FOR
THE 16 PYRIDINE ONLY" COMPOUNDS.............. 171

B REFERENCES CODES AND REFERENCES FOR THE
COMPOUNDS IN TABLE 3-27....................... 172

REFERENCES............................. ............... 174

BIOGRAPHICAL SKETCH................................... 180














LIST OF TABLES


Table Page

1-1 Approximate Number of Publications for Each
Fragment Containing Pyridine.................. 5

2-1 Melting Point and Elemental Analyses of the
Products of the Reactions with Chloramine..... 18

2-2 Crystal Data for [(CHnN2]C1 .................... 21

2-3 Final Positional Parameter (x 104) and Isotropic
Thermal Parameters (Axl03) for N-amino-3,5-
dimethylpyridinium chloride.................... 22

2-4 Selected Distances (A) and Angles (0) for
N-amino-3,5-dimethylpyridinium................ 23

2-5 Anisotropic Thermal Parameters (A2xl03) for
N-amino-3,5-dimethylpyridinium chloride........ 24

2-6 H-Atom Coordinates (x 104) and Isotropic
Thermal Parameters (Axl03) for N-amino-
3,5-dimethylpyridinium chloride................ 25

2-7 Distances (A) and Angles (o) Involving the
H Atoms for N-amino-3,5-dimethylpyridinium
Chloride..................... ...... ......... 26

2-8 The Effect of Atom Hybridization on Bond
Lengths of C-C Bond............................ 30

3-1 Crystal Data for [C2e0N202,] .................... 49

3-2 Final Positional Parameter (x 104) and
Isotropic Thermal Parameters (A2xl0O) for
2,2'-bis(salicylideneamino)biphenyl............ 50

3-3 Bond Distances (A) for 2,2'-bis
(salicylideneamino)biphenyl.................... 51

3-4 Bond Angles (0) and Hydrogen Bond for 2,2'-
bis(salicylideneamino)biphenyl................ 52








Table Page

3- 5 Anisotropic Thermal Parameters (A2xl10) for
2,2'-bis(salicylideneamino)biphenyl............ 53

3- 6 H-Atom Coordinates (x 104) and Isotropic
Thermal Parameters (Ax10 ) for 2,2'-
bis(salicylideneamino)biphenyl................. 54

3- 7 Crystal Data for [Cs26HiN2O2Cu] ................. 59

3- 8 Final Positional Parameter (x 104) and Isotropic
Thermal Parameters (A2xl03) for Complex of Cu
with (sal) bp .................................. 60

3- 9 Bond Distances (A) for the Cu[(sal),bp]
Complex....... ...... ......................... 61

3-10 Bond Angles (0) for the Cu[(sal)2bp]
Complex............... ................. .... 62

3-11 Anisotropic Thermal Parameters (A2xl03)
for the Cu[(sal)2bp] Complex................... 63

3-12 H-Atom Coordinates (x 104) and Isotropic
Thermal Parameters (A x103) for the
Cu[(sal)bp] Complex.......................... 64

3-13 Crystal Data for [C26H1NN2O2Fe]NO3. CH6H......... 69

3-14 Final Positional Parameter (x 104) and Isotropic
Thermal Parameters (A2xl03) for the
Fe[(sal)2bp]NO3 Complex......................... 70

3-15 Bond Distances (A) for the Fe[(sal),bp]NO3
Complex... ......................... 72

3-16 Bond Angles (0) for the Fe[(sal)2bp]NO,
Complex ................................. 73

3-17 Anisotropic Thermal Parameters (AVxl03) for
the Fe[(sal)2bp]NO, Complex.................. 75

3-18 H-Atom Coordinates (x 104) and Isotropic
Thermal Parameters (Axl0O) for the
Fe[(sal)2bp]NO, Complex........................ 77

3-19 Equations to Various Planes for 2,2-
bis(salicylideneamino)biphenyl................ 82

3-20 Distances (A) to Various Planes in TABLE 3-19
for 2,2'-bis(salicylideneamino)biphenyl....... 83

vii








Table Page

3-21 Equations to Various Planes for the
Cu[(sal)2bp] Complex ........................ 87
3-22 Distances (A) to Various Planes in TABLE 3-21
for the Cu[(sal),bp] Complex................. 88

3-23 Bond distances and Dihedral Angles (0) for
Various CuN2O, Complexes....................... 90

3-24 Equations to Various Planes for the
Fe[(sal)2bp]NO3 Complex...................... 97
3-25 Distances (A) to Various Planes in TABLE 3-24
for the Fe[(sal)2bp]NO, Complex ................ 98

3-26 A Summary of the Distortions for Some
Salicylidene Complexes........................ 100

3-27 The Bond Lengths (A) of Some Iron (III)
Complexes with Schiff-Bases and the
Spin-States (S)............................. 105

4- 1 Crystal Data for [Cu2(apsh)2] (NO3)2 ............ 122

4- 2 Final Positional Parameter (x 104) and
Isotropic Thermal Parameters (AVxl03)
for [Cu2(apsh),] (NO3)2.5H20...................... 123

4- 3 Bond Distances (A) for [Cu(apsh),] (NO3),...... 125

4- 4 Bond Angles (0) for [Cu2(apsh)] (NO3)2 ......... 126

4- 5 Anisotropic Thermal Parameters (A2x103) for
[Cu2(apsh) ] (NO3)2............................ 128
4- 6 H-Atom Coordinates (x 104) and Isotropic
Thermal Parameters (A xl03) for
[Cu2 (apsh),] (NO),2 ........................ ... 130

4- 7 Crystal Data for [Ni2(pcsh)] (C104)2............ 134

4- 8 Final Positional Parameter (x 104) and Isotropic
Thermal Parameters (A2xl03) for
[Ni (pcsh)2] (Clo4)2 ............................. 135
4- 9 Bond Distances (A) for [Ni2(pcsh)] (C104)..... 137

4-10 Bond Angles (0) for [Ni,(pcsh)2] (C104) ........ 138


viii









Table Pace

4-11 Structural Analysis for Ligand apsh........... 147

4-12 A Summary of the Bond Distances in Various
Protonated and Deprotonated Ligands ........... 150

4-13 Least-Squarea and Parameters in
[CU2(apsh)2] (NO)2 ............................. 154

4-14 Torsion Anngles (0) for apsh in
[CU2(apsh)] (NO)..................................... 157















LIST OF FIGURES


Figure Page

1- 1 Two Main Groups of the Compounds Containing
Pyridine Ring............................... 2

1- 2 Some Crown-type Polymers Containing
2,6-disubstituted pyridine units.............. 3

1- 3 Some Ylides Species......................... 4

1- 4 From Molecular to Supramolecular
Chemistry .................................... 8

1- 5 An Example of a supermolecule................ 9

2- 1 The Products of Chloramine(g) Through
Quinoline and Pyridine....................... 13

2- 2 Caffeine and Theobromine...................... 13

2- 3 O-Mesitylene-Sulfonylhydroxylamine............ 14

2- 4 N-amino(3,5-dimethylpyridinium) Chloride...... 15

2- 5 The Chloramine Generator...................... 16

2- 6 A View of the Crystal Structure of
[C7HN,]Cl Showing the Atomic Numbering
and Thermal Ellipsoids.......................... 28

2- 7 2,2-Dimethyltriazanium (a) and
l,1,l-Trimethylhydrazinium Chloride........... 30

2- 8 An Increase of C-N-C Angle in the Pyridene
rings of O-Substitution..................... 34

2- 9 Dipyridinium Oxalate-Oxalic acid
( one pyridinium is omitted).................. 35

2-10 1,1'-methylene-bis(4,4'-dimethyl-
aminopyridinium) ion.......................... 36

2-11 The Resonance Structure of [C1H22N4]2+.......... 37









Figure Page

2-12 Impossible Resonance Structures
for [C7HIN2]+ ................................... 39

3- 1 Possible Patterns for Quadridentate
Chelating Agents............................. 41

3- 2 The Examples of Nonplanar Quadridentate
Chelating Agents............................ 42

3- 3 Some Molecules with a Helical Conformation.... 44

3- 4 2,2'-bis-(Salicylideneamino)biphenyl
(sal)2bp....................................... 46

3- 5 A View of the Crystal Structure of
[C6H2,N20O,] Showing the Atomic Numbering
and Thermal Ellipsoids....................... 56

3- 6 A View of the Crystal Structure of
[C2eHN202Cu] Showing the Atomic Numbering
and Thermal Ellipsoids........................ 66

3- 7 A View of the Structure of [C26HigN2gOFe]NO3
Showing the Atomic Numbering and
Thermal Ellipsoids ........................... 79

3- 8 The Packing Pattern of
[C26H18N,2OFe]NO0.C6H ........................... 81
3- 9 2,2'-bis(2''-pyridylmethylamino)biphenyl...... 84

3-10 A Model of Strainless Tetrahedral
Arrangement for (sal),bp..................... 85

3-11 Three Chelating Rings in the Quadridentate
Schiff Bases.................................. 93

3-12 Four Possible Conformations in Seven-
membered Ring............................ ... 95

3-13 The Torsion Angles in the Seven-membered
Ring of the Copper Complex.................... 95

3-14 Five Possible Isomers in Metal Complexes
with Quadridentate Ligands.................... 99

3-15 Possible Models of Coordination
of Bridging Nitrate Group..................... 102









Figure Page

3-16 Another Fe(III) Complex Contaning
Seven-membered Rings......................... 107


3-17 The Torsion Angles in the Seven-membered
Ring of the Iron(III) Complex................ 108

4- 1 Right-handed Helix (P) and
Lift-handed Helix (M) ........... ........... 112

4- 2 Crystallographic Screw Axes
and Helical Symmetries ...................... 113

4- 3 (a) Zn2(dapp),;(one dapp omitted) (b) The
Feature of an Inorganic Double Helix.......... 115

4- 4 The DNA Double Helix......................... 116

4- 5 The Complex of Ag2[(R,S)-1,2-(6-R-Py-2-CH=N)2
Cyclohexane]2 (one ligand is omitted)........ 117

4- 6 The Nomenclature for Trigonal Complexes....... 117

4- 7 Oligobipyridine Ligands....................... 118

4- 8 A View of the Structure of [Cu,(apsh),]
Showing the Atomic Numbering and
Thermal Ellipsoids......................... 132

4- 9 A View of the Structure of [Ni2(pcsh),]
Showing the Atomic Numbering and Thermal
Ellipsoids (The positions of H atoms
have not determined)........................... 141

4-10 The Competitive Reactions of Hydrazides
with Ni(II) and Salicyladehyde................ 143

4-11 Possible Reactions of sadh with Ni(ii)
and 2-pyridinecarboxaldehyde.................. 144

4-12 Possible Patterns for Tridentate
Chelating Agents .............................. 145

4-13 Planar and Non-planar Configurations
for Tridentate Ligands....................... 146

4-14 Possible Conjugated Forms for
Deprotonated apsh Ligand..................... 149

4-15 Conformation of the apsh Ligand Chain......... 158

xii









Figure Pace

4-16 Molecular Conformations....................... 159

4-17 A View of the Crystal Structure of
the Double Stranded Helical Complex
[Cu2(apsh)]................................. ... 163

4-18 Another View of the Crystal Structure
of the Double Stranded Helical Complex
[Cua(apsh)2].............. ....................... 165

4-19 Braid, Thread and Crossing................... 167

4-20 3,3'-bis(salicylideneanino) Phenyl Ether...... 168


xiii














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

SYNTHESIS AND CHARACTERIZATION OF THE COMPOUNDS
WITH THE DERIVATIVES OF PYRIDINE OR SCHIFF BASES

By

Keping Qian

August 1991

Chairman: Gus J. Palenik
Major Department: Chemistry

Though the literature contains a huge number of

publications on pyridine and its derivatives, no crystal

structures of substituted N-amino pyridinium cations have

been reported. The reaction of chloramine with 3,5-lutidine

was carried out and formed to give the expected product.

The product crystallized in the space group P1 bar with

a=7.663(1), b=8.241(2), c=8.266(2) A; and a=116.75(2),

P=115.39(2), r=91.85(2).

The 2,2-bis-(salicylideneamino)biphenyl [(sal)2bp], a

Schiff base ligand, is a good nonplanar ligand. The space

group was found to be P1 bar with a=10.127(2), b=10.811(2),

c=11.409(3) A; and a=116.93(2), P=101.03(2), r=102.58(2)11.

