Cationic and Condensation Polymerization of Organometallic Monomers

Chapter 36

Cationic and Condensation Polymerization of Organometallic Monomers Kenneth E. Gonsalves and Marvin D. Rausch Downloaded by UNIV OF OTTAWA on June 16, 2013 | http://pubs.acs.org Publication Date: January 7, 1988 | doi: 10.1021/bk-1988-0360.ch036

1

2

Department of Chemistry and Chemical Engineering, Stevens Institute o f Technology, Hoboken, NJ 07030 Department of Chemistry, University of Massachusetts, Amherst, MA 01003

1

2

1,1'-Bis(β-aminoethyl)ferrocene was synthesized via a 6-step process starting with ferrocene. This monomer was then copolymerized with various aromatic and ali phatic diacid chlorides as well as with diisocyanates, leading to ferrocene-containing polyamides and polyureas having moderately high to low viscosities. The above monomer and 1,1'-bis(β-hydroxyethyl)ferrocene were also utilized as chain extenders. Three types of isopropenylmetallocene monomers were synthesized and subjected to polymerization and copolymerization by cationic initiators: (1) isopropenylferrocene, (2) (η -isopropenylcyclopentadienyl)dicarbonylnitrosylmolybdenum; and (3) 1 , 1 ' - d i i s o p r o p e n y l c y c l o p e n t a dienylstannocene, and related derivatives of each. 5

There i s c u r r e n t l y c o n s i d e r a b l e i n t e r e s t i n o r g a n o m e t a l l i c polymers, s i n c e polymers c o n t a i n i n g m e t a l s might be e x p e c t e d t o p o s s e s s p r o p e r t i e s d i f f e r e n t from those o f c o n v e n t i o n a l o r g a n i c p o l y m e r s . 1""^ Two major approaches t o t h e f o r m a t i o n o f m a t e r i a l s o f t h i s type have i n v o l v e d t h e d e r i v a t i z a t i o n o f preformed o r g a n i c polymers w i t h o r g a n o m e t a l l i c f u n c t i o n s ^ and t h e s y n t h e s i s and p o l y m e r i z a t i o n o f o r g a n o m e t a l l i c monomers t h a t c o n t a i n v i n y l s u b s t i t u e n t s > ^ F o r the t r a n s i t i o n m e t a l s , c o n d e n s a t i o n p o l y m e r i z a t i o n s have a l s o been investigated. However, t h e r e a c t i o n s have g e n e r a l l y been c o n d u c t e d a t e l e v a t e d t e m p e r a t u r e s , and t h e r e s u l t i n g p r o d u c t s have o f t e n n o t been w e l l c h a r a c t e r i z e d . ^ * ^ Ferrocene-Containing

P o l y a m i d e s and P o l y u r e a s

We now r e p o r t a c o n v e n i e n t method f o r t h e i n t e r f a c i a l p o l y c o n d e n s a t i o n o f 1,Ι -bis(3-aminoethyl)ferrocene (1) w i t h a v a r i e t y o f d i a c i d c h l o r i d e s and d i i s o c y a n a t e s , l e a d i n g t o f e r r o c e n e - c o n t a i n i n g p o l y amides and p o l y u r e a s . 9 I n some i n s t a n c e s , we have been a b l e t o ob serve f i l m formation a t the i n t e r f a c e . Moreover, t h e p o l y m e r i z a t i o n r e a c t i o n s c a n be c o n v e n i e n t l y conducted a t ambient t e m p e r a t u r e s i n contrast to e a r l i e r high-temperature organometallic condensation 1

0097-6156/88/0360-0437$07.25/0 © 1988 American Chemical Society In Inorganic and Organometallic Polymers; Zeldin, M., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1988.

438

INORGANIC AND ORGANOMETALLIC POLYMERS

Downloaded by UNIV OF OTTAWA on June 16, 2013 | http://pubs.acs.org Publication Date: January 7, 1988 | doi: 10.1021/bk-1988-0360.ch036

