Title: Synthesis of charged and neutral boron-containing heterocyclic systems
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00097653/00001
 Material Information
Title: Synthesis of charged and neutral boron-containing heterocyclic systems
Physical Description: x, 106 leaves. : illus. ; 28 cm.
Language: English
Creator: Abate, Kenneth, 1944-
Publication Date: 1971
Copyright Date: 1971
Subject: Boron   ( lcsh )
Heterocyclic compounds   ( lcsh )
Chemistry thesis Ph. D
Dissertations, Academic -- Chemistry -- UF
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
Thesis: Thesis--University of Florida, 1971.
Bibliography: Bibliography: leaves 103-105.
Additional Physical Form: Also available on World Wide Web
General Note: Manuscript copy.
General Note: Vita.
 Record Information
Bibliographic ID: UF00097653
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: alephbibnum - 000943506
notis - AEQ5201
oclc - 016665008


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Synte- sis ;- Ch ed a ,'d ,Neu--ali
3oro;--Con;'"aini r g 1 .' -.or ,cyc lic Systems

3y E

.c'TlET;w A L i:


r\ j~I~1Z~; ?

U ,, L CClH i 0,

,, ;-i:: )=0 -, ;- ('F



To my parents, Dona d and Irene Abate.

q ~ Sr'L 'I

-he author wishes

)r. r E.

kir duri

fri nd.


;C i


h eliI

V3 a --1;c

;-irst dr-f1 of this dissertation

erul I, an hi and evo r',-

Cha i r r ,

f in ri,

A i sor bu

ecia ti on o his

erc cUrs t-,

Ch "niT: .cre



e en

e Un i

whiie a

nd 3ill

r ir

;rs or



thina for the author.

Last, but by no mcans least, he auThor would d I ike tc acknow-

ledge the support and enc-jr' :- =nt offered by his parents and grand-

parents throughout the course of his college education.


:T . . . . . . . . . . . . . . . . . . . . . . . .
VCG;'? 5


r duct ion ................................

er;3 and Instrur- l n ti n ...............

i m e ta I ......... ... .... ............... .

S s i s . . . .. . .. .. . .. .. . . . . . . .

u ure f .............................

robora i e ir ents ...................

ic a s . . . .. .. .. .. .. .. ..

S. . . . . . . . . . . . . . . . . . . . .

S. . .. . . . . . .. . . . . . . . . . . .. .

H . . . . . . . . . . . . . . . . . . .. .
2~I3U re~

CU f-i.

I .



V .

V. Dis

S'Y ...




V i








L 1 ,




Table No.











pKa Determination of dihydro (2,2'-
iminodipyridinatc)(1-)-N ,yN lboron-
dihydro(2,2'-iminodipyridine-N i ,N1 ')

pKa Determination of diflucro[(2,2'-
iminodipyridanato)(1-)-N ',N1']boron -
di f I uoro(2,2'- imi nod i pyr id i ne-N1 I,iI N1
boron(1+) chloride

pKa Determination of fluor-ohydro[(2,
2'-iminodipyridinato)( 1-)-N1, ]
N1, N ')boron(1)chlcride(l -)

'ass Spectra Data

Proton NMR Data of PF6 Sal ts

Prcton NMR Data of Halide Salts

Proton :'.P Data of Neutral Adducts

11B NMR Data of Salts and Neuti-al Adducts

19F MR Data of Fluorinated Compounds

ace e











r iure i it e IiP

i n. on (1+)
C O 1 E : ic ) a i .. o (2,2 '-
:r i i:; r i:,, i .. ,1 ] ') ....1+ )

:c )
( c ; i .d i : : i- .... ) '

1 -' i p i ,i, 1 ) j :" t
SI i r i

Abstract of Dissertation Presented -o the
Graduate Council of the University of Florida in Par+ial Fulfillment
of the Pequirmcrrents for the Degree of Doctor of Philosophy



Kenneth Abate

December, 1971

Chairmrn: Professor G. E. Ryschkewitsch
i.!a i..r Department: Chernistry

Trirmthylamine monoicdoborane was reacted with 2,2'-dipyridyl-

amine in an aTtempt not only to get halide displacement but Ialso trans-

armination to produce a cyclic boron cation (I).

H + H +2


This cad ion, dihydro (2,2'-i nodipvrid ie-N ,N boron (1+), was pre-

pared and was the basic structure for all subsequent attempts to pre-

pare a charged heteroc-yclic aromatic system (Il).

idro (2,2'- iiinodipyridine-N1, 1 ) boron (1+) appeared to

be the ;ideal syi ,;-e; ;- already lad four ieen electrons avai lable for


l- liati i f he ri g r. nr r en nd -e -crc coud be -ade sp

*Dridized. ,.3s hoped 1 J-he cation (1) ,,;jld el )-inate I-i
)r d Pa t he

tipcnl -cusly to odue ( ) u This did no- ,ccur o their reac-

tions ,cC-e a1- ed. s icus rctio a ,) (

eI i .I i g: i I

uce a +b .I,

o be a be"; cr

N .l I

ion .


racti ^

s i I

ihaI e t.I

seV)d hi

( IV). hi


i: i t'r c r i (


trigona !f the instability of the heteroaroa! ic system (II) v..as d,.,

TO the plus --wo cha-_: on it, the heterearo r t ic system formed (I II) \

hydride abstraction from (IV) would only develop a plus one charge and

possibly b. more stable. Again, evidence for hydride abs-raction ;:zs

obtained but no heteroarcrmanic system was isolated.

The reactivity of the bri '_ nitrogen in the neutral zwitter-

icn w.as irvesti-ted. :th neutral and char_ ed -is ,,orec isolated

with groups -t-ached to the nitrc- n. As a consequence of h:s .ork,

Ssynthesis for the preparTi i- of 2,2'-dipyr idy lit was -


.rly sixties, th

i i ri Ie in 1


. *) a

-O R

R = OH, CcH5


I !r ad-f

r',jt i

-. S
r-~ ---

'" -TER I

rir T'2 7,z f;i 'i

I ow.

These compounds, when compared to corresponding open-chain analogs,

showed an increase in stability toward h'ydrolysis. A limited number

were stable in acids or bases but few approached the stability of their

carbon analogs. In general, the ones containing B-N bonds were more

stable than those containing B-0 or B-S bonds.

Concomitant with the development of boron-containing hetero-

aromatic systems, four coordinate boron cationschemistry came into ex-

istence. Beginning with the classical work of Parry and co-workers

(4-9) on the structure of the "diammonate of diborane" and due to the

work of researchers such as Mikhailov, Noth, Douglass, Muetterties and

Ryschkewitsch, boron cation chemistry has rapidly developed and several

good reviews have been written (10-12). A few examples of boron cautions

are listed according to the number and kinds of ligands attached to

boron and ascending charge type.

(base)2BH2- (17,22,25,26,30) base = NH N(CH ) ,

P(CH )3, S(CH)2,

As(CH3)3, C5H5N

(dibase)BH2 (13,27,34) dibase = dipyridyl,
(CH ) NCH CH2N(CH3)2

(TMED), (CH3)-


(base)2BX2 (21,25,31,32) (3CI-C5H 5N) BBr2

(CH ) N2BC.I2
332 *2

(di so) +-
(di ase)-"





(CH 3 )2--N N/ 'F

(base )2 BX

(di base)



X C ; base = CH5

X = CI; base = 4-picoline

X ; di

( 19, = ,23,26,(C

base = N(CI3)3

base' = P(C' ) ,

4-picc ine,

5 OS (- )2,

(18, 19,26,33)

X = CI, ?r

)ase' = 4-picoline




bass = N(CH ) ;

( .se)(Dase')3X2


X = CI

base = C5H5N

base' = NH(CH3)2




(base) i-12

(base)..>X "2


base = C H5N, 4-picoline


X = Br; base = C H N

(base)(dibase)BH12 (14)

\ -r


\ / +2
\ /wB

cibtse = dipyridyl

(" i base + ( 14, 15)
a rl

Ai lough nations h

liuandns nd Luia i v ran in


n is u

d iOSe

rTa in

Ibut- Iene-d iamine,

I 1 Ine

1 1 ,25 .

i bd ::+ i I i

ic h ar

.I sinal


i ial

i- n Iooc n I i

* r-e c 'I rcn

atom i n th

rmay share

ce 's r

-+2 ihere

riich one

n rdr for

S [irr' na

7T-e I ec i-rcr

, is &I itr

,1 C-

c I ec -on

e an

tota I

re are



i func i

: r i


1 ,+

I ca i

carbon in the ring system.

Because nitrogen has one more electron rhan does carbon, the

N ion is isoelectronic with a neutral carbon atom. Any aromatic sys-

tem in which a carbon atom has been replaced by a N+ ion will remain

aromatic; for example, pyridinium ion is isoelectronic with benzene.

Since boron has one less electron than carbon, the B ion and the neu-

tral carbon atom are isoelectronic. Replacement of a carbon atom in an

aromatic system by the B ion should produce an isoelectronic aromatic

system. No ions of this type have \et been isolated but one has been

reported and is very unstable (41).

If two carbon atoms are replaced, one by a N+ and the other

by a B, in an aromatic system, the resulting isoelectronic system

should be aror'atic. A large number of compounds have been prepared

which are derived from normal aromatic systems having a pair of carbon

atoms replaced with a B and a N

With 2,2'-dipyridylamine as the ligand, attempts to prepare a

model system which could eventually be converted into a heteroaromatic

system were made. A number of proposed reaction schemes are outlined

in the following.

If ring closure on 2,2'-dipyridylamine with a BH2 unit could

be accomplished, a three-membered fused ring system would be obtained.

Although the boron portion wouldbteterahedral, the system would have

fourteen n-electrons and would appear to be a good chemical precursor

for forming an aromatic heterocyclic system isoelectronic to anthra-

ce-ie. To accomplish this, the boron portion would have to become tri-

gona .

i'i iier dnd Muetter ies (13) prepared borane cations of the

-*neral iormnuld 2-(base)2 (base

donor-substi tted bcrane and hea

of the pe D-+ X-. Ie r erici

toward reduc ion and lar so as

res on, iodide in nd, dral

u ed. Th bi resricc in

ith 1 i -
:ithi ter ica llyi hindered d:' nrs ^

not be .red. V k .n r

pr .red a i e .1 a n

b'Cse-bor-ane rjduct, for eir :hi

a si i ar

d rtTHiE y

(20) i

c:ere hr

Cccu r.



Pr,, As

a sea ed

X- were

cO pe e e
0rn U

-, SR2) by taking a

Tuc with onium salts

fiat ihey must be stable

with ihe donor. For this

S 1 122 were

cn h donor w.as steric.

-rine, canions could

es nd sides were

:.,c0 sc ied with the

Ils wJre ci fiicul to isolate.

e if i i n di(2 2'p idinium)

D(TIA ) in a 1:1 rolar ratio

-r the cl c'ing reaction to

H +

TMABH -N 21:---


[ 'N N'


+ 2 -+TMAH


);2 I : C

/ 1I



A. B.

Muetterties also prepared cations by the following reaction

scheme: (H2BD2)+ 2D' -) (H2BD'2) + 2D. He observed experimentally

that reaction occurred most readily when the new donor (D') was a

stronger donor or one with chelating ability. One wculd therefore ex-

pect to get ihe desired product by heating (TIA)2 .- i with 2,2'-di-
2 2
pyridylamine (DPA) and get loss of two moles of TIA and forrmtion of A

and, perhaps, B.

Two other alternate methods which involve trimethyiamine-

monoiodoborane (TI'ABH21) and trimeihylamine-diiodoborane (TMASHI2)

appeared feasible.