The reaction of (sal)2bp with Cu(N03)2 results in a four

coordinate complex. The space group is Pnna with

a=16.949(3), b=13.188(3), and c=9.369(1) A. A similar

xiv








reaction of (sal),bp with Fe(N03)3 results in a six

coordinate complex. The space group is P 21/n with

a=10.887(4), b=18.462(5), c=14.142(3) A; and 8=98.27(2).

Both of the metal complexes are nonplanar.

The reaction of 2-acetylpyridine succinic acid dihydra-

zone (apsh) with Cu(NO,)2 generates a metal complex of an

inorganic double helix. The [Cu,(apsh),] (NO3), crystallizes

in the space group P 21/n with a=10.887(6), b=26.030(10),

c=17.263(5) A; and P=99.15(3). A similar complex of an

inorganic double helix is formed from the reaction of

Ni(C104)2 with 2-pyridine carboxaldehyde succinic acid

dihydrazone (pcsh). The space group of [Ni2(pcsh)] (C104)2

is C 2/c with a=22.172(11),b=14.867(6), c=32.589(9) A; and

P=112.52(3).

More extensive structural studies on the metal

complexes with an inorganic double helix are attractive in

order to correlate the variability of the chemical,

biological and structural properties and to understand the

self-assembling in supramolecular structures.















CHAPTER ONE
INTRODUCTION



Compounds which contain pyridine or its derivatives or

Schiff-bases as ligands have occupied a central role in the

development of coordination chemistry, organometallic

chemistry, and biochemistry. This situation is manifested by

the huge number of publications ranging from the purely

synthetic to modern physicochemical to biochemically relevant

studies of these compounds. A tremendous variety of stable

chemical species have been synthesized containing both metals

and nonmetals.


Pyridine and Its Derivatives


Of all the known heterocyclic systems, pyridine has

perhaps the greatest importance. This can be judged by the

variety and interest in its derivatives and their reactions

and by the volume of literature devoted to them.

Pyridine is a planar molecule which is less basic than

are the aliphatic amines. The pK, value of its conjugate acid

is 5.2. The electron pair in pyridine is located in an sp2

molecular orbital, whereas an sp3 orbital is utilized by

aliphatic amines. The high s-character accounts for the






2
decreased availability of electrons for reaction with a
proton.
There are over 4000 compounds containing a pyridine ring
in the 1989 release of the Cambridge Structural Database
(CSD). Obviously, people have paid great attention to
pyridine. Pyridine is capable of acting as either a i or a
ligand. The higher affinity of pyridine toward donation of
a electrons is due to its inherent structure. Pyridine forms
a dipole with the electron density localized on the nitrogen
atom. The lone pair of N-electrons has a geometry that makes
it easily accessible for donation to an atom in the resultant
compounds. These compounds can be roughly divided into two
main groups: pyridine as a neutral species; and pyridine as
a non-neutral species. (Figure 1-1)

o M


0 (Neutral)




N H C
I I+ I

(Non-neutral)




Figure 1-1 Two Main Groups of the Compounds
Containing Pyridine Ring






3
Pyridine and its derivatives have practical importance

in chemistry fields, such as organic chemistry, biochemistry,

co-ordination chemistry, both in experimental and theoretical

aspects. Some examples are illustrated here. The system of

pyridine hydrogen fluoride is of practical importance in

preparative organic chemistry, in wide use as a convenient

reagent for a variety of fluorination reactions.['1 Acyclic

ethers with 2,6-disubstituted pyridine units as a rigid donor

units are used in syntheses of crown-type polymers. (Figure

1-2)











N N N










N N L I NN



Figure 1-2 Some Crown-type Polymers Containing
2,6-disubstituted pyridine units






4
Crown-ethers have given remarkable results when used in
catalytic amounts for special application. They are used to
specifically complex cations. Such completing agents are of
particular interest as models for the transfer of ions across
the nonpolar membranes of biological system.' As an example
in theoretical application, pyridinium ylides (Figure l-3a)
have the special advantages to study the organometallic
compounds containing ylide carbon. Negatively charged ylide
carbon (see Figure 1-3) has an ability to coordinate to metal
ions.41 Although reactivities of photo-excited states of



Q \N- < (CHN-C' (N) -


a pyridinium ylide a nitrogen ylide a phosphorus ylide
a b c

Figure 1-3 Some Ylides Species


organometallic compounds have attracted much interest,1[
luminescent properties of ylides and their metal complexes
have been little investigated. Pyridinium ylides are unique
because the carbonion can be stabilized by a vacant r* orbital
of the pyridinium ring.[6
In view of the huge number of publications of pyridine
and its derivatives, we can say that the coordination of the
nitrogen atom of pyridine ring with oxygen, hydrogen, carbon







5
and metal atoms has been studied extensively. Table 1-1 Shows

the approximate number of publications for each fragment

containing pyridine ring in the 1989 release of the CSD.

Unfortunately, there are no structural data related to

the coordination of the nitrogen atom of pyridine ring with

a nitrogen atom. Therefore, we decided to study reactions of

pyridine and its derivatives with chloramine in an attempt to

prepare pyridine-N-N compounds. The structural information

of the coordination of N of pyridine ring with N will be

described and discussed in chapter two.



TABLE 1-1 Approximate Number of Publications
for Each Fragment Containing pyriding



H C M
I + I+ I
Fragment N o N N



M= Zn,Cd,Hg
Number 983 198 95


I -- N--






Number 48 119 19







6

Schiff Base

Schiff base ligands are very diverse. Schiff bases which

are effective as coordinating ligands usually bear a second

functional group, frequently -OH, but N and S donors are also

known. The site of condensation can be controlled so that a

five or six membered chelate ring can be formed upon reaction

with a metal ion.

Metal Schiff base complexes have been known since the

mid-nineteenth century,M and even before the general

preparation of Schiff base ligands themselves.181 However,

there was no comprehensive, systematic study until the

preparative work of Pfeiffer and associates.I'9,110 Since

Pfeiffer's initial contributions, the interest in Schiff-base

complexes has increased dramatically. Metal complexes of

Schiff bases have been of considerable interest in the

development of the coordination chemistry of chelate systems.

There are several types of Schiff-base chelate agents,

such as bi- and polydentate salicylaldimines, bi- and

polydentate P-ketoamines, and Schiff bases resulting from the

condensation of functionally substituted primary amines with

1,2-dicarbonyl compounds, etc. The complexes with

salicylaldimines are particularly attractive for systematic

stereochemical studies because of the relatively easy

synthetic variation of the nitrogen substituents, thereby

permitting varying degrees of steric strain to be incorporated

into the planar forms.







7

Recently, metal complexes of some quadridentate salicyl-

aldimines have been intensively studied because of their

special properties, such as the models of iron-oxo

proteins. 11"I21 Binuclear iron-oxo centers have emerged as

common structural components in the active sites of several

metalloproteins.111 More extensive structural studies on the

metal complexes with quadridentate Schiff bases which appear

to be nonplanar and/or helical are attractive in order to

correlate the variability of the chemical, biological and

structural properties and to understand the self-assembling

in supramolecular structures. The 2,2'-bis(salicylideneamine)

biphenyl ligand system has been chosen to address this

problem, because the ligand can form a nearly strainless N202

tetrahedron. 141


Helical Structure and Self Assembling


Molecular helicity is a fascinating property displayed

by chemical and biological macromolecular structures, such as

the a-helix of polypeptidesl611 and the helical conformation of

polymers.[16 The spontaneous formation of the double helix of

nucleic acids represents the self-assembling of a

supramolecular structure. Supramolecular chemistry is a very

active research field. The development in supramolecular

chemistry offers exciting perspectives at the frontiers of

chemistry with physics and biology.







8
Molecular chemistry of the covalent bond is concerned

with uncovering and mastering the rules that govern the

structures, properties, and transformation of molecular

species. Supramolecular chemistry may be defined as

"chemistry beyond the molecule," bearing on the organized

entities of higher complexity that result from the association

of two or more chemical species held together by

intermolecular forces. These general considerations are

summarized in Figure 1-4.[~17





CHEMISTRY


MOLECULAR


SYNTHESIS
Covelent
Bonds


SUPRAMOLECULAR


RECOGNITION


COMPLEXATION

Intermolecular
Bonds


TRANSPORT


Figure 1-4 From Molecular to Supra-
molecular Chemistry







9

The patterns of a supramolecular species have been named

molecular receptor and substrate. Molecular receptors are

organic structures, held by covalent bonds, which are able to

complex selectively ions or molecules. The substrates are not

limited to transition metal ions, but extending to all type

of substrates: cationic, anionic or neutral species of

organic, inorganic or biological nature. Substrate binding

makes use of various intermolecular interactions

(electrostatic interactions, hydrogen bonding, van der Waals

forces, short range repulsion, etc.) to form an assembly of

two or more molecules, a supermolecule.

For example, polynuclear aromatic hydrocarbons, such as

tetrakis(5,10,15,20-benzo-15-crown-5)porphyrin (TCP) and its

metal derivatives(MTCP), are well known to form supermolecular

systems.[1l] (Figure 1-5a)


/-\


/-"
0 O)
0 n


0 o o

) Chemical Structures of
(a) TCP & MTCP


(b) Schematic representation
of the K ion-induced dimers


Figure 1-5 An Example of a supermolecule







10
When TCP or MTCP is completed with cations, e.g. K+, Ba2+, and

NH4+, the dimeric porphyrins were formed.119 (Figure 1-5b) These

species are described as supermolecules since the two

porphyrin units joined by non-covalent interactions exhibited

optical absorption and emission properties different from

those of the monomeric porphyrin units.[20

In addition to binding sites, the receptor may bear

reactive sites or lipophilic groups for dissolution in a

membrane so that its functions include molecular recognition,

transformation and translocation. Using polymolecular

assemblies, structural organization and functional integra-

tion, chemical systems are built into supramolecular

architectures. That is called molecular and supramolecular

devices. The devices include five parts: supra-molecular

photochemistry and molecular photonics; molecular electronic

devices; molecular ionic devices; molecular self-assembling

and chemionics.

Molecular self-assembling is one of the molecular and

supramolecular devices. Such self-assembling has recently

been shown to occur in repetitive chain ligands, such as

poly(2,2'-bipyridine) which form the polynuclear complexes

with metal centers. The inorganic double helical structures

in these complexes have been confirmed.[2 This spontaneous

formation of an organized structure of intermolecular type

opens ways to the design and study of the self-assembling

phenomenon.







11

Molecular self-assembling is well documented in biology,

much less so in chemistry. "Inorganic double helical"

complexes have been studied in our group since 1970's. In

order to open a general way for generating inorganic double

helical structures, we extended pure poly(2,2'-bipyridine) to

special derivatives of pyridine, such as bis(2-acetylpyridine)

succinic acid dihydrazone, to design new inorganic double

helical complexes and to further understanding of self-

assembling, molecular devices and supermolecular structures.














CHAPTER TWO
REACTIONS OF CHLORAMINE WITH SOME METHYL PYRIDINES


Historical View

Numerous investigations have examined the use of

chloramine as an aminating agent for a variety of nucleophilic

substances, notably molecules containing nitrogen or

phosphorus donor atoms.122 However, little work on the

chloramination of nitrogen heterocyclic aromatic compounds has

been reported to date.

In view of the broad applicability of the chloramination

reaction with various nucleophiles, the unanswered question

concerning the reactions of chloramine with nitrogen

heterocycles merited further investigation. Of all the known

nitrogen heterocyclic systems, pyridine has perhaps the

greatest importance, whether judged by the variety and

interest of its derivatives and their reactions or simply by

the volume of literature devoted to them.

An early paper[1 contained a brief statement that in

attempts to chloraminate pyridine and 2-methylpyridine, the

only solid product isolated was ammonium chloride. In the

pyridine reaction there was evidence of decomposition of the

heterocyclic base. Shortly after the appearance of this

paper, a note by Brooks and Rudner241 reported that passage of






13

gaseous chloramine through liquid quinoline and liquid

pyridine gave low yields of 2-amino quinoline and 2-amino
pyridine respectively. (Figure 2-1)


+ NH2Cl (g)


+ HC1


NH2


+ NH 2 C (g)


+ HCI


Figure 2-1


The Products of Chloramine(g) Through
Quinoline and Pyridine


They also tentatively reported the formation of the 8-amino

derivatives of theobromine and caffeine (Figure 2-2) by
analogous reactions.