p o l y m e r i z a t i o n s , w h i c h f r e q u e n t l y l e d to u n d e s i r a b l e s i d e r e a c t i o n s . We a l s o f i n d t h a t the r e l a t e d monomer, 1,1 - b i s ( 3 - h y d r o x y e t h y l ) f e r r o cene (2) r e a c t s w i t h d i a c i d c h l o r i d e s and d i i s o c y a n a t e s t o form f e r r o c e n e - c o n t a i n i n g p o l y e s t e r s and p o l y u r e t h a n e s , r e s p e c t i v e l y . Monomers (_1) and (2) a r e shown i n Scheme I . Monomers 1 and 2^ have been s y n t h e s i z e d s t a r t i n g from f e r r o c e n e , u t i l i z i n g m o d i f i c a t i o n s o f procedures o u t l i n e d p r e v i o u s l y by Sonoda and M o r i t a n i H and by R a t a j c z a k e t a l . 1 2 The i n t e r m e d i a t e d i a c i d , 1,1 f e r r o c e n e d i c a r b o x y l i c a c i d , was s y n t h e s i z e d a c c o r d i n g t o the more c o n v e n i e n t procedure o f Knobloch and RauscherA® Monomer 1 was vacuum d i s t i l l e d p r i o r t o use (bp 120°C, 1 mm Hg). D e t a i l s of the s y n t h e t i c r o u t e s a r e g i v e n i n Scheme 1. I t s h o u l d be emphasized t h a t i n c o n t r a s t t o p r e v i o u s f e r r o c e n e - c o n t a i n i n g monomers,13 ± and 2 p o s i t i o n the r e a c t i v e amino and h y d r o x y l groups two methylene u n i t s removed from t h e f e r r o c e n e n u c l e u s . T h i s f e a t u r e m i n i m i z e s s t e r i c e f f e c t s and a l s o enables _1 and 2_ t o undergo the Schotten-Baumann r e a c t i o n r e a d i l y w i t h o u t t h e c l a s s i c a l α-metallocenylcarbonium i o n e f f e c t p r o v i d i n g any c o n s t r a i n t s . 1 4 , 1 5 Polyamide f o r m a t i o n i s v i g o r o u s , e x o t h e r m i c , and i n s t a n t a n e o u s . I n t e r f a c i a l or s o l u t i o n polycondensation, w i t h or without s t i r r i n g , was the g e n e r a l procedure u t i l i z e d f o r the p r e p a r a t i o n of the polyamides and polyureas,l° D e t a i l s a r e g i v e n i n Table I . An i m p o r t a n t p o i n t t o be noted i s t h a t , i n the u n s t i r r e d i n t e r f a c i a l condensation p o l y m e r i z a t i o n of 1 w i t h sebacoyl c h l o r i d e or t e r e p h t h a l o y l c h l o r i d e i n the o r g a n i c phase and t r i e t h y l a m i n e as t h e p r o t o n a c c e p t o r , immediate f i l m f o r m a t i o n took p l a c e a t the i n t e r f a c e . The polyamide f i l m s were removed a f t e r 1 h, d r i e d , and u t i l i z e d f o r t a k i n g e l e c t r o n micrographs. a

Attempts t o o b t a i n m o l e c u l a r w e i g h t s o f these new i r o n - c o n t a i n i n g polyamides i n m - c r e s o l s o l u t i o n have not- been s u c c e s s f u l , due to the v e r y l i m i t e d s o l u b i l i t i e s of the m a t e r i a l s i n o r g a n i c s o l v e n t s . S i m i l a r d i f f i c u l t i e s have p r e v i o u s l y been encountered i n the mole- ^ c u l a r weight détermination o f n y l o n 66 (polyhexamethyleneadipamide). However, t h e i n t r i n s i c v i s c o s i t y v a l u e s g r e a t e r t h a n 1.0 f o r the polyamides o b t a i n e d from 1_ and t e r e p h t h a l o y l c h l o r i d e o r s e b a c o y l c h l o r i d e are comparable t o i n t r i n s i c v i s c o s i t i e s o f n y l o n s h a v i n g number average m o l e c u l a r w e i g h t s between 10,000 and 18,000.16° -jhe low [η] v a l u e s o b t a i n e d f o r the p o l y u r e t h a n e s can be a t t r i b u t e d to premature p r e c i p i t a t i o n from s o l u t i o n and, i n t h e case o f polymers o b t a i n e d from _1 and TD1, t o decreased r e a c t i v i t y imposed by s t e r i c effects.18 19 The polyamides and p o l y u r e a s e x h i b i t e d b r o a d , i n t e n s e N-H s t r e t c h e s around 3300 cm~l. A v e r y s t r o n g c a r b o n y l s t r e t c h i n g v i b r a t i o n was p r e s e n t a t 1630 cm~l. The amide I I band was e v i d e n t near 1540 cm"!. I n a d d i t i o n , sp C-H s t r e t c h e s o c c u r r e d around 3100 cm"! and asymmetric and symmetric s p ^ c-H s t r e t c h e s a t 2950 and 2860 cm~l, r e s p e c t i v e l y . The p o l y u r e t h a n e showed the c a r b o n y l ab s o r p t i o n near 1700 cm"l and C-0 s t r e t c h e s i n the v i c i n i t y of

In Inorganic and Organometallic Polymers; Zeldin, M., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1988.