C N + ,.-NF
TMABHZ + DPA --> I i T
,B H


TM AB i-12 -- DPA --





B TMAH + 2 I

f ring clo ure v.;re acccrplished ct forn a caticn (A) but

arc 'i i -y ymir i n,
aroTa t i y .ere not obtained '.3neous I ly h 're el iminaticn,

here would a numbr of si ic hni vhich could be usd o

form -he desired aro r ic hetde-o le. I -ide abs ract ion, vith tri-

; ; cny i .e ,I lora ec,c .ul ibl '*e used io c ain a tr; al

coron A.L-r the cisadva aoe of T-his :rCooed ulf be ie de *Ie ;nT of

a pl

H1- H

I + 10CCIO4-> + CIO4 + CH



ihe development of a plus two charge would probably facili-

le prcton loss frcn C to procuce 3. Any number of bases could be

used +c ncrorplish this. The only ra jor restriction would be that the

e s'oiJ be srerically hindered so that it could not easily coordi-

-I- 2 J7

ir .

nate to the boron portion. Diisopropylethylamine (DIEA) would be a

good base to use.

N-1-2 +V^ +


If the systems containing a B-H bond cannot be formed, per-

haps a halogenated analog could be prepared. A halogen attached to the
boron portion could share a pair of its non-bonded electrons with the

boron and help stabilize the system.

Synthesis of a halogenated boron cation could be effected by

either direct halogenation of the cation (A) or ring closure starting

with a boron trihalide and 2,2'-dipyridylamine.


I+ I 4- 2X, -> 1 + 2HX
-B, 11B
(X= Br,CI)



BX3 -- DPA -- + X-
[1 '! n, -x

A '' ic ar -~ ic s -t cod n.I 3e achieved bv alide loss.

Ir ine were able To ncnha lccat s tht 7e KcrCnw.as

bonded o r i s I :s a a id and a h. he recnique of

hydride ss raction coula in ae awt ed to produce a heteroaro-
h *rico rc h I roaro-

liiC syse.


iij I X e--> Ifl l a h

ani. y h as iod in tai .
?i1 H X H


I (E)
Ar-emps to pr, r hi srer i ---rO t jnhixhi ace

S^^K^ ll h

i ^ iv fY.*rii. h ,as s+'i-sid iii deTa i I



i- water ia I s

Cylinder gases were obtained from V1atheson Company and were

used for the most part ,iiiThout furTher purification.

A lonium hexafluorophosphate ,'.:as obtained from i rk-Pahoning

Compan /.

Amine-boranes were obtained from Callery

were used without further purification.

2,2'-Dipyridylar-ine ,'as suppl ied oy either

C -, yInc. cr Reilly Tar and Chemical CorporaTion

out further purification.

Sodium borchydride was obtained from K.e:al

. ical Copany and

Aldrich Chemical

:nd was used with-

Hydrides, Inc. in

good purity.

All solvents except 1,2-dimethoxyethane (monoglyme) and di-

ethylene glycol dimethyl ether (diglyme), supplied various commer-

cial sources, were used without purification except for drying over

calcium hydride or Molecular Sieves 3A. Monoglyme and diglyme were

stored over calcium hydride for a few days and were then fractionally

is-tilled from lithium aluminium hydride saving ,he middle 80%.


Infrared spectra were obtained on a Beckman iR-10 spectro-

-hotorrqer. :Samles v.'or prepared as Kr pel lets. Liquid amines were

if p r sible,using either sodium chloride or potassium bromide

niir --"cctra

silane as int

w ith -f Iuor

taken on a Varian A-

refetrence. 19F nm

ee as in rnal ref

- ins ~ rurent

Sspectra were

erence. B nmr

: rn trifluoride

;d n her a

e e

were n;ot correct

Ic., tra i rh

A! I



r over

S- r :i e I

ni ing vol'

rCm -

run qea


wi th

run i




Us i

a-A- I I I



1 1'
Synthesis of dihydro (2,2'-ii nodipyridine-NN ) boron

(1) iodide (1-) and hexafluoroohosphate (1-).--

TMABHV +A / 12 > TMASH2g + H2

N +
TMABH I -i- DPA > I + T MA


Into a 250 ml Erlenmeyer flask containing a magnetic stirring bar were

placed trimethylamine-borane (1.46g, 0.020 mole) and 100 ml of reagent-

grade benzene which had been dried over Molecular Sieves 3A. With

vigorous stirring, solid 12 (2.59g, 0.020 mole) was added in small por-

tions over a thirty-minute period. After each addition the flask was

loosely stoppered in order to minimize exposure to moisture yet to al-

io, hydrogen to escape. After all the 12 had reacted, there was quickly

added to the resulting reddish solution a warmed solution of 2,2'-

dipyr;dyiamine (3.42g, 0.020 mole ir 75 ml of dry benzene). Depend-

ing on the temperature of the 2,2'-d;pyridylamine solution, one could

have obtained either an immediate lightening of the solution if

the solution were hot or an ir ediate darkening of the reaction mix-

ture ocurred, and a solid was ored if the 2,2'-dip -i lamine solu-

tion was only wared. A reflux cndnser with a t-tue attached for

the flushing of ni' an a 12 drying lub .,.re quickly put into

place ad he solution was e o iust be.c reflux. As warming

oc urrd e sol ut ion Ii igtd did h util a li 'h

ysi c I s olutin rsus he su in ar i .e yamine

evolved ( nd i sc lution aAain rcare turbid. A r ,: xirately 4S

hours, no ro e tr ir:;ha eml .l and a hllc;n oIuLi"n with a

hv e I I c so id 'S lefut.

ic- C

SI )

r su ion fil-

thre m I por-

Si ion from

17 17

-hik -i

ar 178.5 .

infrared trL of he prcuct

0 ( ), (w), 2 2

)(, 1 ( 1 (s), 14 ,

1 1; 1_ 5 (w), 910, 5 (s), _5 (w),

S on nmr was run in with intern

renca and showed two u lti pets centered at

h an intensi', ratio of 3 to i repec ively.

"' nd sh ahod triplet a *6.0 O. rTpm

eherate. The solution was sturat d but

3t coupling cons ants could not be ca culate


Ad ;:bs: ions at

5, 1235 (s), 1 ,

(w), and 545 (w)

3a Tetra-ethylsilane

-8. 12 and -7.47

The 11 nmr was

from boronfri-

;he si I was so

Srendily from the

tra I ion

Tions o

so! id Y

rret i. l

sharp I

1 (s

11 1

-. i

as refe

ppm ai

run in


weak 'h




d Ic~l

'onersion to hexa f iuor-o hcs' aTe sal .--The io dide salt was

converted to The hexafluorophosphate salt in 97. 6 yield by quick pre-

cipita+ion with excess 5M, PF6 solution from a warned solution of the

iodide in 0.05%, HCI and cooling in an ice-bath. The product ',as then

filtered and dried under vacuum over CaS04. The whi e solid related at

The infrared spectrum in a K3r pelle-

showed absorption at

3370, 2495, 2440, 1690 (s), 1600, 1 (s), 13_0 (s), D3 (s-broad),
7SO (s), and 560 (s) cmr The proton nmr as run in '02 ,with in-

ernal +etrarethylsilane as reference and shoed +t.o -u!tiplets cf

qual ini'onsity which were centered at -8.27 ppr and -7.53 ppm. The

3 spectrum w.as run in CH3CrN and shced a triplet at 35.7 pp,- fr-c:

horontrifluoride etherate. The signal ,as so weak that 3-1' coupling

constant could not be calculated.

The analysis calculated for C1H, C, 5 .1; i.

3.37; N, 12.77. Fcund: C, 36.7; H, 3.41; N, 12.70.

Syn-hesis of dih .-- (2,2'-iminodipyridina o)(1-)-N ,N 1

boron.--There are two methods for the preparation of dihydro [(2,2'-

iminodipyridinato)(1-)-N ,N '] boron. The first method prepares di-

hydro [(2,2'-irminodipyridinato)(1-)-N1 ,1 ]boron by a more direct

route From trimethylamine-borane and 2,2'dipyridy!amine. The second

method is less direct but the product is purer.

(a) From 2.2'-dipvr idvIamine a rd trimchy la ne-borane.--

TM'ABH, --+ DPA ------ + H2
3" L. k bl i,


-r flask containing a

-bcrane (3.6' 0. r

d 175 ml of re t

SSieves 3A. A -er-c

s f1c at the

In-'o a

r ire t'

0 .. ;

cver '

u be f




an oran

e) r


*r n i r

./1 lI)

I'pc and 1n

luon :.as

I .c.ed as

( )


en dried under

i t he I h *-i oi f the i -ritles reno

dip idin e- ,Ni ) orn ( ) hxafuo

dissolved in 160 m of hot after and w

*,'s slowly add d. (iCare v s n

solution. the greater ,as the tence

lumps. If the solution was cool unti

noticed nd then the iaO solu ion a

ul ed.) e vas i i3a e -right

v.as cooled n a ic -ah ction fil





I id in

hff- ,i

-aer C 12.

the dihydro

.T (1-)

vigorous sftirir

here, for the

he -,duct to

very slight tur-

d.a orI granular

I cl: ec i pi ate.

.i, e d a' i-h

ra gnetic stirring bar ..ere placed

I e), 2,2'- ipyr i dylI i ne (8.5 g,

toluene .hic had been dried

Oled reflux codenser wih a t-

s se in place, and the solu-

eflux. ( id ist

ij e i7 o: Ih : ts ri-

:Jv f r :d "rs FOiSon

uti on

off cnda
so id
l id.

sol id

SJct i



(1.9 7

30 ml



T;ie :



,a3 S

Two 30 ml portions of ice cold water, and dried under ,acuur over

aCI3 The :ll '.c solid (0.94- 17.'-) relt d a- 1 -107.50

(b) Neutra I i nation of the cation.--


1 NI" a OH --+> +No I- HO

H '0 /' +'
H/rl IN] N C

1 1 1

Dihydro (2,2'-iminodipyridine-N1 ,N ) boron (1+) iodide (1-) (i5.35g,

C.C50 nole) was dissolved in 250 ml of warm 0.05i HClI solution to gi\e

a colorless solution. The solution w.as cooled in an ice-bath to room

1orperature and with vigorous stirring 45 ml of 7'" aO" as slowly

added. The mixture vas cooled in an ice-bath, sucti n filTered, w-,shed

v.ith three 30 ml portions of ice cold water and dried under vacuum over

CaCI2. The bright yellow solid (7.94g, r85. r) melted at 1-:-107.5.

The infrared spectrum in a `r pellet showed absorption at

2540 (broad, structured), 1640 (s), 1560, 1470 (s,broad), 1270 (w),

1210 (w). 130, 1120, 1080 (w), 1065, 1030 w), 92C (.w), 875 (v.w),

775 (s), 730 (,'), and 560 (v.w) cm The proton nmr ,'as run in CH3CN

and showed two mnultiplets of equal intensity at -7.55 ppn and -6.58 ppm

h cm internal e-r -ramethylsi lane. The !IB nmr spectrum was run in CH3CN

rand shcw d a triplet at +5.9 0.6 ppm from borontri I uoride etherate.

The B-H coupling constant was approximately 110 Hz.