O ,CH3

H3C-N \


CH N
CH3


,CH3
,N

1>
*N


Caffeine Theobromine
( 1,3,7- trimethylxanthine ) (3,7- dimethylxanthine)

Figure 2-2 Caffeine and Theobromine







14

Various substituted N- aminopyridinium cations have been

reported as products of the reactions of heterocyclic nitrogen

bases with potassium sulfonyl hydroxylamine and hydroiodic

acid: H2N-OSOS'K+ HI, 261 or O-mesitylene-sulfonyl-

hydroxylamine.1]1 (Figure 2-3) However, no crystal structures

of substituted N-amino pyridinium cations have been reported.




CH3

NH2OSOS2 3CH


CH3

Figure 2-3 O-Mesitylene-Sulfonyihydroxylamine


In the present chapter, the reactions of chloramine with

2,3-, 2,4-, 2,6-, 3,5- dimethyl pyridine and 2,4,6,- trimethyl

pyridine were examined. In the case of 3,5-dimethyl pyridine

a solid amination product was isolated in high yield and its

structural formula was shown to be N-amino(3,5-dimethyl-

pyridinium) chloride (Figure 2-4) by an X-ray crystal

structural study. The only solids isolated in the other cases

were ammonium chloride and the respective pyridinium

chlorides. The results obtained have practical and

theoretical significance.











CIH3 CH3


N
I
NH2

Figure 2-4 N-amino(3,5-dimethylpyridinium) Chloride



Synthesis of Chloramine with Some Methylpyridine


Experimental Materials


The 2,3-, 2,4-, 2,6-, and 3,5-lutidine and 2,4,6-

collidine from the Aldrich Chemical Company were used as

obtained. Chloramine was prepared by the gas-phase reaction

of chlorine-nitrogen mixtures with gaseous ammonia in a

Sisler-Mattair type reactorIl (Figure 2-5). Solutions of

chloramine in ether were prepared by passing the effluent gas

from the reactor into anhydrous ether and pouring the

resulting solution through a column of anhydrous copper

sulfate to remove the ammonia.128


Experimental Method


The reactions with all the pyridine derivatives were

carried out at 0C by stirring the pyridine derivative with

an ether solution of a slight excess of chloramine. The

reaction with 2,6-lutidine is typical. One hundredth mole of

2,6-lutidine was mixed with 40 mL of 0.3M chloramine solution








16



















0

o z






U- '
I









04 o




Iw .
H s s


Li ( i
8o~. S
C, w 01s



C, W fl














W %^b 1t







17

in ether (0.012 mol NH2Cl, 20% excess), stirred for eight

hours at 0C, and allowed to stand overnight. The white

precipitate that formed was filtered off and shown to be

ammonium chloride (mp.> 3000C). The filtrate was evaporated

to a volume of 10 mL by passing dry nitrogen over it for a

period of 2 hours and then allowed to stand overnight in a

refrigerator. Yellow crystals formed but were shown by

melting point determination (218 2190C) and elemental

analysis to be the hydrochloride of 2,6-lutidine. An

authentic sample of the hydro-chloride of 2,6-lutidine was

prepared from 2,6-lutidine and dry HC1 and was used for

comparison to confirm this conclusion. No other solid product

was obtained.


Experimental Results


Analogous results were obtained in the reactions of

chloramine with 2,4- and 2,3-lutidines, and with 2,4,6-

collidine, the only solid products isolated being ammonium

chloride and the hydrochlorides of the respective nitrogen

bases. The analyses and melting points of the hydrochlorides

are listed in Table 2-1. Different results were obtained in

the reaction with 3,5-lutidine. In this case concentration

of the final filtrate resulted in the formation of pale yellow

crystals which after recrystallization from a 2:1 mixture of

acetone and chloroform melted at 227-2290C. Elementary

analysis:







18

Found for C7HllN2C1: C, 53.00%; H, 7.32%; N, 17.39%

Calcd. for C7HllN2C1: C, 53.00%; H, 6.99%; N, 17.66%



These data indicate the amination of the lutidine by

chloramine. The weight of this product corresponded to a

yield of 75.4% of theoretical.





TABLE 2-1

Melting Points and Elemental Analyses
of the Products of the Reactions with Chloramine



m.p.C %C %H %N


2,6-lutidine 218-219 58.95 7.03 9.68

2,4-lutidine 208-210 58.76 7.10 10.01

2,3-lutidine 202-204 59.01 7.05 9.93

Theory for [(CHs)2CH3NH]C1 58.53 7.03 9.76


2,4,6-collidine 230-231 58.30 7.67 8.71

Theory for [(CH3),CH2NH]Cl 60.95 7.67 8.88


3,5-lutidine 227-229 53.00 7.32 17.39

Theory for [(CHS)2,CH3NNH2]C1 53.00 6.99 17.66







19

Crystal Structure of N-amino(3.5-DimethvlDvridinium)


To establish unequivocally the identity of the above

amination product, the structure was determined by X-ray

diffraction. A well shaped crystal of 0.2 x 0.2 x 0.15 mm

size was used for intensity measurements on Nicolet P1 bar

diffractometer with Ni filtered-CuKa radiation. Reflections

were collected in the 20 range 1.5-112.00 using the 0-20 scan

mode and a variable scan speed (1.90-29.300 min-'). Two check

reflections measured after every 49 reflections showed an

intensity variation of 5%. Of 1193 reflections measured,

1004 with I>2.5a(I) were used in calculations. Pertinent data

are listed in Table 2-2.

The structure was solved by the heavy-atom method. The

difference maps showed positions of all H-atoms bonded to ring

and the NH2 group, and indicated CH3- groups having H-atoms in

two orientations (rotated by 600). Because not all methyl

hydrogen atoms gave suitable bond angles, coordinates of three

of them were calculated assuming tetrahedral geometry around

the carbon atoms. Non-hydrogen atoms were refined with

anisotropic thermal factors. The parameters of the H-atoms

were included in the structure factor calculations but they

were not refined. The isotropic temperature factor of 0.05

A2 was assigned to all H-atoms. The final refinement of all

parameters converged at R=0.069 and R,=0.037 where w=a-'. The

residual peaks in the final difference map were in the range







20

from -0.54 to 0.66 eA-3. All calculations were carried out

using the DESK TOP SHELXTL (Nicolet, 1986).12 Crystal data

are summarized in Table 2-2 through 2-7. The structure is

illustrated in Figure 2-6.

Discussion


The results of these experiments demonstrate conclusively

that chloramine in anhydrous ether solution free of ammonia

react with 3,5-lutidine to give the expected hydrazinium-type

salt in good yields by the amination of the ring nitrogen in

accordance with the following equation



3,5,-(CH3)2C5H3N + NHC1l [3,5-(CH3) CsH3NNH ]Cl



In the amination product the C1- ion is in the correct

relative position found in the crystal to show the N-H.....C1

hydrogen bond:


H(lla)......C1' 2.203(6)A N(la)-H(lla).....Cl' 172.9(4)0

H(12a).....C1 2.381(6)A N(la)-H(12a).....C1 170.7(4)0

Cl' at -x, l-y, 1-z


In contrast, 2,3-, 2,4-, and 2,6-dimethylpyridine and 2,4,6-

trimethylpyridine do not appear to undergo this reaction.

Instead, ammonium chloride and the hydrochlorides of the

respective nitrogen bases are the only products isolated.










TABLE 2-2

Crystal Data for [CyH1N2J]C1


[ C7HjN, ]Cl


Molecular Weight

Crystal System

Space Group

a, A

b, A

c, A

a, deg

P, deg

y, deg

Volume, A3

Z

d(calcd), g/cm3

Crystal Size, mm3

Radiation Used

I, cm-1

20 Range, deg

Number of collected data

Data with I>2.5aI

Goodness of Fit

R, %

R, %


158.64

Triclinic

P 1 Bar

7.663(1)

8.241(2)

8.266(2)

116.75(2)

115.39(2)

91.85(2)

404.4(20

2

1.30

0.2 x 0.2 x 0.15

CuKa

35.8

1.5 112.0

1193

1004

8.281

6.9

3.7


Formula










TABLE 2-3

Final Positional Parameter (x 104) and
Isotropic Thermal Parameters (AVxl03)
for N-amino-3,5-dimethylpyridinium chloride


ATOM X Y Z U*


Cl 1715(2) 2597(2) 4930(2) 56(1)

N(1) 3842(5) 7643(5) 6261(6) 41(2)

N(1A) 2052(6) 6360(6) 4455(6) 51(2)

C(2) 4237(7) 9471(7) 6744(7) 44(3)

C(3) 5974(7) 10762(7) 8443(7) 42(3)

C(3A) 6426(7) 12801(7) 8995(8) 53(3)

C(4) 7350(7) 10166(6) 9672(7) 43(3)

C(5) 6937(6) 8295(6) 9156(7) 39(3)

C(5A) 8410(7) 7619(7) 10473(8) 53(3)

C(6) 5174(7) 7055(6) 7439(7) 41(3)


* Equivalent isotropic U defined
of the orthogonalised Ui tensor


as one third of the trace











TABLE 2-4

Selected Distances (A) and Angles (o)
for N-amino-3,5-dimethylpyridinium


Bond Distances (A)


N(1)-N(1A)

N(1)-C(6)

C(3)-C(3A)

C(4)-C(5)

C(5)-C(6)


1.399(4)

1.352(7)

1.513(8)

1.386(8)

1.358(5)


N(1)-C(2)

C(2)-C(3)

C(3)-C(4)

C(5)-C(5A)


1.359(7)

1.355(5)

1.396(8)

1.518(8)


Bond Angles (0)


N(1A)-N(1)-C(2)

C(2)-N(1)-C(6)

C(2)-C(3)-C(3A)

C(3A)-C(3)-C(4)

C(4)-C(5)-C(5A)

C(5A)-C(5)-C(6)


118.1(4)

121.2(2)

121.0(5)

120.5(3)

121.3(3)

119.9(5)


N(1A)-N(1)-C(6)

N(1)-C(2)-C(3)

C(2)-C(3)-C(4)

C(3)-C(4)-C(5)

C(4)-C(5)-C(6)

N(1)-C(6)-C(5)


120.6(4)

120.6(5)

118.5(5)

120.4(3)

118.9(5)

120.5(5)


~=I~~~~~======E==C======~=~============~










TABLE 2-5
Anisotropic Thermal Parameters (A2x03)
for N-amino-3,5-dimethylpyridinium chloride


U11 U22 U33 U23 U,1 U12

Cl 45(1) 53(1) 54(1) 31(1) 10(1) 5(1)

N(1) 35(2) 46(2) 39(2) 24(2) 15(2) 7(2)

N(1A) 39(2) 53(2) 45(2) 24(2) 9(2) 0(2)

C(2) 40(3) 51(3) 44(3) 31(3) 17(2) 15(2)

C(3) 38(3) 47(3) 49(3) 31(3) 20(2) 11(2)

C(3A) 52(3) 45(3) 62(3) 32(3) 22(3) 13(2)

C(4) 37(3) 46(3) 44(3) 25(2) 16(2) 7(2)

C(5) 36(3) 42(3) 43(3) 27(2) 18(2) 11(2)

C(5A) 43(3) 50(3) 54(3) 33(3) 9(3) 7(2)

C(6) 39(3) 44(3) 45(3) 27(2) 20(2) 11(2)



The anisotropic temperature factor exponent takes the form:

-2" (h2a *2Ul+k2b U*U2+lc *2U3+2klb* cU23+2hla* c U+2hka*b*U,,)











TABLE 2-6

H-Atom Coordinates (x 10') and
Isotropic Thermal Parameters (AxlO0)
for N-amino-3,5-dimethylpyridinium chloride


ATOM X Y Z U


H(51A) 9580 8668 11614 50

H(52A) 8819 6647 9635 50

H(53A) 7793 7135 11015 50

H(51B) 7874 6151 9524 50

H(52B) 8678 8425 12236 50

H(53B) 9938 8096 10972 50

H(11A) 883 6789 4643 50

H(12A) 1830 5219 4429 50

H(2) 3232 9844 6028 50

H(31A) 4947 12721 7985 50

H(32A) 7472 12861 8526 50

H(33A) 6741 13659 10441 50

H(31B) 7851 13563 10159 50

H(32B) 5394 13411 9264 50

H(33B) 6424 12685 7973 50

H(4) 8691 11182 11030 50

H(6) 4641 5574 6828 50











TABLE 2-7

Distances (A) and Angles (0) Involving the H Atoms
for N-amino-3,5-dimethylpyridinium Chloride


Bond Distances (A)


N(la)-H(lla)
C(2)-H(2)
C(3a)-H(31a)
C(3a)-H(32a)
C(3a)-H(33a)
C(5a)-H(51a)
C(5a)-H(52a)
C(5a)-H(53a)
C(4)-H(4)