Organometallic Monomers

36. GONSALVES AND RAUSCH

439

ο CH C0C1, A l C l ? 3

CH C1 , 2

2

3 h

F

v

|

N

50°C, 5 h

0

e f

a

5% NaOCl

I *

^


(58%)

CH OH, H SO 3

2

k

C0 CH 2

1

^

C H

2

^ΞΖΞ^-6Η 0Η

Et 0 2

4 Ï ^ C H

'

3

2

^ ^

(90%)

25°C,

2 h (N )

KCN, H 0

I

2

Th

2

0 H

^^33^CH CH NH

2

THF

3

2

(98%)

«^^^^-CH CN PC1 ,

*

e

(75%)

3

LiAlHt,,

^ ^ ^ C 0

,

F

*

2

L i A l H , A1C1 ^ H

yC^rW

Ec

1

3

2» 3 h

>-=j=^

(85%)

I

(73%)

'NaOH EtOH, Δ H CH OH 2

^

L i A l H i + , THF ^

I ^

2

| H CH OH

H C00H

2

2

2

2 (70%)

(98%)

Scheme I .


2

2


440

f

Table I.

Polycondensâtion Reactions between 1,1 -Bis(3-aminoethyl)ferrocene (1) and (3-hydroxyethyl)ferrocene (2) with Diacid Chlorides and Diisocyanates


monomer (M^ i

a

i

a

i

a

i

a

i

a

process (base used)

(M ) 2

% yield dL/g

e

UI (Et N)

72

1.50

sebacoyl chloride (CCl^)

UI (Et N)

85

O.37


UI (NaOH)

39

O.59

terephthaloyl

chloride ( C I ^ C l ^

b

3

3


I

(Et N)

51

1.09

adipoyl chloride (CCl^)

UI (Et N)

47

O.53

45

O.80

51

O.16

S

46

O.20

TDI (CHC1 )

UI

58

O.16

TDI (CHC1 )

S

53

O.10

S

67

f

1

terephthaloyl

2

terephthaloyl

b

3

3

chloride(CH C1 ) 2

2

S

b

S

chloride

(Et N) 3

(pyridine)

(m-xylene, reflux) 2 i 1 1

TDI° (Me S0, 115 2

a

°C)

3

3

MDI

d

Monomer i n aqueous phase b

UI, unstirred i n t e r f a c i a l S, solution I, S t i r r e d i n t e r f a c i a l C

TDI: tolyene 2,4-diisocyanate (80%) +2,6,

isomer

(20%)

d

MDI : methylenebis(4-phenylisocyanate)

6

I n t r i n s i c v i s c o s i t y determined

i n m-cresol at 3?°C

^insoluble i n m-cresol 1220 and 1280 cm ^. Similar absorptions were present i n the polyester. The polyamides and polyureas are thus assessed to have structures outlined i n Scheme I I . Model Compounds. Further elucidation of these polymer structures was done by synthesizing model analogs. 20 It has been demonstrated by Hauser and coworkers that 3-aminoethylferrocene (_3) undergoes reactions t y p i c a l of the amino funct i o n a l group.

Fe


GONSALVES AND RAUSCH



36.


441


442


They showed t h a t _3 a f f o r d e d a p i c r a t e on b e i n g t r e a t e d w i t h s a t u r a t e d a l c h o h o l i c p i c r i c a c i d and formed N,N,N-trimethyl-3-ferrocenylethylammonium i o d i d e on b e i n g t r e a t e d w i t h m e t h y l i o d i d e . 3-Aminoe t h y l f e r r o c e n e (3) was s y n t h e s i z e d by a m o d i f i c a t i o n o f t h e l i t e r a t u r e method^O and was c h a r a c t e r i z e d by e l e m e n t a l a n a l y s i s , IR and -4i NMR s p e c t r o s c o p y . Following the procedure of Pittman e t a l . , ^ 1 the m e t h i o d i d i d e o f Ν,Ν-dimethylaminomethylferrocene was c o n v e r t e d t o f e r r o c e n y l a c e t o n i t r i l e by r e f l u x i n g w i t h sodium c y a n i d e i n deoxygenated w a t e r . The l a t t e r compound was then reduced t o t h e amine _3 w i t h L 1 A I H 4 . I n o r d e r t o i s o l a t e pure _3, i n s t e a d o f p a s s i n g hydrogen c h l o r i d e gas i n t o an e t h e r s o l u t i o n o f 3,^° 6N H2SO4 was used. The p r e c i p i t a t e d ferrocenylammonium s u l f a t e was f i l t e r e d under n i t r o g e n and t r e a t e d w i t h aqueous sodium h y d r o x i d e t o o b t a i n t h e f r e e amine _3 i n the o r g a n i c l a y e r . Pure 3 - a m i n o e t h y l f e r r o c e n e (3) was ob t a i n e d i n 70% y i e l d by d i s t i l l a t i o n under*vacuum (b.p. 120°C/1 t o r r ) . A s u s p e n s i o n o f 3 - a m i n o e t h y l f e r r o c e n e (_3) i n deoxygenated w a t e r , c o n t a i n i n g an excess o f sodium h y d r o x i d e , was found t o form a y e l l o w p r e c i p i t a t e i m m e d i a t e l y on b e i n g shaken v i g o r o u s l y w i t h one e q u i v a l e n t o f pure t e r e p h t h a l o y l c h l o r i d e i n d r y benzene. E l e m e n t a l a n a l y s i s and an IR spectrum i n d i c a t e d t h e y e l l o w p r e c i p i t a t e t o have t h e s t r u c t u r e h_ ( y i e l d 100%) .