The analysis calculated for C 10, NI3 ','as C, 65.62; 1-, 5.51;

N, ?2.96. Found: (i) C, 55.73; H, 5.68; N, 22.C8 and (ii) C, 55.65;

:7. .6; *,. 2. 4

S 1 1 '

I 1-). .-

\ 'Hi

H Br --

H" 'H

~^ I"j3lt-L' yr :k :i c



1 1'

Ie) in 1


( .1 1

;u c i

as a in

n and

f Lumi rT

I li

l u iI

c --I

i I d5

Vhe proc-ct sh...-7ed absorption at 300 (w), 2S 0 (s), 2760 (s), 2460

(s), 240C, 20 (w), 1 50 (s), 1590, 1 0 (), 1 130 14-51 (s), 1370,

1250 (s), 1190 (w), 1170 (w), 1145 (\w), 1040 (w), 9C5, 5-. (w), 600,

775 (s), 750 (w). 600 (v.w), and 540 (v.w) cm The proton nrr was

run in CH3. N with tetramethylsilane as internal reference and showed

two multiple s of intensity ratio 3:1 at -3.12 ppm and -7.44 ppm re-


The analysis calculated for C10Hll --r %was C, 45.50: H,

.23; N, 15.' ; r, 30.27. Found: C, 45.71; H, 4.. ; ", 16.03; Br,

30.10 and C, 45.59; H, 4.31; N, 15. 3; r, 30.29.
Synihesis of dihydro (2,2'-iminodipyridin-N ) boron

(1+) chloride (1-).-


0Hal- -> O^-

H' 'H H 'H

A 50 ml Erlenmeyer flask was charged with a rragnetic stirring bar,

dihydro L(2,2'-iminodipyriidinato)(1-)-N N ] boron (0.915g, 0.005

mole) and 40 ml of methylene chloride ,which had been dried over Molecu-

lar Sieves 3A. Slowly, HCI (obtained from fMatheson) was bubbled Through

the yell ow solution uniii the color disappeared. The colorless solu-

tion was then stirred for five minu-les.

The solution was transferred to a 250 ml beaker and 150 n!

:f Jiethyl ether was added. The beaker was cooled in an ice-bath and

he product (i.02g, '' .5 ) vas suc ion-f i tered, ~ashed with 30 ml di-

eShyl et!-er, and vacuun-dried cover CaCI ,. i solid related at

1 .5-.19 i ih i on.

The infrared specrum of the product sc' absorptions at

30C (w), 2 2 ( ), 1G (s), 1 2,

1 5 (s), 1 5 (s), 1 1575 (a), 1225 :5 ( a d (s)

cn TI e P oton n- r ,as run in nhy

s i I ::n
at -7
at -7

.15. Fcund: C,

' 1 '}

(2, '-i -1 '



F /-\F


125 ml Erlenmeyer fla

dihdro (2,2'-i i ncd

t (1-) (0. 3, 2.75

*Ie ,''.,er ie' ol cu lar Si

Sc) '';3G sa d drcp

;k cona inning a ragne

.rid ine- ) bore

:ole) and 25 ml of n

'/es 3A. iith STirri

c a3rd tIe r-sul I

"ic stirring bar were

n (i+) hexaf uoro-

i rceth-ne which had

no, b- ci e (0.. ',,

,clutc :a trrnd

1 aa ys i
.1 ; I C 1 ^I,

'1 )

PFJ + Br2g >

H/ H

+ other



7 o~

- io 3:1

for four hours. At this time a 1H-nmr was run and there was no start-

ing Iaterial !eft, as evidenced by a complete downfield shift in the

spectrum from the reactants. The excess bronine was destroyed by adding

drop-wise cyclohexane until the solution was decolorized.

The mixture was then transferred to a 300 ml beaker and 200 ml

of dry diethyl ether was added. An off-white solid precipitated and the

mixture was cooled in an ice-bath. The mixture was suction-filtered

and parTially dried by allowing air to pass through The collected pre-

cipitate for a period of about five minutes.

The off-white solid was then dissolved in 100 ml of hot water,

5 ml of 5' NH 4PF6 was added, and the mixture was cooled in an ice-bath.

The white product (0.713g, 71.35) was collected after suction filtra-

tion, washing with 30 ml of ice cold water and three 30 ml portions of

dry ether. The white product melted at 187-188. On subsequent runs

the yield varied from 45' to 75C with no apparent reason.

The infrared spectrum taken in a KBr pellet showed absorp-

tions at 3100 (w, broad), 1655 (s), 1610 (s), 1530 (s), 1495 (s),

1460, 1275, 1265, 1180 (s), 1140 (s, structured), 1040, 1025 (s), 850

(s, broad), 780 (s), and 560 (s) cm The proton nmr was run in

CH-NO2 with internal tetramethylsilane as reference and showed two

multip!ets of equal intensity at -8.48 ppm and -7.67 ppm. The 1113

nmr was run in CH3CN and showed a triplet with extremely small split-

ting at 0.0 ppm from borentrifluoride etherate. The 19F nmr was run

in CH-,CN with triflucroacetic acid as external reference and showed a

double with an intensity ratio of 2.8 at -6.2 ppm wi+h a P-F coupling

constant of 740 Hz and a quartet with an intensity ratio of i at 63.2

ppm with a B-F couple ing constant of about 25 .z.

The analysis ca culated fcr C H9 1
10 9'D

P was C, 32.91; H,

: 3.17; 2. ; N 11.50; F, 41.93.
'-~ ~ ~ ~ I ll, *, !./ ',I I i, U

Synthesis of dif I

[(2,2"-iminr dip ri

H/ H

PF, + NcOH --) IN

F' \F

+ Na -+I PF6 -- H20

Difluoro (2,2'-imi n dipyridi

Sso. .i f i

- 1 1'1
- '3 ) -e (C 1+)

wr and


(v.w i (s), 1 3

(s), 1345 (s), 1. 5 (v.s,

1140 (- d. s 11 (r d.

( ),

, 12 1255 (v.w), 1 1

(s, structured),


(w), a

(w) cl

)20, 1 .-


3 I tetr

d -7.01 ,

The 1 !q1

w'as run k!

rna I hx s

ct pp-. Th*e 9-F .. .ling corn-

C (w) ,

. 5; I, 1 .51; F, 41 .C4

in:c~flc~r r

*'. -

( 1-) (C. 713q, 1.

b id i

r 'cuu

(red. s),


stant ,.-as ca! jlated to be 29.5 Hz.

Tie analysis calculated for iC '."3 w2 C -.1 ; H,

3. , 19. 19. Found: C, 54.51; 3. 1).19.

Syn hesis of fluorohydro (2,2'- irino ipyridine-N1,N1

S( u --- '- -: '- (1-1.--

SI., PF6 -t-,) ^cl I PF6

HI/ \H F/ H

-i- CH -- other products

A 125 ml Erlenmeyer flask was cha-..-' wi+h a nagncetic stirring bar,

dihydro (,2 ir inodip yridine- ) boron (+) hexaflucrophosphate

(1-) (2.57g, 0.010 mole), chlorotriphenylmethane (2. 0.010 mole),

and 25 ml of dry nitromethane which had been stored over M'iolecular

Sieves 3A. The flask was then corked and within three minutes of

stirring, all the solid dissolved and an orange solu-ion resulted.

After twenty hours of stirring, some solid ammornium hexa-

f uorophosphdte (about 1-2g) was added and al lowed 1o mix fo-r ten

minutes. The mixture was then transferred to a .. ml beaker, 400 ml

of diethyl ether was added and the mixture ..s cooled in an ice-bath.

The solid was col elected by suction 1-il --tration and dried.

The impure solid was then dissolved in 100 ml of hot water,

3 :n! of 5, PF solution was added and the solution was -jgain cooled.
Th : .2 c ut (1. -, 4 .7' yield) was col lIcted by suction fi -

-sicn, :. ith tree r "T- S o ie n

C. r Co h

her anJ dried

-7 . 0 th


d r i :


1. F,

. 1;


nv .,r-

0::2 af

I :I

I i
.t 1 beoron.--


ii PF t- NaOH -

+ N a+- P F- + H 20

1 1'
Sluorohydro (2,2 -minodipyridine-N N ) boron (1+) hexaflucrophos-

phate (1-) (1.299, 0.00371 -ole) -was dissolved in 150 mr.l of w.armed

wa;Ter in a 135 ml beaker. The solution .was then placed in an ice-bath

and ccolcd ui-il a very slight turbidity ,,as noticed. With vigorous

stirring 15 ml of Zii N i,- was sloiwly added and a light : Ilc, solid was

for-red. The mixture was cooled to ice temperature, suction filtered,

washed wi h 30 ml of ice cold water and dried under- vacuum over CaCI2.

The lighi yellow product (0.546g, 73.0 yield) melted at 136. At

this point a wass spectrum was run and showed that there was about a 20;
1 1'
imrpurity of difluoro [(2,2 imirnodipyridinato) 1-)-iN ,N ] born. At-

terpts were made to sublime the desired product from the ;mpurity but

were for the mrnst part unsuccessful. Elution chrorratography proved more

succes-fu I .

A column 2.2 cm wiJe was packed with neutral activated alu-

mina (60g) and Ig of the ;rpfre product ,las place crn he column with

5 ; I of me-hyiene chloride. The column was then developed with approxi-

maTely one gi Ion of benzene and finally cleared with 500 mi of methyl-

one -

f raci

A ir

i n c i o



1 25
1 1

ru n

he firs four

WOU7 1 I .

or e. here here fcrty-i-e T:acTicns in1 a1l. T

S; Q S .. ..-r r 'sun 5rnd 1Ot 0n I a 1C, Pi; '; '

aD I
)Gipyrici : o)( i-)~ o ..I "s .i i 1 l

. ( s : ( K . a.). I -"O I 1 11.

, 1 (

C I .

, 7- '

t i lu r. (1:1). --


+ BF OE+ -->
3 2-

1r OEi'

, 11

( : ,

rt H




A 123 ml Erl3nme,;er flask w.-as charged with dihydro [(2,2'-;minodi-

pyridinaTo)(1-)-N1 ,N 1 borcn (4.58g, 0.C2 mole) and taken into an

irnar atmosphere chamber. The solid was disso ved in 40 ml of dry

ethylene chloride to give a yellow solution. Slowly, with stirring,

boron trifiuoride etherate (3.30 ml, 0. i :) nole) was added and the

solution was decolorized and became warm. Af.er about five minutes a

few while crystals could be noticed and within ten minutes there was a

large quantity of small white crystals in the reaction mixture. The

crystals were suction-filtered, but because they were very fine, a

portion passed through the filter paper and the filtrate had to be

filtered again. The white crystals were then washed with three 30 ml

portions of diethyl ether and dried under vacuum.

The fine white crystals (2.65g, 42.45 yield) softened at

100; at 191 they started to yellow and by 19:' were a red-brown

slush but did not completely melt. The infrared spectrum showed ab-

sorptions at 3120 (w), 2480, 2395, 2350 (w), 1620 (s), 1585 (s), 1475

(s), 1450 (s), 1360 (s), 1290, 1260 (s), 1175 (s), i155, 1110 (s,

broad, structured), 1080 (s), 1050, 1000 (s), 895 (s), EDi (s), 785

(s), 745 (w), 635, 610 (w), 500 (w), 430 (w), and 400 (w) cm 1. The

proton nmr was run in CH3CN with internal teiramethylsilane as internal

reference and showed a complex multiple centered at -7.70 ppm. The

mui.lt ip!et was 66 Hz wide. The 1F nmir was run in CH CN with hexa-

f! uorojenzene as internal reference and shcied a clean quartet at

-20.60 ppm; the B-F coupling constant was 16.5 Hz.

The analysis calculated tor C10.-, 0N32F was C, 47.68; H,

4.02; N, 16.76; B, 8.62; F, 22.72. Found: C, 47.75; H, 3.87; N, 16.50;

B; 8.95; F, 22.44.

Syri -Csis of diflucro [(?,2'-ir ino d i id na o) (1-)-' ]

Sor-cn crcn tri fl uori (1:1).--

.NI I ._+ F3 OE E+2

F' "F

+ OE+2

A 25 I Ecr--- r fl~sk

pyri dina )(1-)- ,1 ]

an inr? s rc-spere chase

:-'e l,yl,.e c :loride to 9i

tcrcn r ti1lucrid e '': 'erd

f r s i

Si ght

Si -h d



an (. .O~-1 :ie) a

i d v;a. d
o I ,Jt i .