1.021(5)
0.909(5)
1.058(5)
1.038(7)
0.983(6)
0.965(4)
0.961(6)
0.955(8)
1.061(3)


N(la)-H(12a)
C(6)-H(6)
C(3a)-H(31b)
C(3a)-H(32b)
C(3a)-H(33b)
C(5a)-H(51b)
C(5a)-H(52b)
C(5a)-H(53b)


0.939(5)
1.072(5)
1.011(4)
1.002(6)
0.806(8)
1.041(5)
1.212(6)
1.051(6)


Bond Angles (0)


N(1)-N(la)-H(lla)
H(lla)-N(la)-H(12a)
C(3)-C(2)-H(2)
C(3)-C(3a)-H(32a)
C(3)-C(3a)-H(33a)
H(32a)-C(3a)-H(33a)
C(3)-C(3a)-H(32b)
C(3)-C(3a)-H(33b)
H(32b)-C(3a)-H(33b)
C(5)-C(4)-H(4)
C(5)-C(5a)-H(52a)
C(5)-C(5A)-H(53A)
H(52a)-C(5a)-H(53a)
C(5)-C(5a)-H(52b)
C(5)-C(5a)-H(53b)
H(52b)-C(5a)-H(52b)
C(5)-C(6)-H(6)


107.8(4)
98.2(5)
120.5(5)
101.9(5)
110.5(7)
121.1(4)
111.7(6)
101.3(5)
113.5(7)
120.9(5)
109.5(5)
109.9(5)
109.8(6)
111.2(4)
116.9(6)
93.4(3)
128.0(5)


N(1)-N(la)-H(12a)
N(1)-C(2)-H(2)
C(3)-C(3a)-H(31a)
H(31a)-C(3a)-H(32a)
H(31a)-C(3a)-H(33a)
C(3)-C(3a)-H(31b)
H(31b)-C(3a)-H(32b)
H(31b)-C(3a)-H(33b)
C(3)-C(4)-H(4)
C(5)-C(5a)-H(51a)
H(51a)-C(5a)-H(52a)
H(51a)-C(5a)-H(53a)
C(5)-C(5a)-H(51b)
H(51b)-C(5a)-H(52b)
H(51b)-C(5a)-H(53b)
N(1)-C(6)-H(6)


110.0(4)
118.2(4)
96.1(4)
115.8(7)
108.1(6)
112.8(5)
112.9(4)
103.8(7)
118.7(5)
109.1(5)
109.0(6)
109.5(6)
103.2(3)
121.6(7)
111.4(5)
111.6(3)


=~===~=~======~~~~=e==~~~~~=============


































-,.
r3
UU









) z
4-)






oe




qs
r0)















4t

*4
^1







-g



fn






28












Z3







0




t-
C)




~v~t I~ I







29

Since in each of these bases there are one or two methyl

groups alpha to the ring nitrogen, the attribution of these

results to spatial interference of the alpha methyl group is

a reasonable hypothesis. However, the presence of methyl

groups in the 2-position of the ring should increase the

electron density on the ring nitrogen and thus favor the

amination of the nitrogen by chloramine. The hypothesis of

spatial interference is, of course, speculative.

On the other hand, various substituted N-aminopyridinium

cations have been reported as products of the reactions of

pyridine and its alpha methyl derivatives with large counter

ions, such as iodide or mesithylenesulfonate ions. This

indicates that the further research including an examination

of solubilities or lattice stabilization of potential products

is necessary to obtain a satisfactory explanation.

There are two interesting features of the structure of

N-amino-3,5-dimethylpyridinium ion: the N(1)-N(1A) distance

and the change in the dimensions of the ring relative to other

pyridine derivatives.

The N(1)-N(1A) distance of 1.399(4) A in N-amino-3,5-

dimethylpyridinium is shorter than the N-N distances observed

in 2,2-dimethyltriazanium chloride (N(1)-N(2) 1.439(6) A and

N(1)-N(3) 1.462(6) A) (Figure 2-7a) and in 1,1,1-trimethyl

hydrazinium chloride (N(1)-N(2)=1.463(3) A)(Figure 2-7b).[0







30
Effect of atom hybridization on bond lengths has been

described in many articles and books. H.A.Bent described this

effect in detail.3l1 He illustrated the effect of atom

hybridization on bond lengths of carbon-carbon bonds in the

following data. (Table 2-8)


W- -


1.439(6) 1.462(6)
N(2) 1) N(3)


1"I


6L7~.


Figure 2-7 2,2-Dimethyltriazanium (a) and
1,1,1-Trimethylhydrazinium Chloride



TABLE 2-8
The Effect of Atom Hybridization on
Bond Lengths of C-C Bond


Type of Bond Bond Length(A) Type of Bond Bond of Length(A)

sp3-sp3 1.54 sp3-sp2 1.50

spS-sp 1.46 sp2-sp2 1.46

sp-sp 1.42 sp-sp 1.38
sp -sp2 +r 1.34 spS-sp +r 1.31

sp-sp +7 1.28 sp-sp +2r 1.20


- .463 34
N(2) N


f
[1)~-------







31

The useful rules which were indicated in these data are

that: (1) The carbon-carbon single bond distance decreases

by 0.04 A when one of the participating carbon atoms changes

hybridization type from sp3 to sp', or from sp2 to sp. (2)

When a r bond exists superimposed on the a bond, the figure

0.03 A is a better one to use.

Burke-Laing and co-workers discussed the relationship

between the bond lengths and bond orders in their paper.[n]

According to the paper single bond between two sp2 N atoms

has been estimated to be 1.41 A. On this basis the sp3 N-N

single bond would be 1.47-1.49A, which is close to the value

of 1.50 A,I31 a consequence of the sp3 hybridization of N which

is expected to increase the N radius (sp2) by about 0.04 A.

Thus the shorter N-N distance in N-amino(3,5-dimethyl-

pyridinium) ion would indicate that the N(1)-N(1A) bond has

some double bond character. However, as can be seen in the

Figure 2-6, the two H atoms bonded to N(1A) are not coplanar

with the pyridine ring as might be expected. Therefore, the

N-N bond may be considered to be an essentially single bond

with possibly some shortening resulting from formal charge.

The second interesting feature is that the formation of

the N-amino(3,5-dimethylpyridinium) ion results in significant

changes in the dimensions of the pyridine ring. Pyridine in

the gas phase has equal C-C bond length of 1.392(1) A, the

C-N bond lengths are 1.340(1) A and the C-N-C angle is

116050'.1341







32

Unfortunately, the crystal structure of pyridine has not been

reported yet. We searched these compounds which contained

simple pyridine rings (such as pyridine hydrogen fluoride) to

survey the parameters of pyridine in solid phase. The average

parameters of the 16 compounds (APPENDIX A) in 1987-1989

release in CSD are as follows:

C-C 1.375 A C-N 1.337 A C-N-C 117.130.

It indicates the parameters of pyridine in solid phase are

almost the same as those in gas phase. In the N-amino(3,5-

dimethyl-pyridinium) ion the C-N-C angle is increased to

121.3(4)0 and the C-N distances increase to 1.357(8) A.

An increase in the C-N-C angle in the pyridine ring

occurs on either substitution, coordination to a metal ion,

or pyridinium ion formation. The Figure 2-8 showed the

increase of the C-N-C angle in pyridine rings. The change in

the bond angle may be rationalized in terms of an assumption

of increased s-character in the C-N bond as predicted by

Bent's rules.131 For a familiar example, from the bond angle

in NH3 (106046') compared to that in H20 (104027') it is

inferred that nitrogen atom of NH, devoted slightly more s

character to its bonding orbitals than the oxygen atom of H20.

However, the change in the bond lengths of the pyridine

ring on either substitution, I361 ]] coordination to a metal

ion,371 or pyridinium ion18'1391 formation appears to be more

subtle and to depend on the nature of the group bonded to the

nitrogen lone pair. Some examples are illustrated below.



























Q)







0)
*o




4 c4



I0
1!0

o
0





r4
OC
*H



co
O








4 t
*rq
F)











Q)
0'
c







F __________ _________________


r---
CM

(0
CN


80
.,--
(11





;O
C\1




C)
()H
CO















: N-

(9-VIPIODSDI1iND ]Hi 4*ON






35
Example 1 z The Structure of Dipyridinum oxalate-oxalic

acid401 (Figure 2-9)
The structure consists of two pyridinium ions hydrogen
bonded to one oxalate ion, which lies on a center of symmetry.
An additional centrosymmetric oxalate acid molecule forms
hydrogen bonds with the oxalate moiety to give linear chains
along the C-axis. The bond distances (A) within the pyridi-






C6 O







004
C50c 0-cl






04

O
03'


Figure 2-9 Dipyridinium Oxalate-Oxalic acid
( one pyridinium is omitted)


nium cation and the angle (C-N-C) are as follows:

N-C(3) 1.312(2) N-C(7) 1.331(2)
C(3)-C(4) 1.366(2) C(4)-C(5) 1.370(2)
C(5)-C(6) 1.357(2) C(6)-C(7) 1.356(2)

C(3)-N-C(7) 122.1(2).







36

Bond distances within the pyridinium cation are short by

comparison to expected aromatic C-C (1.392 A) and C-N (1.340

A) distances. Such shortening is generally observed in

crystal structures containing pyridinium ions. However, most

suffer from disorder or high thermal motion and exhibit

shortened bond distances. Taking account of that error yields

average C-C (1.37 A) and C-N (1.31 A) distances that are close

to the values for this compound.

Example 2 : l,l'-methylene-bis(4,4'-dimethylamino

pyridinium) ion [C1rH22N4]2+ 11 (Figure 2-10)



0 c c 3
C1
-'O--cN1 C4 -N2

c ---

Figure 2-10 1,1'-methylene-bis(4,4'-dimethyl-
aminopyridinium) ion




The bond distances (A) within the pyridinium cation and

the angle (C-N-C) are as follows:


C(2)-N

C(2)-C(3)

C(3)-C(4)

C(2)-N-C(6)


1.345

1.351

1.419

119.50.


C(6)-N

C(5)-C(6)

C(4)-C(5)


1.350

1.351

1.417






37
The distances of C(2)-N, C(6)-N and C(3)-C(4), C(4)-C(5) are
longer and ones of C(2)-C(3), C(5)-C(6) are shorter in compa-
rison with the distances of C-N (1.340 A) and C-C (1.392 A)
in gaseous pyridine.
The resonance structures (A & B) (Figure 2-11) were
proposed to explain the differences between pyridine and the
ion. The positive charge presented on the N atoms is not
localized as implied by the structure (A). Instead the
positive charge is completely delocalized throughout the
molecule. In the other words, the exocyclic nitrogens share
the positive charges through the synergistic interaction as


CH3N NCH3 CH3+ /CH3


+N


+N
I I




I II


CH CH3 CH CH3
A B
Figure 2-11 The Resonance Structure of [CiH22N4] 2+







38

shown by the structure (B). The structure, therefore, does

make a significant contribution to the overall structure.

This is consisted with the enhanced resonance effects

associated with r-electron donors and their stabilizing

interactions. The geometry optimized INDO calculations have

shown that the quinoid resonance hybrids (B) do make a

definite contribution to the overall structure of the species.

This resonance structure (B) readily account for the changes

of these distances.

Although there are the very similar changes in N-

amino(3,5-dimethylpyridinium) chloride. The related distances

(A) are:



C(2)-N(1) 1.359 C(6)-N(1) 1.352 (longer)

C(2)-C(3) 1.355 C(5)-C(6) 1.358 (shorter)

C(3)-C(4) 1.396 C(4)-C(5) 1.386 (longer).



The explanation of the resonance structures is not reasonable.

Because if it were true, the resonance structures would be C

and D. (Figure 2-12) The structure (D) is unfavorable.

Unfortunately, there are no other compounds which are

strictly analogous for a comparison. However, these changes

in the compound may account for the observed reactivity of

pyridinium ions and related species.













C HI H



CH31 C3


H. + H


CH3


'CH3


D


Figure 2-12 Impossible Resonance Structures
for [C7H1N2]+


In the future, our group will try to obtain analogous
compounds for a comparison with the N-amino (3,5-dimethyl-
pyridinium) ion. We will also utilize the Cambridge
Structural Database to analyze the structural data for
pyridine rings to understand the changes in these compounds.