I n _3, t h e amino f u n c t i o n a l group i s two methylene u n i t s removed from the f e r r o c e n e n u c l e u s . I t appears from t h e i n s t a n t a n e o u s and q u a n t i t a t i v e f o r m a t i o n o f 4_ from _3 t h a t t h i s f e a t u r e m i n i m i z e s s t e r i c e f f e c t s and a l s o e n a b l e s _3 t o undergo t h e Schotten-Baumann r e a c t i o n r e a d i l y w i t h o u t t h e c l a s s i c a l α-metallocenylcarbenium i o n e f f e c t s p r o v i d i n g any c o n s t r a i n t s . ^ The IR spectrum o f 4^ showed the c h a r a c t e r i s t i c N-H s t r e t c h a t 3320 c n T M s ) , t h e amide 1 ( c a r b o n y l ) s t r e t c h a t 1625 c m " ( s ) , t h e amide I I (N-H) s t r e t c h a t 1540 c m " l ( s ) , and t h e amide I I I band a t 1310 cm~ (m). I n a d d i t i o n , c h a r a c t e r i s t i c a b s o r p t i o n s o f t h e f e r r o c e n y l group were e v i d e n t a t 1100 and 1000 cm"l ( i n d i c a t i n g an u n s u b s t i t u t e d c y c l o p e n t a d i e n y l r i n g ) and a t 800 cm~l. 1

1

I n a d d i t i o n t o t h e above r e a c t i o n , 1 , l ' - b i s ( 3 - a m i n o e t h y l ) f e r r o c e n e (3) was r e a c t e d w i t h two e q u i v a l e n t s o f b e n z o y l c h l o r i d e


36.




i n the presence o f t r i e t h y l a m i n e . A p r o d u c t (5) whose spectrum c l o s e l y resembled t h a t o f 4_ was o b t a i n e d .

443

infra-red

As b e f o r e , an N-H s t r e t c h was observed a t 3325 cm ( s ) , t h e amide I a t 1650 c m ( s ) , amide I I a t 1550 c n T ^ s ) , and amide I I I a t 1325 cm"l(m) . _ 1

I t i s w e l l e s t a b l i s h e d t h a t p r i m a r y a m i n o - f u n c t i o n a l groups, p a r t i c u l a r l y a l i p h a t i c ones, r e a c t i n s t a n t a n e o u s l y w i t h i s o c y a n a t e s t o form ureas a t ambient t e m p e r a t u r e . Indeed t h i s was o b s e r v e d when β-aminoethy1ferrocene (3) and f r e s h l y d i s t i l l e d p h e n y l i s o c y a n a t e were shaken v i g o r o u s l y . A y e l l o w p r e c i p i t a t e s e p a r a t e d out immedi a t e l y . E l e m e n t a l a n a l y s i s and an IR spectrum o f the p r o d u c t i n d i c a t e t h i s compound t o have the s t r u c t u r e 6^.

Fe

The c h a r a c t e r i s t i c a b s o r p t i o n s o f t h e u r e a group were e v i d e n t i n t h e IR spectrum: -NH s t r e t c h 3320 c m ~ ( s ) ; amide I 1625 c n T ^ m ) ; amide I I 1560 c m " ( s ) ; amide I I I 1240 c n T ^ m ) . The y i e l d o f 6^ was a g a i n q u a n t i t a t i v e . When t h e diamine 1 was s i m i l a r l y r e a c t e d w i t h p h e n y l i s o c y a n a t e , a y e l l o w p r e c i p i t a t e was observed i m m e d i a t e l y . The IR spectrum o f t h i s p r o d u c t (7) was s i m i l a r t o t h a t o f 6. The -NH s t r e t c h o c c u r r e d a t 3300 cm"~l(s) and t h e c a r b o n y l a b s o r p t i o n a t 1630 cm"" (s). The amide I I band o c c u r r e d a t 1550 cm~"l(s,br) and t h e amide I I I a t 1260 αιΓ^ιη). 1

1

1


444



Segmented P o l y ( e t h e r u r e t h a n e ) F i l m s C o n t a i n i n g F e r r o c e n e the Hard Segments

Units i n

Segmented p o l y ( e t h e r u r e t h a n e s ) were s y n t h e s i z e d from p o l y p r o p y l e n e g l y c o l (PPG) and 4,4 M e t h y l e n e - b i s ( p h e n y l - i s o c y a n a t e ) (MDI), u s i n g l , l - b i s ( $ - a m i n o e t h y l ) f e r r o c e n e (1) and 1 , 1 - b i s ( β - h y d r o x y e t h y l ) f e r r o c e n e (2) as c h a i n e x t e n d e r s . f