)r W

lcw solid -ecipiia ed cui of solution.

-, as uc ion-fi I rd i

id Ji der vacuum.

1 1'
An altern e ee preIar c of

1p:a di aro) (1-)- ,N ] bcro boron t-if'uo

b ron trifluoride with difluoro [(2,2'-iini

n boro on 1he vacuum line. A .. ml rc nd-bor

i uo o [ (2,2 '-ini dipyridi n o) ( -)-_ I ]

), a netic s irri bar and The flask v>

i n

in 5 l1 dry
4in into

s., i h i i nc,

addcd d -wise

iueS r re-

s :dd sd a

ye l sol i

of di-ehyl ether

if oro [(2,2'-

ie (1:1) was by

id ipyrid ina io) ( 1-)-

m tak was charged

oron (2. 9g,

Spla ced.n a high

s har with iflu or [(2,2'-imin di-

AfTer evacuation, 40 ml of dry n'thylene chloride was trans-

ferred ,o the reaction vessel and 'Ihe soii did dissolved ith stirring

give a yel low solution. The solution was cooled to liquid nitrogen

temperature and boron trifluoride (obtained from 'atheson, 0.0104

mole) wias condensed on the frozen solution. The solid was al lowed to

warm and the solution vwas stirred. As the reaction proceeded a light

yellow solid precipitated. After twenty minutes of reaction, while

slovly airingng, all the mothy!ene chloride and the slight excess of

boron trifluoride was removed. The solid was dried under vacuum for

eight hours. The light yellow solid softened and star ed to darken

around 1 a' and melted wiih deccrpos iion around 1910. The infrared

spectrum of the product shceed absorprions at 31C00 (w), _70 (w),

S (w), 26:-- (w), 1660 (s), 1630, 1610, 1530 (s), i4E5 (s, brad,

structured), 1460, 1_ 5 (brcad, structured), 1275, 1265, 11.: (brcad,

structured), 1130 (s, broad, structured), 1090 (s), (s), 910 (w),

870, 7', 640 (iw), and 535 (w, broad) cm-. The protcn rmr spec-

trum was run in CH3NO !Owith internal tetramethylsilane as reference

and showed a complex multiple at --1.90 ppm, 70 Hz wide. The 19F nmr

spectrum ,,3as run in CH3CN with hexafluorobenzene as internal reference

and showed two quartets of area ratio of 3:2.1 at -21.6 ppm and -10.3

ppm respectively. The B-F coupling for the quarter at -2i,6 ppm was

15.1 Hz and the B-F coupling constant for the quarte- at -i0.3 ppm was

23.7 Hz.

The analysis calculated for C H8MNN3 2F5 was C, 41.87; H, 2.81;

N, 14.65; B, 7.54; F, 33.12. Found: C, 41.64; H, 2.78; N, 14.-3; B,

.60; F, 33.34.

Sy -h sis cf di !-p 7 7-)'-(n irm 1 n,--^ ,11 n1


+ CH, I PF6+ -

H" "H

,, t

* 1 (1 10

1 i
-hi ,4

I i ( .2 )

ml of

of di-

. 1 ,

A 12 i r

Fi :> e)


IX i ;\ U i

90.t, ) rreli d at 213.5-215.50 with de -:-itio". The infrared spec-

tr-ur of ie prcduct showed absorpTions at 31-D (,;), .l4-4, 2L4 :. .7?

125 (s), 1 .. (s), 1570 (), 1 3 (s, broad, strucTured), 1370 (s),

12 1210, 113110, IC (w), i. ) (w), 840 (s, broad, struc-
turned 560 (s), and 425 (w) cm Ie proton nmr ;:as run in C T'

with internal! tetramethylsilane as reference and showed a singlet at

-3.73 ppm and rio complex multipleTs at -7.52 ppm and -8.34 ppm. The

rultiplet at -.4 was 22 Hz wide. intensity ratics agreed well

with the expected 3: :4 (singlet:u I iple :iultipler).

The analysis calcula ed for C1 H P ;as C, ..51; H,
11 1- 6 6
.83; N, 12.25. Found: C, 3 ,21; H, 3.75; N, 12.13.

Synthesis of hydro (4-picol ine)(2,2'-irinodipyridine- l, )

born (2) fexafluor olospiate.--

I'B -+ ( CCIO4

S''H CH,




'-.a:N -,z2 PF


-I other

l ,n-e,r fla-k .as chr.id in he cr box ., i- 1 a :raogetic

1, 1'

,. ole), -ri eth perch (1.59C, C.A T

S, acatcn r i e. .pn diio of "he solvent.

SII -; c.w I ii "io'n Kh; a ah ; ai Ac id reS I aed .

S( :) 1 i I1

, 12 1 ( ), 11 11

), 1

i, 1

(C ),


S( )

as in


A i25 r:



T i
,'h ('

-i i^

(C ,

1 ; 0 i

which was 87 Hz wide and a singlet at -2.63 ppm. The intensity ratio

agreed well with the theoretical.

The analysis calculated for C16H17N4BF6P was C, 33.95; H,

3.03; N, 9.90. Found: C, 33.87; H, 3.23; N, 10.02.

Synthesis of 2,2'-dipyridy lar-noniur (1+) iodide.--


DPA +- HO +-I --> IL I + H 0

Although non-stoichiometric quantities were used, the desired product

.ws obtained. To a warmed solution of 2,2'-dipyridylanine in 2M HHNO

was added a concentrated NH41 solution. A gray precipitate immediately

formed. The mixture was cooled in an ice-bath and the precipitate was

collected by suction filtration. The gray solid was dissolved in

warm water, filtered and the filtrate cooled in an ice-bath. A white

precipitate formed. The product was collected by suction filtration

and dried under vacuum over CaSO4. The white solid darkened when ex-

posed to air. The product melted at 2170 with decomposition.

The analysis calculated for C1 H 11 I was C, 40.02; H, 3.69;

N, 14.00. Found: C, 39.49; H, 3.39; N, 13.65 and C, 39.40; H, 3.37;

N, 15.33.

'r ,


-+ XsNaBH ---

H13 B BH3

+ other products

In ani in

cha r *;,

a ian

ic I ecu lar

pered. r<.

for an a.

irg Te r

nd re

s rU"--- ;

Cs), 155

i120 (;),

5-.I C:-= >




h 2,2'



A. r" {"

lb r, a

- i

3 '' r, I
2 n-

icr"., d- L f a .01 as
icdi ( < .2 ;a. 0.01


o ir u il i

r- ide (1.51 O.

;.o\ ed from the d c

d i ion~l I hours.

The of f-;h lie prodc

-ec icn mixture vw'ih

ri The w.ih ite soli d

d sharply at 1. .5-I1

of the product shed

Sand from 2310-2 ,

(s) 1. 12 (w),

i (w) 1 (v;) ,

v,) cm Tha proton n

.d ium b

Iask :,'a

.i. lg, 5

03 ml of '

with ec

bscrpT in

1 0, i

12 (w),

5 (.':;,

:r spec-r


d over

n as

i he

s stop-

s i rred

S) IwIas col ic !ed after mix-

0, co :ng in an ice-bath,

dried under i*cEuJm over CaC12

i icn. e infrared

ST 40, a very broad

3 (s o r), 1. ( ), 15 ;

S(w), 1 O (w) 1 ,

3 (w), 950 ('w), (w),

rm '. s taken in Ci 3C; .i th in-

eternal tetramethylsi lane as reference and showed a highly complex set

cf peaks which could not be interpreted. There was a structured triplet

at -7.16 ppm, a broad structured singlet at -7.62 ppm. a three-peaked,

highly structured multiple at -8.01 ppm, a broad structured double at

*-8.50 ppm and a very broad singlet which was approximately 30 Hz wide

at -9.47 ppm.

The analysis calculated for C H 15N 342 was C, 60.39; H, 7.60;

N, 21.13. Found: C, 60.35; H, 7.62; N, 21.24.

Synthesis of 2,2'-dipyridylmethylammonium (1+) hexafluoro-

Dhosnhata salt.--

H 30F + r-
S-- Br2 > N PF
H 3 H

-+ other products

A 50 mi Erlenmeyer flask was charged with dihydro [(2,2'-(rethylimino)
1 1'
dipyridine-N1 N ] boron (1+) iodide (1--) (1.62g, 0.00500 mole), a

stirring bar and 25 ml of dry CH3NO2. With vigorous stirring, bromine

was almost immediately decolorized until the last drop or so of bromine

was added and then a brown solid formed and the solution remained amber


After stirring the reaction mixture for ten hours, the mix-

ture -.as placed in a 500 n! beaker and 200 ml of dietnyl ether was

added to precipitate an amber solid. The mixture was then filtered and

partia!!y dried by let-ing air pass over the solid. To the colid were

added 5; ml of 4 I, : ml cf of- ,.'a er and 10 ':r of 0. 1; Na SO

(The 0. K; T'- 'O 3 was used o dsti a ir~ rce icn or any rixed

triha ide icn which h had ored.) 'ih iadd iO of he slui on,

the arber solution .s decolorized -o a l Ii i ei lIc. To the hot

solution was nov added 5 ml of '' an te sou cooled in an

ice-a- h U c ol ing, a fine hie -e i i e fcr d. ie

solia ( g, 4 as fi : . s i 0 io s

of diethy e er an dried u '.CJUr 3 e s l

rn- I -re 1 74-1


ie I

water in a

The in frr

broad), 16.

131 ) (
1310 ( ),

(s, bra ,

The pro o

ro ferc:

and to

3.65; 1

3.77; N, 1

5 (s), 15:0, 1

( '), 11 (C ), 11

cfjred), 5, ,

1-0, 1

), 1


nd sheoicd a si I:

p I ex Ultiplel s at

io of four.

analysis calcu

.68. Found: C,




31 (w,

1 (w),


, 840
(s) crmn

4- io throe

,;0i h an in.

': H,

39.95; H,

S11" 1 '. 6-

.65; ', 12.

-- tL

" RI

,11 CH3
3 3

!,I + NaOH --> + No + H20
-~ ,\ :]1~


*-) ,

., ,

2,2'-dipy- i dy Iethylarrmonium ( 1+) hexafluorophosphate (C.5COg, 0.00151

mole) was placed into a 60 ml separatory funnel along with 25 ml of

water and 5 inl of 2!M NaOH. The free amine was then exIracted with five

25 ml portions of diethyl ether and the etheral solution was dried over

3g of anhydrous Na2CO3. The ether was removed under vacuum and the

slightly yel low-colored liquid amine (0.173g, 62)) was pumped on for 24

hours over CaCI2.

A rrass spectrum was run at this point and no peaks occurred

above 186 mass units and the majority of the fragments could be accounted

for. The product boiled at approximately 240.

The infrared spectrum of the product taken neat between KBr

plates showed absorptions at 3060, 3010, 2160 bradad, 1585 (s, broad),

1470 (s, broad), 1425 (s, broad), 1355 (s), 1330 (s), 1280 (s), 1140

(s, broad), 1080, 1055, 985 (s), 695, 775 (s), 740 (s), 640 (w), 620

(w, broad), 570, 530, and 410 cm-1. The proton nmr was run in DCC!

with internal tetramethylsilane as reference and showed two very com-

plex nulfiplets and a singlet; one multiple at -6.30 ppm of intensity

ratio six, the other multiple at -8.26 ppm of intensity ratio two, and

the singlet at -3.82 ppm of in-ensity ratio three.

The analysis calculated for CI H11N3 was C, 71.33; H, 5.99;

N, 22.68. Found: C, 71.24; H, 6.09; N, 22.80.