CHAPTER THREE
METAL COMPLEXES WITH NONPLANAR MULTIDENTATE LIGANDS


Quadridentate Ligand


The nonplanar multidentate ligands are chosen to synthe-

size metal complexes with "helical" coordination. Helical

coordination compounds will be discussed in more detail in the

next chapter. The simplest nonplanar multidentate ligand is

the quadridentate group. The following patterns are possible

for the arrangement of donor atoms in quadridentate

ligands141 (Figure 3-1). Most of the known quadridentate

chelating ligands have the linear arrangement of donor atoms

depicted by pattern [4-1]. These linear ligands can be

further subdivided into three stereochemical types: (a)

Planar ligands are those which are constrained to coordinate

with a metal ion in such a way that donor atoms lie in a

plane. (b) Nonplanar ligands are constructed so that the

donor atoms cannot lie in a plane, but may be arranged

tetrahedrally about a metal ion. (c) Facultative ligands are

flexible so that the donor atoms can be coordinate from either

a planar or nonplanar arrangement.

The metal atoms with coordination number four may require

a tetrahedral or a square planar arrangement of their coordi-












4-1 4-2 4-3 4-4





4-5 4-6 4-7






4-8 4-9 4-10 4-11


Figure 3-1 Possible Patterns for Quadridentate
Chelating Agents



nation covalences. Consequently, the quadridentate ligand

must be spatially capable of presenting its four donor atoms

to the metal atom from the apices of either a circumscribing

tetrahedron or a square.

Six covalent metal atoms which have an octahedral

disposition of covalences can also combine with quadri-

dentates. To a six coordinate metal atom a quadridentate

residue must be capable of presenting its four donor atoms

spatially in one of two ways. Either all four donors lie in

a plane leaving two vacant apices in the trans positions or

alternatively the two apices of the coordination octahedron

not occupied by the quadridentate are in cis positions to each

other.







42

Ligands of pattern [4-1] can be designed in such a way

that they can not be planar, but fix strainlessly into a

tetrahedral arrangement. The phenomenon of restricted

rotation in the hindered biphenyl compounds has been used to

synthesize nonplanar quadridentate chelating agents. Lions

and co-workers141 designed the quadridentate chelate ligands

with a molecule capable of presenting four donor atoms to a

metal atom from the apices of a circumscribing tetrahedron.

(Figure 3-2)


2,2'-bis-(2"-phenolmethyleneamino) -
6,6'-dimethylbiphenyl


2,2'-bis-(8"-quinolylmethylene-
amino)-biphenyl


Figure 3-2 The Examples of Nonplanar Quadridentate
Chelating Agents


The description of stereochemical configuration has been

used to design the specific quadridentate ligand and to

synthesis some metal complexes.







43

Ligand

Stereochemical Feature


In addition to the factors affecting the stability of

metal complexes, various considerations of geometry must be

borne in mind when designing a multidentate ligand. Various

stereochemical features influence the shape and flexibility

of organic compounds in general. Conformational preferences

can also affect the particular shape of a molecule. When

these stereochemical features occur in ligands they may

influence the geometrical arrangement of donor atoms in a

derived metal complex or the precise configuration of such a

complex.

According to these normal stereochemical effects of

organic molecules, it seems to me that a quadridentate ligand

of a Schiff base which contains biphenyl ring is a useful

linear multidentate ligand to synthesize metal complexes and

to study "helical" coordination compounds.

The particular advantage of the basic salicylaldimine

ligand system has been the considerable flexibility of the

synthetic procedure which has allowed the preparation of a

wide variety of complexes with a given metal whose properties

are often strongly dependent on the detailed ligand structure.

The 2,2'-diaminobiphenyl was selected as the primary

amine and reacted with salicylaldehyde to form salicylaldimine





44
ligand. The reason is that biphenyl is one of the simplest
molecules which may yield a helical conformation.
The structural information indicating the helical
conformation is available for many molecules.MI Some
examples are illustrated in Figure 3-3, such as biphenyl,
tris-chelates and two or three arylgroups are attached to a
central atom.


O
II
C
(Or UO


I o
O\i


Figure 3-3 Some Molecules with a Helical
Conformation


co- 0


O
At'0
6(~BI*0







45

The 2,2'-bis(salicylideneamino)biphenyl ligand system

potentially has three important structural consequences: []

(i) disposing itself in a nearly strainless manner to form an

OgN2 tetrahedron; (ii) forming complexes resistent to

racemization of the absolute configuration (A, A) at the metal

due to the high activation energy ( 45 Kcal/mole ) for parent

diamine; (iii) producing tetrahedral complexes of known

absolute configuration because the chirality of the complex

is necessarily that of the diamine. In the present chapter,

detailed discussion is confined to 2,2'-bis(salicylideneamino)

biphenyl ligand and its complexes.


Synthesis of the Ligand


Synthesis of 2.2'-diaminobiphenyl


Finely powdered 2,2'-dinitrobiphenyl (20g) was heated on

a water-bath with tin (100g) and concentrated hydrochloric

acid (200mL) until a clear solution was obtained. The

solution was treated with excess of caustic soda and extracted

with ether. The diaminobiphenyl was recovered and separated

from ligroin (b.p. 60-80 OC) as light yellow crystals. The

products were recrystallized from cyclohexane, forming

colorless crystals. The weight of this product corresponded

to a yield of 78% of theoretical. The melting point of the

products is 81 OC. The elementary analysis showed:











Found:

Calculated:


C %

78.31

78.25


H %

6.61

6.55


N %

15.22

15.20.


Synthesis of 2.2'-bis-(salicylideneamino)biphenyl (sal)bp


The 2,2'-diamino-biphenyl (0.55g, 3.0 x 10-3 mol) was

mixed with 50mL ethanol at 400C, stirred for about 30 minutes

until 2,2'-diaminobiphenyl was dissolved completely. Salicyl-

aldehyde (0.73g, 6.0 x 10-S mol) was added to the ethanol

solution, stirred for 2 hours at 400C. The bright yellow

precipitate that formed was filtered off and shown to be 2,2'-

bis (salicylideneamino) biphenyl (sal),bp. (Figure 3-4)


Figure 3-4 2,2'-bis-(Salicylideneamino)biphenyl
(sal)2bp







47

The weight of this product corresponded to a yield of 98%

of theoretical. The melting point of the products was 1520C.

The elementary analysis showed:


C % H% N%

Found: 79.42 5.10 7.01

Calculated: 79.57 5.14 7.14.


The filtrate was evaporated slowly at room temperature. Well

shaped yellow crystals formed in the filtrate. One of these

was used for X-ray studies.


Crystal Structure


To establish unequivocally the geometry of the above

condensation product, the structure was determined by X-ray

diffraction. A well shaped crystal of 0.27 x 0.10 x 0.034 mm

size was used for intensity measurements on Nicolet P1 bar

diffractometer with Ni filtered-CuKa radiation. Reflections

were collected in the 20 range 1.5-112.50 using the 0-20 scan

mode and a variable scan speed (1.90-29.300 min-1). Two check

reflections measured after every 48 reflections showed an

intensity variation of 5%. Of 2934 reflections measured,

1989 with I2.0o(I) were used in calculations. Pertinent data

are listed in Table 3-1.

The structure was solved by the direct method (SOLV).

The position of all H-atoms was shown in the difference maps.







48

Non-hydrogen atoms were refined with anisotropic thermal

factors. The parameters of the H-atoms were included in the

structure factor calculations but they were not refined. The

isotropic temperature factor of 0.07 A2 was assigned to all H-

atoms. The final refinement of all parameters converged at

R=0.081 and R,=0.049 where w=a-2. The residual peaks in the

final difference map were in the rang from -0.33 to 0.23 eA3.

All calculations were carried out using the DESK TOP SHELXTL

(Nicolet, 1986). Crystal data are summarized in Table 3-1

through 3-6. The structure is illustrated in Figure 3-5.


Metal Complexes

The following metal ions ( Fe3+, Co2+, Ni+, Cu2+, Zn+,

Hg Ce Bi+ and Pb+ ) were reacted with the ligand

(sal)2bp. Only Cu2+ and Fe3+ formed crystals which were

suitable for X-ray studies.


Copper(II) Complex


Synthesis of copper-complex


The 2,2'-bis(salicylideneamino)biphenyl (0.392g, 1.0 x

10-3 mol) in 50 mL methanol at about 400C was stirred until the

ligand was dissolved completely. Sodium methoxide (0.108g, 2.0

x 10-3 mol) in 20 mL methanol was added to the methanol

solution and stirred for about 1 hour. Copper nitrate(0.221g,

1.0 x 10-Smol) was added to the methanol solution, forming a

deep green solution. The green solution was refluxed for

about 4 hours, cooled and filtered. Slow evaporation of the







49

TABLE 3-1

Crystal Data for [C26H2,NfO2)


[(C26H2,N2O2


Molecular Weight

Crystal System

Space Group

a, A

b, A

c, A

a, deg

f, deg

1, deg

Volume, A3

Z

d(calcd), g/cms

Crystal Size, nmm

Radiation Used

#, cm-'

29 Range, deg

Number of collected data

Data with I2.0oI

Goodness of Fit

R, %

R, %


392.5

Triclinic

P 1 bar

10.127(2)

10.811(2)

11.409(3)

116.93(2)

101.03(2)

102.58(2)

1024.7(40

2

1.27

0.27 x 0.10 x 0.034

CuKa

6.09

1.5-112.5

2934

1989

2.437

8.1

4.9


Formula











TABLE 3-2

Final Positional Parameter (x 104) and
Isotropic Thermal Parameters (AVxl03)
for 2,2'-bis(salicylideneamino)biphenyl


ATOM X Y Z U*


C(1) 7284(4)
C(2) 8567(4)
C(3) 9615(4)
C(4) 9389(5)
C(5) 8137(5)
C(6) 7096(5)
C(1') 6140(5)
C(2') 5294(5)
C(3') 4240(4)
C(4') 3928(5)
C(5') 4724(5)
C(6') 5827(5)
C(7) 9599(4)
C(8) 9885(4)
C(9) 9355(4)
C(10) 9659(5)
C(11) 10523(5)
C(12) 11067(5)
C(13) 10758(5)
C(7') 4633(4)
C(8') 4933(5)
C(9') 6278(5)
C(10') 6506(5)
C(11') 5368(6)
C(12') 4045(6)
C(13') 3783(5)
N(1) 8779(3)
N(1') 5634(3)
0(1) 8479(3)
0(1') 7409(3)


980(4)
1899(4)
2946(5)
3056(4)
2151(5)
1117(5)
-177(5)
166(4)
-953(5)
-2422(4)
-2810(5)
-1677(5)
2659(4)
2333(5)
910(5)
641(5)
1803(5)
3222(5)
3481(5)
2122(5)
3652(5)
4716(5)
6176(5)
6530(5)
5483(7)
4027(6)
1616(4)
1692(3)
-262(3)
4380(3)


7345(4)
8480(4)
8432(5)
7283(5)
6108(4)
6167(4)
7328(4)
8189(4)
8101(4)
7107(5)
6229(5)
6362(4)
10839(4)
11943(4)
11712(4)
12785(5)
14120(4)
14373(4)
13306(4)
9618(4)
10690(4)
11270(5)
12255(5)
12630(4)
12082(6)
11088(5)
9581(3)
9201(3)
10415(3)
10919(3)


* Equivalent isotropic U defined
of the orthogonalised Uij tensor


as one third of the trace


50(3)
53(3)
59(3)
64(3)
65(3)
60(3)
55(3)
54(3)
58(3)
74(3)
76(3)
70(3)
57(3)
60(3)
59(3)
73(3)
81(3)
92(3)
79(3)
61(3)
58(3)
67(3)
79(3)
89(3)
104(4)
82(4)
56(2)
54(2)
68(2)
87(2)











TABLE 3-3

Bond Distances (A)
for 2,2'-bis(salicylideneamino)biphenyl


Bond Distances (A)


C(1)-C(2)

C(2)-C(3)

C(3)-C(4)

C(4)-C(5)

C(5)-C(6)

C(1)-C(6)

C(2)-N(1)

C(7)-N(1)

C(7)-C(8)

C(8)-C(9)

C(9)-C(10)

C(10)-C(11)

C(11)-C(12)

C(12)-C(13)

C(8)-C(13)

C(9)-0(1)

C(1)-C(1')


1.407(5)

1.402(7)

1.384(8)

1.392(5)

1.395(8)

1.400(8)

1.412(7)

1.300(4)

1.450(8)

1.394(8)

1.377(8)

1.394(5)

1.382(8)

1.363(9)

1.410(5)

1.372(4)

1.499(7)


C(1')-C(2')

C(2')-C(3')

C(3')-C(4')

C(4')-C(5')

C(5')-C(6')

C(1')-C(6')

C(2')-N(1')

C(7')-N(1')

C(7')-C(8')