T

Synthesis o f Polyurethanes. I n t h e "prepolymer method" employed i n t h i s s t u d y , MDI (2 e q u i v a l e n t s ) and PPG (1 e q u i v a l e n t ) were r e a c t e d a t 60°C i n t h e p r e s e n c e o f 1% d i b u t y l t i n d i l a u r e a t e as c a t a l y s t , i n the m e l t . The c o u r s e o f t h e p o l y m e r i z a t i o n s was f o l l o w e d s p e c t r o s c o p i c a l l y by o b s e r v i n g t h e i n t e n s i t y o f t h e ^NCO peak i n t h e IR (Scheme I I I ) . MDI i t s e l f e x h i b i t s a s t r o n g NCO peak a t 2260 cm ^. A f t e r t h e above r e a c t i o n had p r o c e e d e d f o r 30 min, a s m a l l a l i q u o t was w i t h drawn from t h e r e a c t i o n v e s s e l and i t s IR spectrum r e c o r d e d . I t showed a s t r o n g a b s o r p t i o n a t 2260 cnT^ c h a r a c t e r i s t i c o f t h e — N C O group. S i m i l a r l y , a f t e r 60 min t h e a b s o r p t i o n f o r —NCO was s t i l l strong. The p r e p o l y m e r thus o b t a i n e d had r e a c t i v e — NCO groups. When t h i s prepolymer was c u r e d i n a vacuum oven f o r 12 h a t 60 C, the r e s u l t i n g m a t e r i a l a l s o e x h i b i t e d a s t r o n g broad a b s o r p t i o n a t 2245 cm~l. L i k e w i s e , a s i m i l a r prepolymer allowed t o cure a t c a . 20°C i n a i r showed t h e above a b s o r p t i o n . Thus i n a l l c a s e s , t h e p r e polymer p o s s e s s e d r e a c t i v e i s o c y a n a t e end groups. A f t e r t h e MDI and PPG had r e a c t e d t o form the p r e p o l y m e r , 1 (1 e q u i v a l e n t ) i n d r y DMF was added as t h e c h a i n e x t e n d e r . The r e a c t i o n was then c o n t i n u e d a t ambient t e m p e r a t u r e , c a . 20°C, f o r 3 h followed by c u r i n g a t 20°C f o r 24 h i n vacuum. No i s o c y a n a t e group a b s o r p t i o n was observed i n t h e IR spectrum o f t h e b l o c k p o l y ( u r e a u r e t h a n e ) polymer ( B P U l a ) . A l t e r n a t i v e l y , t h e c u r i n g was a l s o c a r r i e d o u t a t 60°C i n a vacuum oven f o r 24 h . No i s o c y a n a t e group a b s o r p t i o n was o b s e r v e d i n t h e IR spectrum o f t h i s polymer (BPU1). However, t h e d i f f e r e n c e i n c u r i n g p r o c e d u r e s p r o d u c e d dark brown f i l m s h a v i n g d i f f e r e n t s o l u b i l i t i e s . The former was s o l u b l e and t h e l a t t e r i n s o l u b l e i n DMF. The complete d i s a p p e a r a n c e o f t h e —NCO peak i n t h e IR s p e c t r a of these dark-brown t r a n s l u c e n t f i l m s i s a good i n d i c a t i o n t h a t com p l e t e c h a i n e x t e n s i o n o r c u r e had o c c u r r e d . I n t h e l a t t e r case,


36.

GONSALVESANDRAUSCH


445

(MDI) + CHrr-H>-CH--CH -^ OH Downloaded by UNIV OF OTTAWA on June 16, 2013 | http://pubs.acs.org Publication Date: January 7, 1988 | doi: 10.1021/bk-1988-0360.ch036

2

r

(PPG) Dibutyl t i n dilaureate Δ 6 0 C , Melt e

-IL-* NC0:

30 mi η

V

-1 cm 2260 (s)

30 min PREPOLYMER

-^

V

NC0

cm M2260 ( s ) 1730 ( s )

20*C/3 h

e

DMF,60C/3 h

cured a t 20 C f o r 24 h e

viscous residue

No NCO peak i n IR (BPUla)

cured a t 60 C f o r 24 h e

No NCO peak i n IR (BPUR2)

cured a t 60°C f o r 24 h No NCO peak i n IR (BPU1)

Scheme I I I .



446

however, the i n s o l u b i l i t y o f the f i l m i n DMF a l s o i n d i c a t e s t h a t b i u r e t b r a n c h i n g and c r o s s l i n k i n g c o u l d have o c c u r r e d on c u r i n g a t 60°C f o r 24 h, as might be a n t i c i p a t e d .