Structure Proof

Structure proof of dihydro F(2.2'-iminodipvridinato)(1-)-
, 1 1 '
_N N boron.--It was noticed that the proton nmr spectrum of dihydro

2,2'-irminodipyridine-N1 1 ) boron (1+) iod;de (1-) and that of the

corrospcndring hexafluorophosphate sal-t had -*wo multiplets in the aro-

malic rccicn .-,hich aere of different i nt nsity

had a rul-iplet inotnsity ratio of 3:1 ard the

had a :r: Iliplet intensity r tio of 1:1.

salts (i.e., chl ride and brc i de) were ve-y s

icdide salts a a lso ad to tuip lets in h

Gsucneste SCT"'^ sort of 0CIC-: i. "i ~ io'n : +"ee7n 1

ra-ios. The iodide salt

hox icre hae salt

So h other halide

ri lar o that of tne

Sra io of 3:1. is

h< i :d: iC, lnnd the

SA ,


:hree ( *s o

sli ghI I ye Il'

fcerred, so

solution As ru
STc -oC

i pi- ate

e &ow

3 l~n

c-ic ar ion tnrO' an an'

nn- trum.) rt

oton as evid :iced

Eveiua I ly it ,.as

r ccuc be converted

,e and fi ITering off

r3 lI ed %ell1 or C '

i le .

: brane producs a do;nfie!d shift in t

Skya 1rines .sre ied also re-

Sa dcnfied -hi f if their pro on nmr

;und hat hs iodide s l" in n .. eous

0 The l"neura adduc ading sodium

bri 'I 1 w solid. e yel Ic ccTm-

; ticn ow arose--from e

e are 'I.o tauter, rs, A and w, both of

equa I



cat ic n



h, r -

0h i c

at or





Tautomer A would be a trigonal born in a hetGrocyclic system that was

stable in air and aqueous sodium hydroxide and tautomer 3 would be a

stable amide zwitterion. The infrared spectrum of this "neutral" com-

pound was taken and the 2300-2500 cm- region showed a highly struc-

tured band at 2350 cm-. This was in the region where amine borane

B-H stretching occurred but the observed band was of no structural

help. In the infrared spectrum of the cation the i-H stretch was not

easily discernible and therefore could not be used in the structure

proof. Tautomer A was eliminated on the basis of the following evi-


If the "neutral" compound was reacted with DCI, the infrared

spectrum in the 2300-2500 cm- region looked exactly like that of the

HCI adduct. There were three peaks corresponding to a BH2 cation.

The H-N and D-N stretches could not be identified.

The neutral compound was allowed to react with methyl iodide

and a cation was isolated which contained a methy! group. In the B-I

stretching region of its infrared spectrum, there could be found three

peaks charcrrTristic to a cationic BH2 group.

Fi;nlly, the 11 nmr was run and a clean triplet was ob-

1 1'

1 1-l`

(j C

I" I
i C;j

;/~`S- ;~.?il rPr 3 ~ic;S



i I c r

i I T i

,'as recoereu in a subsantial nt s -'- as a. i eced b -ie proton r.r of

-h produc-,

r, i r .

Diflucrination of dihydro (2,2'-iminodi.. .ridine-N N

.' .1. ' -.l_ . . .-- In the preparation of difluoro (?,2'-

1 1'
imi non ipyr i d i n- ) boron ( +) hexa Iuorophosphate (1-) -here are a

n.Gorl of possibilities which could describe he reaction pa hvsay. Does

broMii na ion occur first and then halide excr ...; to produce a T ioriared

product, or d ,es fluorination occur first and the brc;ine on prcduce

the Iluorinatir a '? Several reactions ere carried cu to as..or

this question.

It was noticed that during the reaction of bro ie ith i-
1 I I'
h' :ro (2,2'-inirno ipyricine-_ ) boron (1+) hexafl ucrc hi pha e (1-),

th! bromne ''as i'di t ly lorizd, az n acidic gas appie; e

the solution, and the glass reaci ion vessel ..as etched. 1hen he bro-

mine reac-ied, the first step would produce a species and an -

r olec:ule vould be formed.

S. N N
I, i -t HLr

H' H Br

The H r cou d then either react with a r--H cind/or The hexafluorcphos-



I- +- H Br -- II Hi
-. ,N/N

H H Br H


>,N- ,-N NY -N
I | + H Br ---> A + H2

8 8
H EBr Br Br

H Br + P F -- -> IPF3" 4- 8 r

It hbs br`en Cow nstrated b Geb ild ndr Jones (40) that in strongly

acidic jeus solutions a kali h flI o h. tes h rolyze via a

H,0', 6 intermediate ich thn c ,s ino n5 ad F s ins.

!f irt s of j ater in the solcnt ..r re n rovd, a ccies such as

HO 6 cc: ssibil initiate the fu -riatii n r:c on (1) ). Al-

hough ot uc is known abu he reaction r echanis, there is aiso

a cls of reactions knSown s S:rts reactions which use and anti-

Tafluoride to hal -te a variety of substances (42). A

si .1 f lu rina i a ent is S F and h re e, it would

net nreasonable for the and 6 o ct as the fluori-
natin it b forming which then d roses t HF and PF5.

i -, ,, i a 'y o cget her, IF and could be he ac i ual fluori-

nalting agent.

find oui if brcminaticn of a 3-H bend .'as neccsar',, -he

following TWo experiments were carried out.

Experirenrt A.--A 50 ml Erl i :r flask was charged with a

magnetic stirring bar, dihydro (2,2'- iinodipyridine-!il Q ') boron (1+)

bromide (1-) and 30 ml o, dry CHl .0 Because not all -he bromide

salt dissolved, bromine (0.27 ml, 5 rmole) was added to the slurry drop-

wise with si irring. Almost immediately, the br mine was decolorized

until the last drop was added and a ellcw solution result ed. The

solution was stirred for cn minutes and became co! less ii h a

'white soliu suspended in it. Solid armoniur haexailuorphosphate

(about 2g) was added and -he mixture was stirred for- ive hours. At

this tire, he reaction mixture was placed into a large bea ker and 300

ml of Jry aiethyl ether was added to precipit te an orange sol id. The

beaker was cooled in an ice- ith, the so id as sucti ir-fi Itered, and

partially dried by allowing air to pass over tie solid. The product

,qas dissolved in 100 ml of warm water, filtered and 5 ml of 5.' NH ; PF6

was added to the solution. The solution was cooled in an ice-bath and

an of -w-hi e solid (0.737g, 41 I) ,.,as collected by suction filtration

and dried under vacuum over CaSO4. The off-white pr-duct melted at

152 and was identified by its infrared spectrum and proton nmr spec-

trun as difluoro (2,2'-irrinedipyridine--N ) bcron f1+) hexafluro-


Experiment B.--A 125 ml Erlenmeycr flask was charged with a

magnetic stirring bar, dihydro (2,2'-iminod ipyridine--N ,N boron (1+)

ihxafluo-ophcspbte (1-) (2.83g, 1 mmole) and 70 ml of dr/ CH3N02.

Hyd jo.C.l. bromide, which was purified by passing it -i-hi-ough a 1-rap

er F inT

i ?Fr

1 1'

r : I i :; I'

'- i 1'

si i i usir,

-aS, a svnthii,'tic

;cc Id i a -.e7-'-, lcyclOhex rne sl-sh, ..13 lub3lcd in-

1ss Tie fivot i

O- ,:3 CqI

+,:n r i

, fi l-

I..- ,. I


i o Of

dihydro bis-4-picoline boronium (1+) hexafluorophosphate with bromine

was studied.

A 50 ml Ericnmeyer flask was charged with a magnetic stir-

ring bar, bis-(4-picoline) boronium hexafluorophosphate (2.06g, 6 mrmole)

and 25 i! of dry CH NO2. A bromine solution (1.23g, 6 mmole in 10 ml

CH NO2) was prepared.

Into an nmr tube were placed 50 drops of the bis-(4-picoline)

boronium hexafluorophosphate solution and 20 drops of the bromine

solution. The proton nmr of the resulting solution '..as run at 1, 5,

10, 15, 50, 240 and 600 min. The re dining portions of the reaction

solutions were mixed, stoppered and allowed to react.

The reaction mixture in the flask went from amber to light

orange within five minutes and was allowed to react for four hours.

At the end of four hours, cyclchexene was added dropwise to destroy

any brcmine which remr ined in the solution and the solution became

colorless. The reaction mixture was transferred to a 600 ml beaker

and 400 ml of diethyl ether was added. Only a small amount of pre-

cipitate was obtained. After filtration, an aqueous work-up with

ammonium hexafluorophosphate was attempted but nothing was recovered.

The nmr tube portion of the reaction showed that bromina-

ticn occurred within one minute as evidenced by a downfield shift of

the ring protons. No further changes occurred in the spectrum after

10 hours, although some material started to fall out of solution.

At the same time, the reaction of bromine with dihydro

(2,2' irrnodipyridine-N N ) boron l(+) hexafluorophosphate was run

on a large scale and in an nmr tube with the reactants in the same

concentration as ihe previous experiment. As evidenced by a downfield

15 *i


1 1 '

1 1 '

1 1'

in ni r sp ctr

are" i r,2" i CxI re'i i1"c

i d i; a 0o)

After 44.0 ml (5.09 rm9oles) i-as added, the solvent ,as rero'ed under

'va.cuum and the li '.'- il lowI sclid was takeH into lhe cr; cox. The

solid melted in a sealed capillary aT 2;.-" with dec -os- ition. he

product '.as not soluble enough in methyl!ne chloride, acetonitri le

or nitromehane to give a usable proion nmr. The infrared spectrum

did not show any B-H, stretching vibrations. A s nl I portion was ex-

posed ro tne atmosphere and appeared io rapidly hydrolyze. i 't

yell cw solid decomposed in the dry-bcx to a lig green material.

The analysis on the iigh- yel low mratorial calculated for

C10, .." _-r2 v as C, 35.03; H, 2.94; N, 12.26; and Br, 46. Fc. nd

C, 31.71; H, ;; N, 11.93; and 3r, -,.78.

Experiment 3.--A 50 mi Erlenmyer flask vas charged 'with a

r.tqgnetic stirring bar, dihydro (2,2'-iindidi. ridie- 1, bocn

(i+) br-cmide (1-) (i.32g, 5 nrole) and 25 ml of dry CH 0,.2 To the

sl irring slurry vwas added br-ocine (3.0 rl, 14.5 rr.ole), drop by drop.

Up until about 0.30 ml was added, the solution turned amber and a

white precipitate formed. \I'ith the addition of all he bromine, the

reaction mixture became a clear armber solution. After stirring for

18 howirs while stoppered, cyclohexene was added to destroy any excess

bromine and an orange oil and a white precipitate dropped out of

solution. The reaction mixture was placed in a -:.. mi beaker and 300

ml of dielhyl ether was added to precipitate out an off-white solid.

The mixture was suction-fi ltered and partially dried by briefly allow-

ing air to pass over the solid. The oil and white solid were then

dissolved in 40 m! of water and a green, acidic solution resulted. To

the noiuiion was added 4 ml of 5M N!4PF6 and an off-white solid pre-

cipha--eu. Ihe mixture was cooled in an ice-bath, fi altered, and dried

unde-r p acuur ovr CaSO4.

and :'ac identi iied

spc-r3a of en authentic

f I oropcsphat e.

i 1'

ir i nod id r i ine-i I ,e -

hvdri 'e abstracticn Frc-

bcron *.*;i':h tripher

I ir and fi all y

occur so rcily,

proc of r o in

11 1 'I bo n.