C(8')-C(9')

C(9')-C(10')

C(10')-C(11,)

C(11')-C(12')

C(12')-C(13')

C(8')-C(13')

C(9')-0(1')


1.402(7)

1.399(7)

1.393(6)

1.379(8)

1.394(7)

1.403(6)

1.431(5)

1.288(6)

1.460(6)

1.378(7)

1.394(6)

1.375(8)

1.358(7)

1.386(7)

1.403(8)

1.352(7)









TABLE 3-4

Bond Angles (0) and Hydrogen Bonds
for 2,2'-bis(salicylideneamino)biphenyl


Bond Angles (0)


C(2)-C(1)-C(6)
C(6)-C(1)-(1,)
C(1)-C(2)-N(1)
C(2)-C(3)-C(4)
C(4)-C(5)-C(6)
C(1)-C(1')-C(2')
C(2 ')-C(1')-C(6')
C (1')-C(2')-N(1')
C(2')-C(3')-C(4')
C(4 )-C(5')-C(6')
C(8)-C(7)-N(1)
C(7)-C(8)-C(13)
C(8)-C(9)-C(10)
C(10)-C(9)-0(1)
C(10)-C(11)-C(12)
C(8)-C(13)-C(12)
C(7')-C(8')-C(9')
C(9 ') -C(8 ')-C(13')
C(8') -C(9') -0(1')
C(9')-C(10')-C(11')
C(11' )-C(12')-C(13')
C(2)-N(1)-C(7)


118.6(4)
118.9(3)
116.6(4)
119.5(3)
118.7(5)
123.0(4)
117.4(4)
117.5(4)
119.1(5)
117.8(4)
120.2(4)
119.5(5)
121.0(3)
117.8(4)
120.4(5)
121.5(5)
122.1(5)
120.3(4)
121.5(4)
118.8(4)
121.1(6)
120.7(4)


C(2)-C(1)-C(1 ')
C(1)-C(2)-C(3)
C(3)-C(2)-N(1)
C(3)-C(4)-C(5)
C(1)-C(6)-C(5)
C(1)-C(1')-C(6')
C(1')-C(2')-C(3')
C(3')-C(2')-N(1')
C(3' )-C(4')-C(5')
C(1')-C(6')-C(5')
C(7)-C(8)-C(9)
C(9)-C(8)-C(13)
C(8)-C(9) -0(1)
C(9)-C(10) -C(11)
C(11)-C(12)-C(13)
C(8' )-C(7' ) -N (1')


122.5(5)
120.3(5)
122.8(3)
121.5(5)
121.5(3)
119.6(4)
120.9(4)
121.5(4)
121.9(4)
122.8(5)
122.7(3)
117.8(5)
121.1(5)
119.6(5)
119.6(4)
121.2(4)


C(7')-C(8')-C(13') 117.5(4)
C(8')-C(9')-C(10') 120.2(5)
C(10')-C(9')-0(1') 118.2(4)
C(10')-C(11')-C(12')121.3(5)
C(8')-C(13')-C(12') 118.2(5)
C(2')-N(1')-C(7') 118.9(3)


Hydrogen Bonds
-------------------------------------------------------------------


O(1)-H(1) ......N(1)
0(1)-H(1) 1.117 A
0(1)-N(1) 2.591 A
0(1)-H(1)-N(1) 141.60
N(1) at X, Y, Z


0(1')H(1') ......N(1')
0(1')-H(1') 1.159 A
0(1')-N(1') 2.596 A
O(1')-H(1')-N(1') 141.30
N(1') at X, Y, Z











TABLE 3-5

Anisotropic Thermal Parameters (A2xl0S)
for 2,2'-bis(salicylideneamino)biphenyl


Ul U22 U U U2 U13 U12


47(3)
51(3)
46(3)
74(4)
63(3)
55(3)
55(3)
58(3)
55(3)
71(4)
79(4)
73(4)
64(3)
56(3)
57(3)
77(4)
74(4)
110(5)
91(4)
53(3)
67(4)
74(4)
96(4)
146(5)
133(5)
86(4)
56(3)
52(2)
64(2)
58(2)


51(3)
57(3)
55(3)
60(3)
73(4)
66(3)
56(3)
51(3)
52(3)
59(3)
57(3)
62(3)
55(3)
59(3)
70(3)
86(4)
109(4)
82(4)
67(3)
69(3)
60(3)
63(3)
56(3)
70(4)
120(5)
82(4)
57(2)
49(2)
54(2)
56(2)


51(3)
49(3)
66(3)
66(3)
62(3)
51(3)
51(3)
47(3)
63(3)
80(4)
76(4)
54(3)
56(3)
52(3)
54(3)
84(4)
63(3)
50(3)
63(3)
71(3)
53(3)
55(3)
57(3)
48(3)
116(5)
98(4)
51(2)
56(2)
68(2)
105(3)


20(2)
20(2)
25(3)
35(3)
32(3)
23(3)
26(3)
20(2)
32(3)
37(3)
26(3)
12(3)
29(3)
18(3)
30(3)
56(3)
43(3)
20(3)
27(3)
37(3)
28(3)
22(3)
13(3)
20(3)
68(4)
44(3)
24(2)
24(2)
24(2)
12(2)


23(2)
19(2)
21(3)
32(3)
26(3)
19(3)
18(3)
15(3)
19(3)
17(3)
27(3)
24(3)
22(3)
17(3)
27(3)
40(3)
23(3)
9(3)
13(3)
33(3)
27(3)
15(3)
8(3)
32(3)
81(4)
58(4)
16(2)
21(2)
29(2)
19(2)


21(5)
28(2)
10(3)
27(3)
29(3)
21(3)
19(3)
20(3)
8(2)
8(3)
13(3)
27(3)
26(3)
22(3)
26(3)
37(3)
39(3)
19(3)
25(3)
27(3)
29(3)
34(3)
27(3)
59(4)
93(4)
48(3)
23(2)
16(2)
2(2)
18(2)


The anisotropic temperature factor exponent takes the form:

-2r2 (h a *2U+k b U22+12 c US+2klb*c*U2+2hla c*Uis+2hka*b*UI2)


C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(1')
C(2')
C(3')
C(4')
C(5')
C(6')
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(7')
C(8')
C(9')
C(12')
C(11')
C(12')
C(13')
N(1)
N(1')
0(1)
0(1'










TABLE 3-6

H-Atom Coordinates (x 10') and
Isotropic Thermal Parameters (AxlO0)
for 2,2'-bis(salicylideneamino)biphenyl


ATOM X Y Z U


H(3)

H(4)

H(5)

H(6)

H(1)

H(7)

H(10)

H(11)

H(12)

H(13)

H(3')

H(4')

H(5')

H(6')

H(1')

H(7')

H(10')

H(11')

H(12')

H(13')


10698

9940

7807

5988

9079

9983

9419

10789

11644

11040

3529

3116

4485

6379

6972

3314

7611

5638

3207

2356


3745

4110

2215

303

604

3877

-277

1512

4038

4476

-758

-3190

-4175

-2087

3184

1393

7144

7804

5746

2842


9340

7201

5070

5197

10158

10907

12782

15058

15467

13379

8899

7048

5431

5691

9966

9226

12738

13361

12212

10302
























U,


010
00




L4J
w-a

r-4





c4J
0 9O



H H






4
0
l/3






04




4:
c,




















P 0)



r*H
ri-4







56




















b






0
o
O




, 0I.







57

green filtrate produced a deep green precipitate. The solid

was washed with water, and filtered, giving a deep green

powder. The weight of this product corresponded to a yield

of 46% of theoretical. The elementary analysis showed:


C % H % N %

Found: 68.96 4.12 6.13

Calculated: 68.78 4.00 6.17.


The products were recrystallized from methanol, producing deep

green crystals, suitable for X-ray diffraction studies.


Crystal structure of copper-complex


To establish unequivocally the geometry of the above

condensation product, the crystal structure was determined by

X-ray diffraction. A well shaped crystal of 0.78 x 0.34 x

0.034 mm size was used for intensity measurements on Nicolet

P1 bar diffractometer with Ni filtered-CuKa radiation.

Reflections were collected in the 20 range 1.5-112.50 using

the 0-20 scan mode and a variable scan speed (1.90-29.300

min-'). Two check reflections measured after every 48 reflec-

tions showed an intensity variation of 5%. Of 1658 reflec-

tions measured, 1289 with I2.0a(I) were used in calculations.

Pertinent data are listed in Table 3-7.

The structure was solved by the heavy atom method. The

position of all H-atoms was located in the difference maps.

Non-hydrogen atoms were refined with anisotropic thermal

factors. The parameters of the H-atoms were included in the







58

structure factor calculations but they were not refined. The

isotropic temperature factor of 0.05 A2 was assigned to all H-

atoms. The final refinement of all parameters converged at

R=0.043 and R,=0.041 where w=a-'. The residual peaks in the

final difference map were in the range from -0.44 to 0.33 eA3.

All calculations were carried out using the DESK TOP SHELXTL

(Nicolet, 1986). Crystal data are summarized in Table 3-7

through 3-12. The structure is illustrated in Figure 3-6.


Iron(III) Complex


Synthesis of iron-complex


The 2,2'bis-(salicylideneamino)biphenyl (0.392g, 1.0 x

10-3 mol) in 50 mL methanol at about 400C was stirred until the

ligand was dissolved completely. Sodium methoxide (0.108g,

2.0 x 10-s mol) in 20 mL methanol was added to the methanol

solution and stirred for about 1 hour. Iron(III) nitrate

(0.404g, 1.0 x 10-3 mol) was added to the methanol solution,

forming a deep brown solution. The brown solution was

refluxed for about 8 hours, cooled and filtered. Slow

evaporation of the brown filtrate produced deep brown

precipitate. The solid was washed with water and filtered,

giving a deep brown powder. The weight of this product

corresponded to a yield of 52% of theoretical. The elementary

analysis showed:

C % H% N %

Found: 65.78 4.48 7.13

Calculated: 65.54 4.13 7.17.










TABLE 3-7

Crystal Data for [C26HiN202-Cu]


[Cz2eHsN202Cu]


Molecular Weight

Crystal System

Space Group

a, A

b, A

c, A

a, deg

, deg

1, deg

Volume, A3

Z


454.0

Orthorhombic

P nna

16.949(3)

13.188(3)

9.369(1)

90 *

90 *

90 *

2094(1)

4


d(calcd), g/cms 1.44

Crystal Size, mm3 0.78 x 0.34 x 0.034

Radiation Used CuKa

A, cm-1 16.33

28 Range, deg 1.5-112.5

Number of collected data 1658

Data with I2.0oI 1289

Goodness of Fit 4.943

R, % 4.32

R, % 4.09

* Required by symmetry of space group


Formula











TABLE 3-8

Final Positional Parameter (x 104) and Isotropic
Thermal Parameters (AIxl03) for the Cu[(sal)2bp] Complex



ATOM X Y Z U*


C(1)

C(2)

C(3)

C(4)

C(5)

C(6)

N(1)

C(7)

C(8)

C(9)

0(1)

C(10)

C(11)

C(12)

C(13)


4831(1)

2797(2)

3386(2)

3312(2)

2655(3)

2066(2)

2144(2)

4075(2)

4233(2)

4920(2)

5591(2)

5642(1)

6242(2)

6213(3)

5561(3)

4931(3)


7500

7281(3)

6647(3)

6224(3)

6420(3)

7047(3)

7466(3)

6418(2)

5460(3)

5033(3)

5618(3)

6598(20

5101(3)

4076(3)

3503(3)

3970(3)


2500

1759(4)

1220(4)

-123(5)

-954(5)

-436(5)

897(4)

2050(3)

2242(4)

2876(4)

3259(4)

3040(3)

3863(4)

4116(5)

3746(5)

3133(5)


31(1)

33(1)

31(1)

42(1)

53(2)

49(2)

41(1)

31(1)

37(1)

35(1)

36(1)

41(1)

43(1)

49(2)

50(2)

50(2)


* Equivalent isotropic U defined as one third of the trace
of the orthogonalised Uy tensor











TABLE 3-9

Bond Distances (A) for the Cu[(sal),bp] Complex


Bond Distances (A)


Cu-N(1)

C(7)-N(1)

C(1)-C(2)

C(2)-C(3)

C(4)-C(5)

C(7)-C(8)

C(8)-C(13)

C(9)-C(10)

C(11)-C(12)

C(1)-C(1')


1.964(3)

1.305(5)

1.397(5)

1.383(6)

1.384(6)

1.422(5)

1.423(6)

1.415(6)

1.383(6)