The above prepolymer on treatment w i t h 2_ as the c h a i n e x t e n d e r i n dry DMF d i d not proceed a t ambient temperature. The m i x t u r e had t o be h e a t e d t o 60°C f o r 3 h b e f o r e the r e a c t i o n was complete. A f t e r c u r i n g a t 60°C f o r 24 h, the y e l l o w , t r a n s l u c e n t b l o c k p o l y u r e t h a n e f i l m (BPUR2) a g a i n showed the absence o f the —NCO peak i n the IR spectrum i n d i c a t i n g t h a t c u r i n g had been complete. The f a c t t h a t a h i g h e r temperature had to be used i n the case of 2_ as the c h a i n ex t e n d e r compared t o 1. i s i n k e e p i n g w i t h the lower o r d e r o f r e a c t i v i t y of d i o l s w i t h d i i s o c y a n a t e s as compared to diamines w i t h diisocyanates. On the b a s i s o f t h e i r i n f r a r e d s p e c t r a the polymers BPUla and BPUR2 were a s s e s s e d t o have the s t r u c t u r e s 8 and 9_ r e s p e c t i v e l y , as g i v e n i n F i g u r e 1. 1

Polymer BPUla showed the c h a r a c t e r i s t i c NH s t r e t c h a t 3350 cm a l o n g w i t h the c o r r e s p o n d i n g amide I and I I a b s o r p t i o n s a t 1 7 3 5 ( s ) _ ^ and 1530 (br) cm" r e s p e c t i v e l y . A c a r b o n y l a b s o r p t i o n a t 1650 cm was a s c r i b e d to the urea group i n t h i s polymer. A s t r o n g C-O-C (br) peak a t 1100 cm" and CH s t r e t c h e s at 3050, 2940, and 2860 cm" were a l s o observed. The polymer BPUR2 a l s o showed the c h a r a c t e r i s t i c — NH s t r e t c h a t 3300 cm" and the amide I and I I a b s o r p t i o n s a t 1720 (s) and 1530 (s) cm" , r e s p e c t i v e l y . A g a i n the C-O-C s t r e t c h was observed a t 1100 cm" and the CH s t r e t c h e s a t 3050, 2940, and 2860 cm" . These c o r r e l a t i o n s compare w e l l w i t h t h e IR s p e c t r a o f s i m i l a r segmented p o l y u r e t h a n e s . " 1

1

1

1

1

1

1

The i n c l u s i o n of _1 as an i n t e g r a l p a r t o f the p o l y u r e t h a n e system was c o n f i r m e d i n the s y n t h e s i s of B P U l a . A f t e r the r e a c t i o n had been completed, the m i x t u r e was poured i n t o e x c e s s d i e t h y l e t h e r , r e s u l t i n g i n a y e l l o w g e l a t i n o u s p r e c i p i t a t e . The y e l l o w v i s c o u s m a t e r i a l was s e p a r a t e d and a l l o w e d to cure a t ambient temperature f o r 24 h. The r e s u l t i n g t r a n s l u c e n t y e l l o w f i l m was s o l u b l e i n DMF. The amount of i r o n determined by e l e m e n t a l a n a l y s i s i n t h i s sample was 1.1% (4% f e r r o c e n e ) . Thus the IR s p e c t r a , e l e m e n t a l a n a l y s e s , as w e l l as p r e c i p i t a t i o n procedure f o r BPUla a l l p o i n t towards the i n c l u s i o n of 1 i n t h e p o l y u r e t h a n e s v i a c h e m i c a l l i n k a g e , and not by j u s t mere p h y s i c a l compounding. The p e r c e n t a g e of i r o n i n the o t h e r p o l y u r e t h a n e s , BPU1 and BPUR2, were determined to be a p p r o x i m a t e l y 1.9 and 1.2%, r e s p e c t i v e l y , c o r r e s ponding t o 6.7% and 5% f e r r o c e n e u n i t s i n t h e copolymers. The m o l e c u l a r weight d i s t r i b u t i o n (MWD) o f the l i n e a r p o l y u r e thanes were determined by GPC. The s o l v e n t used was THF and the i n s t r u m e n t c a l i b r a t e d _ b y narrow MWD p o l y s t y r e n e s . Polymer BPUla had an M of 56,000 (M :12,500); and BPUR2 M o f 97,000 (M :9,100). w η w η Mass S p e c t r o m e t r y . Mass s p e c t r o m e t r i c (MS) a n a l y s i s has been u t i l i z e d f o r polymer and copolymer s t r u c t u r a l i d e n t i f i c a t i o n ^ . Recently Dussel et a l . u t i l i z e d pyrolysis-MS to c h a r a c t e r i z e 2 5


2

i

0 ^ ^ ^ < ^ C M 2

! c

2

2

C H

NH-C—HH-€H

- { O ) ^ H ^ - ^ C H

\vJ/

* ^ F S V /R\ ^ ^ " ^ 0 X ^ 2

2

c

-

Fe i.