The vahiTe solid (C.523-) rseied at 191-1940

-ri its infrared ard nr- ec-tra to the

le as 2,2'-dipyr i i oniu (1+) hexa-

.-- (-picoline) (2,2'-

.rorn (2+-) h x-3flu, :':cs 'a e '.as prepared by
u d 3 by

i dro ([ ,2'-iri :di .,ri. :ii; c)( I-)-' l, ]

p rc r I .ro re, s.l' j.jn a di? icn 3f r-pico-

, s ,rk- up. Since uro-iration 'eared to

s ,;re rCi'e to d I ,Ce ine f cor; ',he

r iact n i

'- .i

r; .--A i

c stirring ar, dihdr

1. ., 10 e) a 6

, brmine (0. m 1

S. The br- ine was ii

tated lrc solution.

color persisted. Aft

1, 2D nole) was s lo

so ution r esu ted. In

Reaction mixture w

: off awilh a after a,

crystal were diss

of 4 had een

iion \;as all oved to c

,,as ol ;ctfed by suct

s car iith a

i r ul ing

iso nd i ith
iIe a white solid

*rely d

addi i

Srri '


i ra



d d. A I the

ut fve r nute

stirred o-ernig

or to I fcive so

d in i IT l of

, 5 l of

in an ice-bath

fi I;-ra ion and




ot wV-i

4 6

A br

r i ed

S, the

c-S, .-picol ine

issolveI e and an

o I i d b r to

the solvernt- was

a crystals be-

ter- o which

'as added and

c-,rn pr ec pita-te

l di r vacuuI.



s f i r r i n


brom i n

( 19.2 ,

(1C :1

stri ppn


thr ccr

i e si

(2.2: )

cover CaSO4. The brown solid wias identified as the amronium salt 2,2'-

dipyridylami e with a mixture of tribromide and hexaflucrophosphate

as tlhe counter ions.

Experiment B.--A 125 ml Erlenmeyer flask was charged with a
1 1'
magnetic stirring bar, dihydro [(2,2' -iminodipyridinato)(1-)-N ,N ]

boron (1.83g, 10 mmolo) and 70 ml of dry 4-picoline. The solution was

stirred and bromine (0.55 ml, 10 mole) was slowly added. The first

0.44 ml of bromine was immediately decolorized but further addition

of bromine resulted in an orange-colored solution which darkened

rapidly io amber. The reaction mixture was allowed to stir for 36

hours and a light brown solution with a light brown solid in it re-

sulted. The reaction mixture was poured into a 600 ml beaker and

about 150 ml of water was added. Vigorous gas evolution resulted.

The solution was neutralized with 4M HCI, 10 ml of 5M N!i4PF6 was

added, and the solution was cooled in an ice-bath. No precipitate

formed, and an additional 2g of solid NH4PF6 was added. If hydro

(4-picoline)(2,2'-iminodipyridine-NN 1 ) boron (2+) hexafluorophos-

phate had been present, a precipitate should have been formed at this


Exneriment C.--A 125 ml Erlenmeyer flask was charged with a

magnetic stirring bar, dihydro (2,2'-iminodipyridine-N Nl ) boron

(1) hexafluorophosphate (3.29g, 10mmole) and 70 ml of dry 4-picoline.

To the resulting slightly turbid solution was added bromine (0.55 ml,

10 molele. The first 0.44 ml of bromine was immediately decolorized

ti- the last portion gave the solution a very dark amber color. The

solution was stirred for 60 hour: and a small amount of dark solid

focm:d. The reaction mixture was placed into a 600 ml beaker and 20 ml

.iClrcus s I jlicn re'-, ed d I d prc- c co uld

. i '.h a

I -I ." ", *

1 I'2



1- ) .' ,"

:'+ hut~ no

- i i ne.

Is a e d .I '-, 4-

Ir n.

ji -o r~(2 2'1-

, c(1na-o ( -)- 1, 1' ]

*-~ ..

i pyri

- h ( i k. i

c:f "`.~ ..~-3S ~odc~

p c ; i

Exarii -ent A.--A 300 ml three-neckec roiond-lbotomed flask

Tic stirri

2'-inr no ip ridi nat )( 1-)-N I ,N ( 10I

hydride (1.21g, 32 rmcle), and 100 ml of dry inont

removea from the dry-box and under a ni -ogen a-ro r

oqu: -pressure (dr-Yping unnel ;.as set into place, .

tin (1,27g, 11 mmole in 50 ml of dry monog!yme) ,

dropping funnel. Slowly with vigorous stirring th

wss added over a period of 60 riru es. The icdie

and hydrogen was evolved. After all Che iodine vi,

gly ine as bloa;in off with nitro en and ne el low s

for i-enty-four hours with a afterr aspirator. The




in the dr

ex+racted with

1.3 ml of irothylnc chloride.

Af er the re:'-ylene

ch!ccide was r moved, a yel clw solid (1.79g) re ined. 1he product

Sel-ed ai 91.5-9. The analysis calculated for C10 was C

61.02; H, 65.5; N, 21.35; 3, 10.3. Found: C, 55.24, 55.47; i, 6.79,

6.93; N, 18.51, 18.89; B, 9.92, 10.03.

Ar -empts to purify the product by recrystalli izatio and

sublimation were to no avail.

Experiment B.--i a high vacuum line freshly prepared and

purified diborane (4 mmoie'i was condensed on an etheral solution of

dihydro [(2,2'-iminodipyridi naTo) (1-)-N 1,N' ] boron (0.534g, 1.62

minmoe in 30 ml of dry diethyl ether-). rhe frozen reaction mixture

was al lowed to warm up with stirring for twenty minutes and then was

frozen wilh liquid nitrogen. The solution was a lowed to warm to -77.

The e-emperatLre was kept constant by submergi '3 the reaction vessel

in C-acuone balh. The reaciiorn mixturi- was stirred for 40 minutes

box i th a r

bar, dih' :'ro C(2,

-ole), sodium boro

me. The flask was

here a 125 ml

An io ine solu-

added to ihe

iodine so ution

e c'- od i r; ed ia i.- I y

added the r onc-

id was pumped on

.llc, solid .ss


ure. rhe s

.; sol id, v:a


Sadd i ficnaI

to "1- 1 -a

c I vyen

es v'ei

ar 'n i ,

very I i

2. .

I-) -iA '

sk ";3s

re [(2,2'-

1:1) (0.

Six ure

i l 1i id

ii I b, 4. 19

rczon ietily-

uii d uin

0 rniiits ar

*,;s V1en core

.Dr 3C minutes

*r n; no nc

nd conrdcsed

ad been rem-ol
reac on

sou ion was

2.3 nr..o of

ed and

ise I a

ti t rat

I ,;c-i ;

I had re

id o1n for

.ith I
cco" red. T

;d dr- i


vas reoved and the product, a

d under cuum fr 16 hours at rc-rr

Loss. e ad '(d eightt (0.0 ,

Isr 7o /e ti-e d:'ircd -oduc-t.

"d si r.i.e :chloride as u he

- ,

1 1'

1 of th

hic-h :cu


s Ii (


li j i

1:3-1 i

, and was

dense with

'the tota I

Ssolu i i

an add i

I si

n. AfT

h the

i ra I 1


jd ard

-e then

;r a l Thc


I blue

Cfo;-ro niir

Ie i

ir idI


I lac

ec r'a =I:c''ed tat some chances had taken place. l-s ,j o 7 a large

/ery complex I ul-iplet centered at -7.70 I pro -._r rnr showed

"wo rultiplets of intensity ratio 1:1; cne at --7.3 pp: and the other

a --.,2 ppm fror internal I etramethy I s i I e. The infrared spectrum

shc,,ed additional peaks which could have ee I in (44).

Because of the addition of -'I o dih 'ro F(2,2'-iminodi-
1 1'
pyri c inato)(1 -)- 1_ ] boron boron trifluoride, an a rTeirp' v.as made

io de ermrine if boron tr-ifl, ride could add ao dih',dro {2,2'-ir-'irodi-

pyridine-N .,1 ) b:ron (1+) chloride (1-). Ali h .i native, he

foil ing expori -ent was of reat \a lue. A 50 ml ilask ,as c ar -

with dihydro (2, imi nodipyrid ine-i ) bcron (1+) c oI ride (1-

placed on a higt- vacuumrr line, and evacua ed. Excess born tri-

flucride was -chen condersed on the sol id ',ih liquid ni ro ren and

then al loi ed to arm up. This ''as repeated tn timis and then all

t-e bron 'ri fluride was re .ved. The infrared and proon nmr spec-

tra e;re run and ,.ere almost identical to that of the product cf di-

hyro (2,2'-imincdipyrdiinao)(i-)-1 ,1 ] boron boron tri luoride

(1:1) and HCI.

-7 IV

`- -, Iv '--

1r (:- (2,4-

1-) -

I 1


~lrclrciz ~r

G3-58, rii$iu

S\ \.

W -AVEL (n)
b/ \ c o.
/ \ /
0 \ \

I /I

\\ 1\

vVA/.VELf.J G i (nm)
i i

FAbso binc species = 4.62 A 10-5
[Aibsoi binu; soecie.3'1 --- 4.62 A: 10




ji I 0.

/I L

(1 / 0 1 N
/ F I
SI I J.,

( I / I \ 0.2
I .3

ri i
/' f, 1 ,
i / I -
/ i >

I_ __. I _,.-L ,,,.

I 1 -C

S, 1 N ,N oJ

F h~rin CF"ci(3]1)















0.2 c

0. I




E!ec ronic spectra of fluorrohydro (2,2'-iminodipyridine-
.', ) Lboron ( 1) chloride and its conjugate base.

[Absorb: g species] = 4.57 X 10-5


Figure 3.

(1m )

-as psible, by ca-ef lly r-nitcriin the p' of the solution, to deter-

mine ie K of The acid-bae conjua-e i s s pc t rical y.

Usin th ehod desc ibe Deush a Jbe (35). and by

assuming tha as the pH is I eered Ie ur -ocnated form is converted

to ed form, the 'olc in rel a i ship lies


, -I i
, c- i

c' 1 I + I


Si on:


c ien'



rn and 6

.of the *

, not affected by he absorp i

re c ranc ittance fal l in

*ence be tv.en the co ieteli

ris u d in h e calcu l- ti

'M-d cSicns ,3as checked :vi

ej: ued scale.

king thei

S ere the acid and base f

tca of those so utions ;h

uni t .'i -hi7n ihis range vere

:u 1,d in c ion coeffici en s

y those pH'

ttal dif-

-o onusind

the buf-

"eter using

is ,,ere in

kea a ins

were caIcul.

Src o 9, the pH

jii t i. .5s -ound. t

j approxi e I y .15 of a

a ousfer Isolutio refer-

i+ed. From he extinction
























N NM f in u3




I! -
b1 I





o -









0 -1

3 )






(- X


0 1-




















- N NM .4 Ln r'

0 o0 0

1 o N o O C r-> i
[ C C N -I t~ ^

0 NC 0 (D- '-
0 N 0 CO cO 0 Vq NM

0 0 c O




o r-- m m ( tj- ^ v--,

0 0 0 0 0 0 0 0 0 0 t


o LnL 0 10 0 [
0- 0 [0 n 't 0 t
12Th 0- 0 N0 I M O N 0'
k- 0o LC O t t 5 t 1T -

coefficients and the pH I-f

csncentrdaien of the absor

data o gained nd the calc'

solutions, 'he K was obtained. The

,ccies, the 0a',,el Th ircnitored, the

ill s n
yo.re oR il taken in *- Ileis on a

Aprid: i? r i -iI .t-,ic^ *.*as -k en ne' tO


f wi th

ran iP-l;

thuj ircit

usea Ior

:7 cm

r -

ST ruci u (

, for t

0 cm-I1 r;

r s i

hk --I

: :ore .. I ica ed -

o Pake positive ass

37) has shown, cont

*3 BJ-:N stretch i

S"-1 and not a- 1

ds vhich are obsi

sul of couple ng

I is interesting




n a


7ts wi hout

Stc previous

kyl arnine bor

12 cn

at 11 1

i -N roions

noie that si



ly r.


nd also

50 crn-

'ith ci

?rar= px

-aed tra exc t

he 3-N stre ch-

ere t assi able,

,n cf -he spectrum;

ore difficult it

de aied study.