1.503(7)


Cu-O(l)

C(9)-0(1)

C(1)-C(6)

C(3)-C(4)

C(5)-C(6)

C(8)-C(9)

C(9)-0(1)

C(10)-C(11)

C(12)-C(13)


1.887(2)

1.321(5)

1.391(5)

1.383(6)

1.371(6)

1.421(5)

1.321(5)

1.373(6)

1.360(6)











TABLE 3-10

Bond Angles (0) for the Cu[(sal),bp] Complex


Bond Angles (0)


N(1)-Cu-O(1)

0(1)-Cu-N(1A)

0(1)-Cu-O(1A)

C(2)-C(1)-C(6)

C(6)-C(1)-C(1A)

C(1)-C(2)-N(1)

C(2)-C(3)-C(4)

C(4)-C(5)-C(6)

Cu-N(1) -C(2)

C(2)-N(1)-C(7)

C(7)-C(8)-C(9)

C(9)-C(8)-C(13)

C(8)-C(9)-C(10)

Cu-O(1)-C(9)

C(10)-C(11)-C(12)

C(8)-C(13)-C(12)


94.3(1)

151.2(1)

86.5(1)

117.6(3)

118.0(3)

120.8(3)

120.6(4)

119.4(4)

119.6(2)

116.5(3)

123.1(4)

118.7(3)

117.7(4)

128.0(2)

121.5(4)

121.9(4)


N(1)-Cu-N(1A)

N(1)-Cu-O(1A)

N(lA)-Cu-O(1A)

C(2)-C(1) -C(1A)

C(1)-C(2)-C(3)

C(3)-C(2)-N(1)

C(3)-C(4)-C(5)

C(1)-C(6)-C(5)

Cu-N(1)-C(7)

N(1)-C(7)-C(8)

C(7)-C(8)-C(13)

C(8)-C(9)-0(1)

0(1)-C(9)-C(10)

C(9)-C(10) -C(11)

C(11)-C(12)-C(13)


98.5(2)

151.2(1)

94.3(1)

124.3(3)

120.4(3)

118.8(3)

119.7(4)

122.3(4)

122.7(4)

127.5(3)

118.2(3)

123.1(3)

119.1(3)

121.0(4)

119.1(4)











TABLE 3-11

Anisotropic Thermal Parameters (A2xlO3)
for the Cu[(sal),bp] Complex


U11 U22 U33 U23 U1 U12


47(1)

43(2)

41(2)

52(3)

50(3)

56(3)

51(3)

43(2)

54(3)

50(3)

33(2)

67(2)

50(3)

49(3)

61(3)

69(3)


26(1)

31(2)

29(2)

39(2)

57(3)

60(3)

47(2)

28(2)

29(2)

26(2)

41(3)

28(2)

44(3)

45(3)

31(2)

35(2)


21(1)

27(2)

25(2)

34(2)

52(3)

32(2)

24(2)

21(2)

28(2)

28(2)

33(2)

26(1)

36(2)

53(3)

59(3)

45(3)


0

-5(2)

-6(2)

-2(2)

-9(2)

-2(2)

0(2)

-1(1)

-6(2)

5(2)

8(2)

1(1)

10(2)

26(2)

13(2)

1(2)


0

2(2)

-0(2)

-0(2)

-8(2)

-12(2)

-4(2)

-2(1)

4(2)

5(2)

2(2)

-11(1)

-2(2)

4(2)

4(3)

9(2)


2(1)

4(2)

2(2)

-7(2)

-6(3)

5(3)

1(2)

-0(1)

-3(2)

4(2)

4(2)

7(1)

0(2)

11(2)

7(2)

1(2)


The anisotropic temperature factor exponent takes the form:

-2z (h a U*U+k2b*2U22+1 c*2 U3+2klb c U23+2hla c*U,3+2hka*b*UI2)


Cu

C(1)

C(2)

C(3)

C(4)

C(5)

C(6)

N(1)

C(7)

C(8)

C(9)

0(1)

C(10)

C(11)

C(12)

C(13)











TABLE 3-12

H-Atom Coordinates (x 104) and
Isotropic Thermal Parameters (Ax103)
for the Cu[(sal)2bp] Complex


ATOM X Y Z U


H(3) 3779 5787 -475 50

H(4) 2647 6139 -2079 50

H(5) 1567 7211 -1007 50

H(6) 1701 7910 1318 50

H(7) 3815 4824 1869 50

H(10) 6715 5534 4202 50

H(11) 6671 3695 4523 50

H(12) 5505 2669 3975 50

H(13) 4432 3617 2898 50
























C30

co
U

a-4

0,r-i
0o


4J
<"
^

U)


u)
r.
.rj
4




4)

44
03
0

> .0
4J
SUl





0
(, .


J4
c! <"




3

,C
cr^
m








66















f




a



I(11








o
Ut







67

The products were recrystallized from benzene, producing deep

brown crystals, suitable for X-ray diffraction studies.


Crystal structure of iron-complex


To establish unequivocally the geometry of the above

condensation product, the structure was determined by X-ray

diffraction. A well shaped crystal of 0.32 x 0.20 x0.04 mm

size was used for intensity measurements on a Siemens R3m/E

diffractometer with graphite monochromat, MoKa radiation.

Reflections were collected in the 20 range 3.0-52.00 using the

0-20 scan mode and a variable scan speed (1.90-29.30 min-').

Two check reflections measured after every 98 reflections

showed an intensity variation of 5%. Of 5124 reflections

measured, 2217 with I3.0a(I) were used in calculations.

Pertinent data are listed in Table 3-13.

The structure was solved by the heavy atom method. Non-

hydrogen atoms were refined with anisotropic thermal factors.

The benzene ring (the solvent molecule) was fixed as a rigid

body. The parameters of the H-atoms were included in the

structure factor calculations but they were not refined. The

isotropic hydrogen temperature factor U of 1.2 was assigned

to all H-atoms. The final refinement of all parameters

converged at R=0.086 and R,=0.092 where w=a-2. The residual

peaks in the final difference map were in the range from -0.67

to 0.89 eA-3. Crystal data are summarized in Table 3-13







68
through 3-18. The structure is illustrated in Figure 3-7 and

Figure 3-8.


Description and Discussion

Nonplanar Ligand


The bright yellow crystal of formula IC26H2Nz202] was

determined to have a triclinic unit cell of space group P1 bar

and da,,d=l.27g/cmS. Final positional parameters for the atoms

are given in Table 3-2. Table 3-3 and 3-4 contain the bond

lengths and bond angles, respectively. The deviations of the

N-H.....O angles from 1800 and the long H.....N and 0.....N

distances are characteristic of intramolecular hydrogen bonds

(Table 3-4).

The C-N bonds of salicylidene linkages ( C(7)-N(1)

1.300(4) A; C(7')-N(1') 1.288(6)A ) are both shorter than the

neighboring C-N bonds ( C(2)-N(1) 1.412(7) A; C(2')-N(1')

1.431(5) A ). This indicates the bonds between N and C of

salicylidene linkages (imine bonds) are characteristic of

highly localized double bonds.

The equations of various planes are presented in Table

3-19 and the deviations from these planes are shown in Table

3-20. These results reveal that the four phenyl rings are

quite planar, but twisted relatively to each other ( from 290-

670 ). Obviously, any attempt to make the biphenyl group

coplanar would result in intolerably close contact between

the two hydrogen atoms. The twisted ligand conformation

results from the minimization of these nonbonding repulsions.







69

TABLE 3-13

Crystal Data for [C2eH,,N,2Fe]NO3.CegH


[C2,H,,N2,OFe] NO3.C CeH


Molecular Weight

Crystal System

Space Group

a, A

b, A

c, A

a, deg

f, deg

-, deg

Volume, A3

Z

d(calcd), g/cm3

Crystal Size, mm3

Radiation Used
A I cm-1
jn, cm'

20 Range, deg

Number of collected data

Data with 13.0aI

Goodness of Fit

R, %

Rw %


586.1

Monoclinic

P 21/n

10.887(4)

18.462(5)

14.142(3)

90*

98.27(2)

90*

2813(1)

4

1.67

0.32 x 0.20 x 0.04

MoKa

5.78

3.0-52.0

5124

2217

1.346

8.59

9.22


* Required by symmetry of space group


Formula











TABLE 3-14

Final Positional Parameter (x 104) and
Isotropic Thermal Parameters (A'xlOs)
for the Fe[(sal),bp)]NO Complex


X Y Z U*


[C26HN2,02Fe ]


2200(3)
3009(18)
3527(15)
4767(17)
5558(22)
5068(22)
3838(22)
2760(13)
2407(16)
1875(15)
1954(19)
2307(12)
1587(18)
1135(20)
995(18)
1411(19)
1712(17)
1197(16)
-53(19)
-759(19)
-234(18)
983(18)
1886(13)
2343(18)
3088(19)
3660(18)
3515(12)
4395(22)
4623(24)
4134(22)
3359(19)


5668(1)
3666(10)
4271(9)
4275(11)
3703(12)
3109(12)
3104(9)
4882(7)
4891(10)
5509(8)
6211(9)
6334(6)
6798(11)
6684(14)
5993(12)
5423(11)
3650(9)
4153(10)
4128(8)
3524(11)
3005(10)
3055(9)
4778(7)
4762(9)
5286(11)
5863(8)
5958(7)
6332(11)
6266(13)
5681(15)
5218(11)


7385(2)
7713(10)
8240(10)
8617(11)
8479(15)
7972(16)
7606(11)
8403(9)
9235(11)
9662(11)
9237(13)
8415(7)
9790(13)
10631(14)
10947(13)
10511(12)
7291(9)
6644(11)
6223(14)
6406(15)
7030(12)
7456(12)
6408(9)
5604(11)
5279(12)
5843(12)
6747(8)
5463(15)
4544(20)
3975(16)
4355(12)


Fe
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
N(1)
C(7)
C(8)
C(9)
0(1)
C(10)
C(l1)
C(12)
C(13)
C(1')
C(2')
C(3')
C(4')
C(5')
C(6')
N(1')
C(7')
C(8')
C(9 )
0(1 )
C(10')
C(11')
C(12')
C(13')


45(1)
48(7)
35(6)
42(7)
64(9)
61(9)
41(8)
38(5)
43(7)
34(6)
51(8)
52(5)
57(8)
70(10)
56(9)
58(8)
41(7)
42(7)
50(8)
59(8)
57(8)
42(7)
42(5)
47(7)
57(8)
37(7)
55(5)
75(10)
95(13)
90(11)
64(9)










TABLE 3-14 Continued


X Y Z U*


NO3-

N -75(17) 6058(9) 6766(10) 70(7)
On(l) 200(12) 5583(7) 7407(9) 64(5)
On(2) 880(14) 6307(7) 6425(8) 68(6)
On(3) -1110(16) 6238(10) 6437(12) 121(8)


C6He

C(1E) 5878(21) 8692(10) 3525(15) 127(17)
C(2E) 5652 8251 4281 131(18)
C(3E) 6634 7896 4836 123(16)
C(4E) 7843 7983 4634 87(12)
C(5E) 8069 8424 3878 81(11)
C(6E) 7087 8779 3323 97(13)



* Equivalent isotropic U defined as one third of the trace
of the orthogonalised Ui, tensor







72

TABLE 3-15

Bond Distances (A) for
the Fe[(sal),bp)]NO Complex


Bond Distances (A)


Fe-O(l)

Fe-On (1)

Fe-N (1)

C(1) -C(2)

C(2)-C(3)

C(3)-C(4)

C(4)-C(5)

C(5)-C(6)

C(6)-C(1)

C(2)-N(1)

C(7) -N(1)

C(7)-C(8)

C(8)-C(9)

C(9)-C(10)

C(10)-C(11)

C(11)-C(12)

C(12)-C(13)

C(13)-C(8)

C(9)-0O(1)

C(1)-C(1')

On(2)-N


1.987(11)

2.188(14)

2.074(12)

1.515(23)

1.397(24)

1.393(30)

1.376(31)

1.364(32)

1.398(28)

1.442(21)

1.289(21)

1.449(24)

1.437(22)

1.428(27)

1.368(29)

1.367(33)

1.332(29)

1.377(25)

1.296(23)

1.452(25)

1.292(23)


Fe-O(1')

Fe-On(2)

Fe-N(1')

C(1')-C(2')

C(2')-C(3')

C(3')-C(4')

C(4')-C(5')

C(5')-C(6')

C(6')-C(1')

C(2')-N(1')

C(7')-N(1')

C(7')-C(8')

C(8')-C(9')

C(9')-C(10')