^

2

2

β—CH CH NH~

F i g u r e 1. Average s t r u c t u r e o f segmented p o l y u r e t h a n e c o n t a i n i n g ferrocene units. (Reproduced w i t h p e r m i s s i o n from R e f . 53· C o p y r i g h t 1986 John W i l e y . )

2

-ΚΚ-€Η -0-^ —

Ï

Ρ

S

BPUR2

-fCH-CH —0-^

3

f"

BPUla


_ ο" 2: = >enen s> ta



448

segmented c o p o l y ( e t h e r u r e t h a n e - u r e a ) (PEUU), by i d e n t i f y i n g k e y fragments and r e l a t i n g them t o the b u i l d i n g b l o c k s o f PEUU — p o l y e t h e r s , d i i s o c y n a t e s , and the diamine. R i c h a r d s e t a l . 2 6 have a l s o u t i l i z e d t h i s t e c h n i q u e f o r the s t r u c t u r a l a n a l y s i s o f a p o l y ( e t h e r urethane-urea) (Biomer). G e n e r a l l y , the d e c o m p o s i t i o n o f the macrom o l e c u l a r c h a i n s i s i n i t i a t e d by s c i s s i o n o f the urea bonds f o l l o w e d by s p l i t t i n g o f the urethane bonds T h i s i s f o l l o w e d by the e v a p o r a t i o n o f the p o l y e t h e r b u i l d i n g b l o c k s . 2 5 Based on the above s t u d i e s , the i d e n t i t y o f the d i i s o c y a n a t e component i n BPUla was deduced by the presence o f fragments a t m/z 250 [ m e t h y l e n e - b i s ( 4 ) p h e n y l - i s o c y a n a t e ] (MDI), 224 (4-amino-4 - i s o c y a n a t o - d i p h e n y l m e t h a n e ) , and 198(diamino-diphenylmethane).27 The presence o f the d i a m i n e , as the c h a i n e x t e n d e r was e v i d e n t from the presence o f the fragments m/z 324, a s s i g n a b l e t o l , l - b i s ( $ - i s o - ^ c y a n a t o e t h y l ) f e r r o c e n e , and 298, a s s i g n a b l e t o the s t r u c t u r e 10. f


2

10

The i n t e n s e s i g n a l s b e l o n g i n g t o the i o n s e r i e s m/z 59, 117, 175, 133, 291, 349, e t c . a r e 58 mass u n i t s a p a r t , c o r r e s p o n d i n g t o t h e mass o f the repeat u n i t s o f PPG.26 Thus t h e c o m p o s i t i o n o f BPUla can be regarded as PPG, end-capped w i t h MDI and c h a i n extended by 1_. The MS o f BPUR2 was s i m i l a r . 13

13 C-NMR. The C-NMR spectrum o f BPUR2 i n a c e t o n e - d ^ a l s o p r o v i d e d i n f o r m a t i o n r e g a r d i n g the i n c o r p o r a t i o n o f BHF i n t o the polymer v i a c h a i n e x t e n s i o n . The δ s h i f t s a t 68.8, 69.7, and 85.4 are w i t h i n the range e x p e c t e d f o r c y c l o p e n t a d i e n y l carbons.28 The methylene carbons a d j a c e n t t o the c y c l o p e n t a d i e n y l r i n g s e x h i b i t the r e s o n ances a t δ 72.3 (C-J and 65.7 ( C ) ppm r e s p e c t i v e l y . The a b s o r b ances a t 75.9 and 73.8 ppm can be a s s i g n e d t o the methine and methylene carbons and the δ s h i f t a t 17.8 ppm t o the m e t h y l c a r bons i n the PPG segments. The a r o m a t i c carbons were a s s i g n e d t h e δ s h i f t s 119.2, 129.7, 136.4 and 138.2 ppm and the methylene c a r b o n , b r i d g i n g the benzene r i n g s , 41 ppm.29 The absorbance a t δ 154.3 ppm b e l o n g s t o the c a r b o n y l c a r b o n o f the urethane group. The i n tense s i g n a l s a t 30.2 and 205.9 a r e o f the s o l v e n t a c e t o n e . The 1 3 spectrum o f BPUla was s i m i l a r but o f l e s s e r r e s o l u t i o n owing t o i t s l i m i t e d s o l u b i l i t y i n a c e t o n e . The above s p e c t r a o f BPUR2 i s g i v e n i n F i g u r e 2. a

C



?

n

2

p

p

m

2

?

—0CH CH -

2

0—C—NH- - ^ Q ^ C H - ^ ^ - N H - C - 0 C H C H ,

F i g u r e 2. NMR spectrum o f BPUR2 i n a c e t o n e - d ^ , 2000 s c a n s . (Reproduced w i t h p e r m i s s i o n from R e f . 53. C o p y r i g h t 1986 John W i l e y ) .