I d s'si n ts

:urs in e; region

s sted hat the

in ciine cranes

ory prjicts ric

for h

ing vi

for i

d i :O,

DC -.eT


are Q



peaks in the D-H stretching region for a '-"-pe molecule resulting

from symmetric and asymmetric stretching' motions. ~ ntrary to this,

the r'ajority of the boron cations studied in this .*ork had three peaks

in the B-H stretching region (a band at 2470 cm-1, a slightly weaker

band at 2400 cm-1 and a weak band at 2350 cm-1). That additional peaks

are oDserved has been explained on the basis of an ineraction between

vibrational levels associated with two different vibrations cr com-

binations of vibrations (39,44,45). This pheno enon, called Fermi reso-

nance, arises when two closely spaced vibrarional energy levels of the

same symmetry species interact. Often it is seen '.hen a funcanental

and an overtone or combination band interact, eigenfunctions of the

latter type absorptions exhibit fundamental character and intensity.

When this interaction occurs, the energy levels repel znd one vibra-

tionai level is raised and the other lowered relative to the unper-

turbed state. Similar reasoning has been applied to a number of al-

dehydes possessing additional C-H stretching vibrations (46).

The B-H stretching frequencies of the 3H2 group in the cations

are shifted to higher frequency compared to the B-H stretching frequen-

cies of the 5H3 group in 2,2'-dipyridylamine bisborane and to the

B1 group in dihydro[(2,2'-ir-minodipyridinato)(1-)-N N1 ]boron. Both

of these were broad bands from 2280 2460 cm- with a great deal of

structure which is typical for an am;re borane. The B-H a sorptions

for dihydro[(2,2'-iminodipyridinato)(1-)-N Q 1 ']boron-bcron trifluoride

(1:1) were very much like those of the cations. There were three B-H

stretching vibrations in the region 2350 2500 cm-1

in the compound fluo:-ohydro (2,2'-:rminodipyridine-J ,NI)'

Doron 1 i+) hexafiuorophosphate there was a single observe at 2480

c i :'ii ch cud bo attri j"ed ,o o-i

[(2,,. -i !in..dip' r i 'ir3Tc)( I- -:!1 ,!! ].'c

a,,:, 3ss' rfi'.... o the 3r-o- q r.^ china ,ib

re hir I f!u rc'


- 1i 11

\ '"* {

di F

1 '


L; jr

n 1,~ ":3;ii


cm- 1

) ( 1-)-

. 1 i '

o ( 1-)-


r: i Cvr~ i n


-i* 1 /V I ... --

1 ..
- - ij I 1 o


- I

SC ... ...

il- - -- j- U,

' I i !

I .j

i-- .. ..--i'n. --
--- 3 -.. . j .
- ----i - -|-.- ^- i -

-. -- --o
-- --------=-~--- T

I - :- >

*-j i j I.
I -

-- ,,,

--- -. ..- .-0-.-- -i

- : .'- I I 1,
--: -.. ... ~.._ ._~ t .. ..


, i , -i i ; t i i NI-

r-- -,

E -
r- ^




__ __ I Ti_ ii _

i 'i

N,N'] boron are shown in Figures 4 and 5.

Fass Soectra

The purity of dihydro [(2,2'-iminodipyridinato)(1-)-N ,N ]
1 1 '
boron, fluorohydro [(2,2'-iminodipyridinato)(1-)-Ni ,N ] boron, di-
1 1'
fluoro [(2,2'-iminodipyridinato)(1-)- ,NI, ] boron, and 2,2'-dipyridyl-

rethylanine :.ere checked by rass spectra. These spectra ,were obtained

on a Hitachi Perkin-Elmer F"'-6E 14odel rass spectrometer over the range

10 300 ainu at 70 V ionization voltage. All the samples were intro-

duced at 100 except that of dihydro [(2,2'-inDinodipyridinao)(1-)-N1

N11] boron which was run at 950. The cracking patterns were compli-

cated but the pattern in the region of the parent peak agreed with the

expected molecular weight values based on natural element abundance.

The important peaks are listed in Table 4.

Nuclear Maanetic Rescnance Spectra

The proTon nmr spectra of the neutral compounds and the

charged salts were taken on a Varian A-GO instrument with tetramethyl-

silane as an internal reference. The 19F nmr spectra were run at 94.1

iiHz with perflucrobenzene as an internal standard. 1B nmr spectra

were run at 32.1 M!Hz with external borontrifluoride etherate as a refer-

ence, and either acetonitrile, nitromethane or methyiene chloride were

used as solvents, in many cases the N-H and B-H resonances were either

very broad or could not be found, but, except for these protons, the

integrated intensities of the proton spectra agreed weil with the ex-

pected values. The chemical shifts, , in parts per million and cou-

pling constants, J, in Hertz (Hz), of proton resonances, fluorine reso-

n-cnces and boron lesonances are reported in Tables 5 to 9, and also have


'ass Spr:c-'lra Data

Dihy c-o[(2,2'-i in di p r-idi a o)(1-)-1,1 1' boron

m/e I n ns ity Ass i nent

1 :5 2 13C 12C 11B

1-" 14 13, 1- 11,
1 -9 10 3

IP-' 1 1 11

1 15 1

D i fI L "(- 2,2 '-ir incdi rid i o 1-) ,1 ] oron

e Int nsity ii n

221 4 13 11..
S3 2

15 12 11.
1 9 6-3 '2

2 19 1 1V 11
"1G '3 2

218 7 12 C 11
I :. 2

Soroh r ro[(2,2'- i n

m/e Intens it

201 4

: 0 18

?i- 4

idi r i ( -)-

y AssignmenT

13 12 C9 N 11

i12 9 3H B
I0 9 3

12, 1
10 8 3

12 11
flO 6 73ll

TABLE 4 (Continued)








13C 12C 10H 1N
1 10H11

12 H N
11 11N

12C H


I--J' "-111---------~--`---- ---'-



Proton ":'. -. a of PF Sa ts

I +n

-I I
X2 Xp

Ar -*,z ic flo: ons j

Conp unds S m

1 I; = H; X H; n = 1 -7.53 m
"1 -F.27 in

X1 = ; ; X3 F; n = 1 -7.73 m
-1 P.26

SF; n = 1 -7.67 m
S-8.48 m

icb -. -2.63 s
X H; X2 = H ; X1 = i-pic -?. m

n 2

C X H; X ; n = 1 m -3.73 s
1 .34 m

S -Is: i, ultiplici y: s, si le ; m, cor ex u It iplet

b -pic = 4-rathylpyridine

been presented wi-h the synthesis of the compounds in Chapter III.

The proton spectrum of 2,2'-dipyridylamine shc'..ed three mul-

tiplets at -6.63 ppm, -7.60 ppm, and -8.23 ppm from internal tetra-

inethylsilane with intensity ratios of 1:2:1 respectively. The cations

(BE'2, BFH, -;:2) all showed a definite downfield shift (Tables 5 and 6).

If the an ion wa.s hexafluorophosphate, there were two multiplets with an

intensity ratio of 1:1, but if the anion was a halide, the multiplets

had an intensity ratio of 3:1 (the most downfield multiplet being of

intensity ratio 3). The neutral adducts were in the same region as

the i'reo ainine but exhibited only two multiplets of intensity ratio

1:1 (Table 7).

As a fluorine atom was substituted for a hydrogen atom on the

boron portion, in the neutral adducts, a downfielJ shift occurred with

only a v,:-y slight reduction in the separation between the tvwo mul-

-iplets. This ws expected, for previous work had shown that halide

substitJ;ic. on boron in cations containing substituted pyridine

caused a downfield shift of the aromatic protons (47,48,49).

The cations derived from proton addition to the neutral ad-

jucts with hexafluorophosphate as the counter ion all showed a down-

field shift with fluorine substitution,with the separation between mul-

tiplets again decreasing with increasing fluorine substitution. The

largest relative downfield shift and the greatest relative decrease in

mu;tiplet separation occurred with monofluorine substitution. In the

ha ide salts of the BH2 cations, there was a slight downfield shift on

going from chloride to bromide to iodide, although both multiplets did

not shift s;,nilarly (Table 6).

The proton nmr of the hexa1-;uorophosphate sal of the N-inethyl-

T'L E 6

Froton a o A I icde Sa ts

+ I



-.c..... ic P :,


-8. 12

-7. '

Is: Tmu, J pIipl ioi r,
mu 1- i p i et




'o I ex




Proton ''."- Data of N'eutral Adducts

2 3

Arociratic Frotons


X = -; X2 = H; X = H

X -- X2 = H; X = F

X = -; X2 = F; X3 = F

I = BF = H; X= H

X = B.F; X2 = F; X3 = F

"Symbols: M, multiplicity; m, complex multiplet

S ppm






TA 7;

113 N''R Data of S lts


and '- urralI Adducts

+- n



X2 X3

C -unds S J Hz a

S= H; X = H; 6.0 0.6 3

4 = I; n 1

; X H
6.7 3
4 -6; n =

i; X =

-; n = 0

; = F; X- = F;

4 PF6; n = 1

.9 -.6


: M, multiplicity


19F .'- Data of Fluorinated Co-mpounds

- n


X1 = H; X2 = F; X = F;

X = PF ; n =

S= -; X2 = F; X = F;

X4 = -; n = 0

S, ppm


-25. 1


J, Hz U,

J-F = 740 2

J -F= 25 4

JB-F = 29.5

X= H; X2

X4 =

X4 =

F: X H;

PF6; n = 1

F: X3 = H;

- n = 0

X; = BF3; X2 = H; X3 = H;

X4= -; n= 0

XI = 8F3; 3X = F; X3 = F;

X4 =-; n= 0








P-F = 707

JB-F = 77.1

JH-F 64.2

JB-F= 16.5




"Symbcl : 'i, multiplicity; B, very broad band

-~-I--- ---~-~



-. ..s it J cation exhibited in the arctic region tw rultiple s of

in:-. ,Li : ratio 1:1, with a iOst the Ss3 cie- 'ical shift a- s The hexa-

fluor hos ate: salt of the cat i en with a -c:n on nirroe .

The roton nmr of 2,2'-dipy idyl eyla i ire v:as shif-od down-

ild nation. er was vry little shift of t-e mehyI group

i-csnc nc u he arc tic resoAn7a cs tehe. d I ire dif:feren- ly~I. In the

5. n here Y t oo ,.f i. ensi'f


cai nO-

un I

end >;en

1 191

. 1 -2 .

sulbs:; :tu

ri 1 r e-r-

I hi f of

) ( -)


Si nte



.: a ofC

itet of

o J and J-F eir alos

spectra were run on only few

a iripleT although the onl

uiat o [ C(2,2'-i min

-H;,s about i110 z. The ot.he

ets but t daa werie obt ned

r c r r in

S1 'n
-, bcrcn and

nd r sectively

a io 1:2:2:2:1

-co ~ nds (Table 8).

Ie v se coup li ng

, ipyridinato)( 1-)-

Sconpounds were

using an ccillo-

A l I1


N! ,, 1


ot:iined ::as

The 11B

intc coJd be

r ir -on.

ble 9

due t


ca ic



D ..nf i i

. D f i n i


D IS i 3CN

o':-cuse Te systematic rnnes of ,any compcl ds discussed here

, 7 tir'ss b eilher very long or cuimbbr cme, 1'0i cc uns will

toC ("?( '. signedd a number. Fro th n on, cnly the nu i'-.. : be

.on A I:Io.-s -ta' c~'~d as an a: -ndix to This di i era i n, wi ll

i I i ;r, a : n s ructure in es cin for

r- y r r r.. A arevia ic'is are also l ist d her in p .I a ical


', in I ,n -i e

n, i nr i -at cnt ac imi i
i n .i s I

( .:. 1I) .: s a l ';

S:1@. r :

! i ,W ridinaTo )(I-)- r n (C

The firs. T ': o i.

id. i s c sc t. Tr in hy I ii ne-m

d tu r ct wiTh 2,2'-dipyridylarine (C

a; bs explained by the following reac

lit j ~-~I _


I ad


\) in

C ion


N i ~I1I I~


! I

I + T M A

I ?