C(10')-C(13')
C(11')-C(12')

C(12')-C(13')

C(13')-C(8')

C(9')-O(1')

On(l-)N

On(3)-N


1.876(14)

2.176(13)

2.143(14)

1.367(22)

1.406(26)

1.400(27)

1.371(27)

1.337(26)

1.394(25)

1.441(23)

1.305(22)

1.383(27)

1.419(24)

1.344(29)

1.362(36)

1.406(35)

1.365(34)

1.386(26)

1.323(21)

1.267(20)

1.202(24)











TABLE 3-16

Bond Angles (0) for
the Fe[ (sal) bp) ]NO Complex


Bond Angles (0)


O(1)-Fe-O(l')

0(1')-Fe-On(l)

0(1')-Fe-On(2)

0(1)-Fe-N(1)

On(l)-Fe-N(1)

O(1)-Fe-N(1')

On(1)-Fe-N(1')

N(1)-Fe-N(1')

C(13)-C(12)-C(11)

C(11)-C(10)-C(9)

C(10)-C(9)-0(1)

C(13)-C(8)-C(9)

C(9)-C(8)-C(7)

C(5)-C(6)-C(1)

C(5)-C(4)-C(3)

C(3)-C(2)-C(1)

C(1)-C(2)-N(1)

C(6)-C(1)-C(1')

C(8' ) -C(7' )-N(1')


102.6(5)

149.0(5)

91.5(5)

86.6(5)

97.6(5)

168.2(6)

83.5(5)

85.1(5)

121.7(19)

121.6(20)

120.0(15)

121.4(16)

118.9(16)

124.6(17)

118.5(21)

120.1(16)

120.4(14)

123.0(16)

126.1(15)


O(1)-Fe-On(1)

O(1)-Fe-On(2)

On(1) -Fe-On(2)

O(1')-Fe-N(1)

On(2)-Fe-N(1)

0(1')-Fe-N(1')

On(2) -Fe-N(1')

C(12)-C(13)-C(8)

C(12)-C(11)-C(10)

C(10)-C(9)-C(8)

C(8)-C(9)-0(1)

C(13)-C(8)-C(7)

C(8)-C(7)-N(1)

C(6)-C(5)-C(4)

C(4)-C(3)-C(2)

C(3)-C(2)-N(1)

C(6)-C(1)-C(2)

C(2)-C(1)-C(1')


89.3(5)

95.2(5)

58.6(5)

111.4(6)

156.1(6)

88.3(5)

89.0(5)

120.3(18)

119.9(21)

114.7(17)

125.3(16)

119.4(15)

125.4(15)

119.2(21)

122.2(17)

119.4(14)

115.4(16)

121.6(16)


C(5')-C(6')-C(1') 120.9(16)











TABLE 3-16 Continued


Bond Angles (0)


C(6')-C(5')-C(4')

C(4 )-C(3')-C(2')

C(3')-C(2 ')-N(1')

C(1)-C(1')-C(6')

C(6')-C(1')-C(2')

C(13')-C(12')-C(11')

C(11')-C(10')-C(9')

C(10')-C(9')-0(1')

C(7') -C(8' ) -C(13')

C(13 ')-C(8' ) -C(9')

Fe-O(1')-C(9')

Fe-On(2)-N

On(1) -N-On(3)

Fe-N(1')-C(7)

C(7)-N(1)-C(2)

Fe-N(1')-C(2')


121.4(18)

118.2(16)

115.6(14)

119.4(15)

117.4(16)

117.4(22)

121.6(20)

117.5(15)

117.6(17)

117.6(18)

129.2(11)

94.0(10)

125.5(18)

121.9(11)

114.3(13)

120.3(10)


C(5')-C(4')-C(3')

C(3')-C(2')-C(1')

C(1') -C(2')-N(1')

C(1)-C(1')-C(2')

C(12')-C(13')-C(8')

C(12')-C(11')-C(10')

C(10')-C(9')-C(8')

C(8')-C(9' )-0O(1')

C(7')-C(8')-C(9')

Fe-O(1)-C(9)

Fe-On(l)-N

On(1) -N-On(2)

On(2)-N-On(3)

Fe-N (1)-C(2)

Fe-N(1')-C(7')

C(7')-N(1')-C(2')


119.1(18)

122.6(17)

121.5(15)

122.8(16)

122.8(19)

120.6(24)

119.8(17)

122.7(16)

124.7(16)

125.5(11)

94.2(11)

113.2(15)

121.1(16)

123.7(10)

122.2(11)

117.4(14)












TABLE 3-17

Anisotropic Thermal Parameters (Axl03)
for the Fe[(sal)2bp)]NO3 Complex


Ull U22 Ug3 U23 U1 U12


C26HIeN202Fe


Fe
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
N(1)
C(7)
C(8)
C(9)
0(1)
C(10)
C(11)
C(12)
C(13)
C(1 )
C(2 )
C(3')
C(4')
C(5 )
C(6')
N(1')
C(7')
C(8')
C(9')
0(1 )
C(10')
C(11')
C(12')
C(13')


68(2)
67(16)
46(12)
49(13)
78(19)
46(17)
69(17)
55(10)
39(13)
34(12)
79(17)
78(11)
61(16)
82(19)
59(16)
80(18)
73(15)
24(12)
68(16)
37(14)
67(16)
51(15)
37(10)
84(16)
72(16)
59(14)
82(11)
121(22)
107(23)
88(19)
85(18)


34(1)
63(12)
34(9)
45(11)
54(14)
55(15)
25(10)
17(7)
56(12)
25(10)
24(10)
40(8)
63(14)
90(19)
88(17)
63(14)
41(10)
63(14)
13(9)
60(14)
57(13)
32(10)
51(10)
30(10)
65(13)
16(9)
56(8)
57(14)
69(18)
120(21)
68(15)


32(1)
10(7)
24(8)
31(8)
64(13)
88(16)
38(10)
41(8)
35(10)
42(9)
48(11)
36(6)
44(12)
36(12)
28(10)
37(10)
8(7)
36(9)
70(13)
76(14)
50(11)
43(10)
37(8)
31(9)
28(13)
42(10)
35(7)
62(14)
121(22)
67(15)
40(11)


-5(1)
-12(9)
0
-5(9)
1(12)
28(13)
3(8)
4(6)
26(9)
0
-10(9)
-2(6)
6(10)
-7(12)
4911)
-17(10)
0
-7(9)
-2(9)
0
-31(10)
1(8)
7(7)
4(8)
8(9)
-1(7)
-1(6)
-33(12)
-19(16)
-6(17)
-4(10)


2(1)
-9(9)
0
3(9)
25(13)
26(13)
36(11)
-0(7)
4(9)
0
-1(11)
-0(6)
1(11)
3(12)
24(10)
25(11)
0
-10(9)
18(12)
0
23(11)
11(10)
-1(7)
16(10)
-10(10)
25(10)
30(7)
67(15)
58(18)
33(14)
14(11)


-0(2)
18(12)
0
-16(12)
-7(14)
34(13)
-3(11)
7(7)
-1(10)
0
8(10)
-9(7)
16(12)
33(15)
9(13)
16(12)
0
7(10)
15(9)
0
-52(12)
-12(10)
-2(8)
-1(10)
-3(12)
-5(9)
-23(7)
-28(14)
-40(16)
-7(18)
-11(13)










TABLE 3-17 Continued


Ul U22 Us, U,, U,1 U12

NO3-

N 109(16) 74(12) 25(8) 0 0 0
On(1) 54(10) 62(9) 75(9) -23(8) 12(7) -4(7)
On(2) 90(12) 64(9) 50(8) 8(7) 4(7) 19(8)
On(3) 92(14) 156(17) 94(12) -30(12) -53(10) 54(12)


C6H6
C(1E) 132(32) 64(20) 162(33) -59(22) -56(23) 56(19)
C(2E) 37(19) 188(37) 162(32) 0 0 0
C(3E) 158(33) 145(28) 81(19) -71(20) 62(23) -98(26)
C(4E) 106(25) 74(18) 72(18) -14(14) -20(16) -8(16)
C(5E) 92(22) 80(18) 77(17) -28(14) 35(17) -33(16)
C(6E) 156(31) 68(18) 62(16) -9(13) 3(200 -25(21)


The anisotropic temperature factor exponent takes the form:

-2 r(h2a *2U,+k2b*2U22+12c *2U+2klb*c*U23+2hla c U+2hka*b Ul2)












TABLE 3-18

H-Atom Coordinates (x 104) and
Isotropic Thermal Parameters (Axl03)
for the Fe[(sal)2bp)]NO, Complex


ATOM X Y Z U


1389
585
916
1660
3520
5585
6423
5097
2143
1337
-721
-1602
-412
2984
4337
5121
4770
5202
4820
6478
8518
8900
7242
2632(127)


4950
5917
7089
7285
2685
2702
3723
4685
4348
2675
2597
3473
4514
4828
5609
6622
6724
8936
8191
7592
7739
8484
9082
4544(68)


10791
11496
11000
9566
7250
7875
8733
8987
5200
7873
7173
6101
5820
3967
3343
4282
5847
3143
4420
4357
5016
3739
2802
9699(93)


H(1A)
H(1A)
H(3A)
H(4A)
H(1B)
H(2B)
H(3B)
H(4B)
H(2)
H(1C)
H(2C)
H(3C)
H(4C)
H(1D)
H(2D)
H(3D)
H(4D)
H(1E)
H(2E)
H(3E)
H(4E)
H(5E)
H(6E)
H(1)


70
66
80
64
46
71
83
48
52
45
57
61
61
76
98
112
94
80
80
80
80
80
80
32


























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TABLE 3-19

Equations to Various Planes
for 2,2'-bis(salicylideneamino)biphenyl


Plane* Atoms 1 m n p



Salicylidene Benzene Ring:

1 C8 C9 C10 C11 C12 C13 .8125 -.4880 -.3188 4.6905
2 C8'C9'C10'C11'C12'C13' .2234 -.2926 .9298 9.2862

Biphenyl Ring:

3 C1 C2 C3 C4 C5 C6 -.4295 .8835 .1870 -3.0985
4 C1'C2'C3'C4'C5'C6' .6438 -.3055 .7015 9.4751

Imine Region:

5 N1 C7 C8 C9 01 .8095 -.4911 -.3219 4.6348
6 N1'C7'C8'C9'01' .2077 -.3109 .9275 9.1459



Angles of interest between the planes (0) (plane 1 plane 4)
1-3=32.9 3-4=65.5 4-2=27.7

X + mY + nZ = p
Reference is made to orthogonal X, Y, Z.










TABLE 3-20
Distances (A) to Various Planes in TABLE 3-19
for 2,2 -bis(salicylideneamino)biphenyl


Plane Atoms Deviation (A)

1 C8 C9 CI0 Cl1 C12 C13 N1 C7
-.0036 .0036 -.0019 .0002 -.0003 .0002 -.0124 .0121
2 C81 C9' CI0' Cl1' C12' C13' N11 C7'
-.0017 .0032 .0019 -.0087 .0103 -.0049 -.0449 -.0494
3 C1 C2 C3 C4 C5 C6 N1 C7
.0058 -.0057 .0019 .0017 -.0015 -.0023 -.1434 .3096
4 Ci' C2' C3' C4' C5' C6' NI' C7'
.0013 -.0106 .0119 -.0039 -.0054 .0068 .0196 -.4914
5 NI C7 C8 C9 01 C2
-.0066 .0109 -.0085 .0021 .0020 .0993
6 N1' C7' C8' C9' 01' C2'
-.0004 -.0052 .0121 -.0128 .0065 .0375







84

The highly localized imine double bonds together with the

biphenyl backbone make the molecule incapable of functioning

as a planar quadridentate. In contrast, in 2,2'-bis (2'-

pyridylmethylamino)biphenyl copper'46 (Figure 3-9), the ligand







N

N
N





Figure 3-9 2,2'-bis(2''-pyridylmethylamino)biphenyl



was functioning as a planar quadridentate. Flexibility can

be introduced easily by the reduction of imine bonds.

A model (Figure 3-10) shows that the two oxygen atoms and

the two nitrogen atoms of 2,2'-bis-(salicylideneamino)biphenyl

can be brought almost strainlessly into a tetrahedral

arrangement from which they can all become attached to a

central metal atom of appropriate size. Moreover, they cannot

be disposed about a metal atom in a planar arrangement. It

means the ligand (sal)2bp is a good candidate as a nonplanar

ligand.

















N


Figure 3-10 A Model of Strainless Tetrahedral
Arrangement for (sal)2bp