—[Ο—CH—CH -}r

CH,


450


C a t i o n i c P o l y m e r i z a t i o n and C o p o l y m e r i z a t i o n cene Monomers

of Isopropenylmetallo-

Only a few examples o f t h e c a t i o n i c p o l y m e r i z a t i o n r e a c t i o n s o f o r g a n o m e t a l l i c monomers have been r e p o r t e d i n t h e l i t e r a t u r e . K u n i t a k e and c o w o r k e r s ^ f i r s t r e p o r t e d t h e c a t i o n i c p o l y m e r i z a t i o n of v i n y l f e r r o c e n e , and Korshak and c o - w o r k e r s ^ p o l y m e r i z e d 1 , 1 diisopropenylferrocene with cationic i n i t i a t o r s . Recently, J a b l o n s k i and C h i s t i f u r t h e r i n v e s t i g a t e d t h e c a t i o n i c p o l y m e r i z a t i o n of 1,1'-diisopropenylferrocene.^ 1

T

1

The Q-e v a l u e s o f v i n y l f e r r o c e n e determined i n t h e f r e e r a d i c a l c o p o l y m e r i z a t i o n s t u d i e s - * have shown t h a t t h e m e t a l l o c e n e group i s s t r o n g l y e l e c t r o n c o n t r i b u t i n g , and i t i s a l s o known t h a t t h e i s o p r o p e n y l group i s s t r o n g l y e l e c t r o n c o n t r i b u t i n g . F u r t h e r m o r e , t h e i s o p r o p e n y l group has s u b s t a n t i a l advantage o v e r t h e v i n y l group i n c a t i o n i c p o l y m e r i z a t i o n r e a c t i o n s , as seen i n a comparison o f t h e r e l a t i v e p o l y m e r i z a b i l i t i e s o f α-methylstyrene and s t y r e n e . F o r these r e a s o n s , and s i n c e we have been a b l e t o s y n t h e s i z e a wide range o f η^-cyclopentadienyl-metal monomers w h i c h c o n t a i n i s o p r o p e n y l units,33 f e l t t h a t these new o r g a n o m e t a l l i c monomers s h o u l d be p o t e n t i a l l y a t t r a c t i v e c a n d i d a t e s f o r polymers prepared by c a t i o n i c i n i t i a t i o n c o n d i t i o n s . As an i n i t i a l s t e p i n our i n v e s t i g a t i o n s i n t h i s u n c h a r t e d a r e a , we s t u d i e d i n some d e t a i l t h e c a t i o n i c p o l y m e r i z a t i o n r e a c t i o n s o f i s o p r o p e n y l f e r r o c e n e ( I F ) i t s e l f . We were p a r t i c u l a r l y i n t e r e s t e d i n d e t e r m i n i n g the e f f e c t o f t h e i n t e r a c t i o n of t h e p r o p a g a t i n g carbenium i o n w i t h t h e f e r r o c e n y l group on t h e r e a c t i v i t y and p o l y m e r i z a b i l i t y o f t h i s monomer and o f t h e r e l a t e d i s o p r o p e n y l m e t a l l o c e n e monomers, whose s t r u c t u r e s are shown below, i n c l u d i n g α-trifluorovinylferrocene (TVF), (η^-isopropenylcyclopentadienyl)dicarbonylnitrosylmolybdenum (IDM), and i t s t r i c a r b o n y l m e t h y l a n a l o g (ITMM)


2

w

e

f 3 -C=CH H

CH ^g^C^CH I 2

H

? 3

3

^ ^ F ^ C=CH I Fe

0

9

2

2

Fe

ψ

J NO

CO

CO (IF)

(TVF) CH

(IDM)

H

^ 3

^r-C=CH

3

g

C=CH

2

Sn CO

I

CO CO

^ UM

Y" 2 CH 3

(ITMM) (DIS)


36.



451

Ferrocene Monomers. A l t h o u g h the i s o p r o p e n y l f e r r o c e n e monomer has been r e p o r t e d p r e v i o u s l y by s e v e r a l groups o f i n v e s t i g a t o r s , 3 4 - 3 7 we were a b l e t o develop a more f a c i l e , dependable, h i g h y i e l d synthes i s f o r t h i s compound, u t i l i z i n g the t h r e e - s t e p p r o c e d u r e shown below:

» ^^C-CH

CHoCOCl,AlCl

^ 7

CH C1 ,O.5h 2

2

(11) Downloaded by UNIV OF OTTAWA on June 16, 2013 | http://pubs.acs.org Publication Date: January 7, 1988 | doi: 10.1021/bk-1988-0360.ch036

±

*

1 ^ ?

f 3 H

3

CH Mgl/THF^^C-OMgl > I CH 0-10°C, 16h ^ ? Q 3

(12, 53%)

(13)

H

?3

Cationic and Condensation Polymerization of Organometallic Monomers

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