1 1

c [i ,

TM' A H -

H I-- \ H

( ) i

T- j I i 1-

i c i cJd- (

I i ine i


L" )


- I -i TI r"- -n

1 .

hours. This sj -.-ted that amine <.as retained in solution by some

crmica I means. The intense yellow color of the benzene solution

during. he reaction could also suggest the presence of a species un-

expected at the time of the first experiments. It was later shown

That there is an equilibrium (c and d) which can be shifted almost

ccr,,pletely to yield the cyclic boron cation and free TM'A. The iodide

salt or the boron cation ( l) can then be readily converted to the

neural zwitterion (I) by any number of bases. The existence of such

an equilibrium was demonstrated by a number of related experiments.

A flask was charged with a magnetic stirring bar, TI'AHI, (I),

and dry benzene. The mixture was brought to reflux and TN'A evolution

w'.:s ,otriced. W''hen TI'A evolution ceased, a light yel low solid re:ained

in the flask and was identified by its infrared and proton norr spectra

to be the icdide salt of (11). Once (11) was formed, the imniro prooinI

could be removed by bases such as sodium hydroxide or alkyl amines.

The quantitative protonation of (1) to produce (ll) could

readily be accomplished by bubbling into a methylene chloride solution

of (i) anhydrous hydrogen chloride or hydrogen bromide until the

charcteristic yellow color of (I) disappeared. This constituted a

convenient method of preparation for the chloride and bromide salts of

(ii), wh;ch because of their solubilities could not be prepared by

precipitation from aqueous solution.

The results of the experiments with Ti."AHI and (1), HX and

(I), and proton removal from the iminc nitrogen in the boron cation

( I wi ih sodium hydroxide, diisopropylamiine and di isopropyl ethylamine

led to the conclusion that equilibrium (c) and (d) does in fact occur.

T.- !ieth'larin: is a strong enough base to remove a proton from the

buron a-ion (1 ) to form an rn

r-sscn i tr iethylamine ak,

and that ihe intense yelev; col

tericn (I) can be served so

The second hd or

has lss direc+ pIec d,? T

onium ion. This is essentially the

e eiy icng 1i r to c se evolving

:r chracoer is ic f neutra zit-

ortIy after ixing of e reacrants.

ihe pri on of ( ), and

n it '"ail d r)"c2 ei n":os

l-. cr ; lc s *to "ud ce (I).

T A B H 3
0 PA

Activa-ion of

-3) -3nd c ulId

a B'm-. &a la.

to produce h'

(A) can te:n


(A) H

N 1-


ccidi' by rccrdinra icn 'o

fed o cccur cne a DF' I

to the rescti icn of barc'nler ii

i i i

foT torn a Dona

y prevent this,

-oxirrit, and cc

ie pKa's cf +

imi lar. ?h

Oin f a fcur-

borane, The c'

nd form an dd(

n for the ster

-it pyric

i ly s rve as z

2e r i ro ar

--> T) + H,

his 0en sown ( ,

"as becc,:,e cordinaTed to

it n iu ion

or i na -ed i nered i ate

cr.i i i no nitro-

-ic r ire +s vould

dine ni-r wuld be

Sdonr site.

d the amino ni rogen

a stabl board Tr boron,

,pec1 io !at of a six-



in N 3

r m. erd rino *;yse e -s to The p -eferrec product.

ps o bro iria hexa ruorc hospha salt or (II)

Wv;-ri b: ine produced a cc( pleely un expected result. Instead of

7. t!i the expected bromina ed producer, a fluorinated product, di-
1 1 '
fluoro (2,2'-iinodipyridine--. ., ) boron (1+) hexarI uoroph sphate

ill) was isolated.

The reaction of the hexaflucr 'osphato sal of ( II ) with

hrc ine ro produce (III) most likely occurs by initial brcnination at

oroq ard subsequent Fluorination. The res ult of the experiments

'.,'ith t e ;exaii uorophosphate sa I of (II) with brcrni and hydr- n

'i-r ii '- 5:i -he brcmide salt of (II) with bromine and r i o niur hexa-

f I l : ris phate see to substantiate fhot bromi ni ion is fol l owed b

Suori t ion.



Or H


+ P + H Br

( III )

it has been demonstrated (47) that bromine w\ili react with

hydrogens attached to boron in boron cations +o produce F'r and a

cation which ras bromine substiii-utc on boron. chese bromo-substi-

+uted catiors are hydrolyticaly unstable and rhe brrnine can De dis-

placed by an a iine. To determine if bromination was a needed first

eiep or if bromine hexaf uorophospnare was the fluorinating agent,

I'N -

+ Brq

i' 27- ,

er 'ir .das run.

n rr, e %as

or D i)

I J 1 .

firs-, steo and hat -he system bromine -PF is net- ',

e ;-j IFthe. fIeT'.c" the fluorinating a ent is PFs, ,

ion lies nc been determined. It has been deonsra-ed

lcc'-pose to I and PF5 in strongly acidic media (40)

sol cnts fluoride ion is a strong nuclephi le and could

brc i d e.

f I r ini f i nc

d PF or F

ha- F- wi ll

in non-- ,eous

easi Iy displace

That difluorination occurs can

)e explained by

tie fo I ow i ng.

H -i- 2



X = Or F

Iydride io 's appears to be easier in the cholate caticn (A) -ian in a

no;-.:he laed system. Once a halide is attached to boron, a trigcnal

intermediate (B) may be formed. Multiple bonding by the hal ide to

boron migh- facilitate hydride loss.

To demonstrate that hydride loss is ea r in the chelated

ys-f-emi (A) and to test the feasibility of using bromine and hexafuoro-

-,hosphate as a general luorinating agent, the fol lowing reaction vwas

r un .

A F;ask v;as charged with a majie-tic stirring bar, bis (4-

picoline) boronium hex:afiorphosphate and dry C-lNO2. VWith stirring,

bi)orine was added drcpwise. The bromine vws immedia-iely decolorized

up intil the last portion was added and then the reaction mixture re-

aineo, a light orange. The reaction vessel was stcppered and a lowed


*O cC r oUt

U rPuner


X Br ,

2T ache

-a is p

Id vie d ( f i ) .

(3) + F-


Tr ',^'.a Ti ,r- s~ r' i i; .r c o p -T7Cn1

I ur n; rc, -I

t c r

f uorinate directly.

The reaction of triphenyi:-._Thyl chloride and the hexafluoro-

phosphate salt of II) to produce fluorohydro (2,2'-iminedipyridine-

N1,N ) boron (1+) hexafluorophosphate (IV) most likely occurs by hy-

dride abstraction followed by fluoride addition. It has been demon-

strated that triphenylmethyl carbonium ion is able io abstract hy-

dridic hydrcgens from boron in amineboranes (52). When donors are

present in the system such as amines or acetonitrile, they readily

form adducts .-ith the resulting bcrcn species. In the case of hy-

dride abstraction from the hexafluorophcsphate salt of (II), the two

most obvious donors wculd be a chloride ion or a fluoride ion from

PF6 Because no chloro-substituted products were isolated, three

possibi cities must be considered. The first is that the rono-chlcro

substituted product may be hydrolytically unstable and decompose upon

aqu eous work-up; the second is that the chlorinated prcd~uc 'e'.cr forms

and a fluorinai-cd product forms immediately; the third is mhat if a

chloro-substituted product does form, the chlorine is displaced by a

fluorine. Since yields are low, all three possibilities exist. if all

-iree possibilities aid occur, the premise that the mono-chloro-sub-

stirutcd product 'was hydrolytically unstable would Icwer the yield of

(iV) by 30 to 50 percent. This assumes thai all The possibili-

ties have an equal probability of occurring, (IV) is hydrolytically

stable and there is an equal chance for a chloride or fluoride io ini-

Tially become bonded to boron after hydride abstraction has occurred.

That the chloro-substituted product is unstable to hydrolysis

is suggested by several observations. If one bubbles chlorine through

(!) ;or e short period of time, no stable product can be isolated,

+ Cl --)> I CI

N C lN i

the above ract-ic

the reguli r ca

that ; n a

b'I a chlorine .as su asl ituted

I' h "'rolyzed. I,- a s carl ier

si cC on orcn is a bcron

i ly.


o reai

v can

)n anJ

i so

Sad the only nucle

reasonablee TO assume i

a ch I or ie-ubst itiu ed

ile in he

'% 2' ri-

Sduci con-

wcrk-up. ,at

t bsract ion

ri i n. It

aced a hydride

+ ,CC --->



ai, iogh a solid is fcrred .,hich rapidly jecrpcses .on exposure to

the a 0:sphere.


H H1


, boron and

icn s it rated

3t ion, That

is a I, l

phenyl e-

1"i s :

did yield

is nor u

t"c yield



'e re uI ti neutral species apparent ly dor n .cpr at-i- -'ed

aqu .o's rork-up.

Thia- a, acidic cas forms above the rec'ticn -ixsture is

prc!:1biy due to traces of .jater in the solvent. is acidic _

nay a .in aid in fluor-ination by assisting the forrat icn of HF, P-F

species and flucride ion which rray be responsible ,or rhe production

of io di fluoro derivative as an i purity. Af-ier hydride abstraction

rs occurred, n intermediate containing a i-rional cron wi I be

>r'hn 3d.



This is ita sr e t'pe of intermediate that led to dif uori -i iin in

T-e prosncis of ,6 and an acidic g>s. Because 4e siflr i eria-

+iv-; (l i ) :.s i'oia-,ed in a very s:'l? I yield when li it le acid ,as

go rared, implies thal acid is needed along with PF :6 produce di-

f!uc i;nation and that The absence o acid n, iniir.izcs the da c position

o, F to F HF, and P-F containing products ''iic, enhance difluorina-

tiop. Without acid to decompose PF6 the only source or Fluoride ion

;s 'F One could envision a transfer of fluoride ton to a trigonal

boron intermediate and a chloride ion becoming e o phosphorous

to forn a PF CI ion.



+ P : CI -

-- P F- + Ci

oth (1il) and (IV)

a1 of a p'ctn to fcr

o:r,- n ('') and flucrch

i ve ly.

id L k I

to r;mo,e s3 a r

i go-al. In

;- to the ; "7.ino-ni

1I to y nera-;e an c

p anil I e anr

*S f roC a neural

eo}cia1l i e of (I),

pecics. The lack

r ) may ba cne

ha pxri

" extra

), and

,2' -a p r i 1 -i

a neaa i "

(V), an

cf chcr

dine ri n

- i : i i

VI), oe oes front

in ( C ), and(

M ir sta ility.

are joined by a

may e t r 1 durced

a charged

S) otherr

Ano Ther r

unit to

in -c the q

' ion.


N \ ,-- N ^

b, r ;Ow

Nrn (-

boron (G

can be

n dif lu

ro [(

i .s ( I),

i 1 t wC

on1y A i

I ), fcr

re ,

is quite

..sic and

ary A if-

s i tuted

ic systems

-t proton

i pr

rai c


s, in

o a neu-

3han for-

a son

'orm a

stem bv

n.ertad to ncrural z,.i tt ricns

[( ,P '-irin w ip' idira o)(1-)-

'-irir"- p riuinatc (i-)- 1, 1 ]


1T 0

i ),



d (

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