I N F R A R E D S P E C T R A , I t Y D R O G E N B O N D S , A N D

C O N F O R M A T I O N S OF 2 - S U B S T I T U T E D O X A - 3 -

P H O S P H O L A N O L D E R I V A T I V E S

R . R . S h a g i d u l l i n , E . P . T r u t n e v a , a n d F . S . M u k h a m e t o v

UDC 543.422.4:541.57:546 . i i : 541.6:547 .I '118

Employing IR spec t roscopy, a compara t ive study was made in the present paper of the in termolecular tiM) and in t ramolecular H bonds {IHB) of oxa-3-phospholanol derivat ives (Table 1) that, depending on the mutual orientation of the P = O and C--OH bonds, a re capable of existing as the cis and t rans i somers [1-3].

The analysis was based on the absorpt ion bands of the stretching vibrations of the OH group of the c r y s - talline phase and in CC14 solution (C -~ n. 0.1-10 -4 mole / l i te r ) . The broad intense bands of VOH , observed in the spec t ra of the crys ta l l ine phase and concentrated solutions of (I)-(XII) in the 3240-3355 cm -1 region, d is - appear when C _< 10 -4 mole / l i t e r . However, for (I)-WHI) the position of the uOH maximum remains constant here , while for (IX)-('XIH) it changes with dilution (C -~ 10-3-n. 10 -4 mole/ l i ter ) (see Table 1).

Consequently, in all of the cases the discussed absorption is associated with the different IM assoc ia - tions va.. ss . According to [1-3], a constancy in the v ~ i ~ values of (I)-(VIII) makes it possible to unequivocally

H assign t~e IM associa tes of the crys ta l l ine phase and solutions to cyclic d imers .

\ / P~O...II.--O

\ C / , , )< O--H...O=P

/ \

Cyclic d imers of the indicated type can be formed only by the cis i somers [1, 2]. Correspondingly, the descr ibed change in the vaSsOH maxima for (IX)- (XIII) indicates a change in the nature of the H associa tes when

f rom the polymeric [~P=0...H--O--]~ to the open dimers [3] and, because of s t ruc tura l going factors, o o r r e -

s p o n d s to the t rans configuration. T hes e resu l t s , in combination with the data given below for (VI)-(XI), make the ass ignment of (V) and (VIII) more p rec i se [1].

With dec rease in the intensity of v~ i ~ (see Table 1) with dilution, new single bands appear in the spectra of solutions of (I)-(XIII) on the side of higher frequencies . The shape and position of these bands a re indepen- dent of the concentration of the solutions, which indicates that they belong to unassociated molecules I- mono, ,v OH P" From a comparison of the spectra, and also the values of the v ~ no for the pairs (I)-(IX), (III)-(X), (Iu etc. , it follows that the bands of the v~ino of the cis forms are shifted more strongly toward the long-wave- regions, and have a greater intensity and halfwidth than the corresponding bands of the trans derivatives. These differences indicate [i, 2] the realization of a comparatively strong spin--spin coupling of [HB ~ P = O. . . H--O-- in the cis isomers.

The small values of the shift AVOH -~ i0 cm -I for the trans isomers relative to , free [3610 [1], see (XIII) v OtI in Table 1] can be caused by a combination of various effects of the substituents on the P atom and the existence of very weak in t ramolecular OH. . . X interaction. Although the presence of such nonlinear H bonds can evoke doubt [2], examples of this can be found in the l i te ra ture [5, 6]. In addition, the nature of the postulated OH. . . X interaction in the t rans oxaphospholanols most probably bears an electrostat ic charac te r , x~thout an ex- pressed direction.

A. E. Arbuzov Institute of Organic and Physical Chemis t ry , Kazan Branch of the Academy of Sciences of the USSR. Translated from Izvest iya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 667-670, March, 1978. Original ar t ic le submitted May 3, 1977.

0568-5230/78/2703-0575S07.50 �9 197,~ Plenum Publishing Corporation 37;5

T A B L E 1. S p e c t r a l C h a r a c t e r i s t i c s of OH Bands of Compounds

O--C(CIIa)2

X - - P ( J C-.CH*

HO CHa

C o m - pound

(1) (Ii)

(IIi) (Iv) (v)

(vl) (vii)

(viii) (ix) (x)

(xi) (xil)

(XIII)

r

[ (C~Hs) zN C~H5

(C2"I3) =N CH=O CtHsO i-CsH,O C=HsS C6H~O (CzI'Is)..N (CH,),N i-CsH,O ~H5 C2H5

rap, *c

125 135 114

1 i ~ 1 2 8

55--57 73---74

126--127 118 140 104 165 82

ass I l vOH, a m " [ . . . . ] mono

crystal- solution [ "OH , line c = i 0 - 3 - I c m -I phase* -- 10 .-". I

mole/liter

3275 3275 3498 3245 3270 35~ 3265 3290 3310 3310 3569 3320 3310 3565 3310 3310 3567 3310 3310 3545 3300 333~5 3572 3230 3598 3240 3335 3600 3245 3355 3599 3210 3330 3596 3160 3310 3610

t a,Oii?" ]- AH, kcal/

3.35 6,0 340 6,0 32O 5,7 300 5,5 300 5,5 300 5,6 300 5,5 290 5,4 275 5,2 275 5,2 255 4,9 280 5,3 3OO ~.5

, ass The vOH bands in the crystalline phase for the studied and previously described [ 1.3]

compounds have two shoulders on the side of the higher and lower frequencies from the maximum. The Av from the maximum is approximately the same for both shoulders and varies from 70 to 95 cm -l. It is probable that these are the combination frequencies vOH

PH... O [4]. UOH • 2y H . . .O is also observed in some cases.

A c o m p a r i s o n of t he m e l t i n g po in t s of t he phospho lano l p a i r s shows tha t t he t r a n s i s o m ~ s~ith t he excep t ion of (IX), have h i g h e r m e l t i n g po in t s than the c o r r e s p o n d i n g c i s d e r i v a t i v e s . I t i s n a t u r a l to r e l a t e th i s to t h e p r o p e r t y of t he m o l e c u l e s of t h e t r a n s f o r m to c r y s t a l l i z e a s t he p o l y m e r i c H a s s o - c i a t e s [6], but the e f fec t s of t he c r y s t a l l i n e pack ing can c a u s e de v i a t i ons f r o m th i s r u l e , l i ke f o r (IX).

A c o m p a r i s o n of t he v a l u e s of t h e , mono f r e q u e n c i e s of t he c i s - t r a n s d e r i v a t i v e s of o x a - 3 - p h o s - "OH /

pho lano l , c o r r e s p o n d i n g to t he s p i n - - s p i n coupl ing of IHB ~ C - - O H . . . O = P ~ o r ~ C- - O H . . . X , wi th the c o r r e s p o n d i n g f r e q u e n c i e s of a c y c l i c ( ~ - h y d r o x y p h o s p h o r y l compounds ( a - H P C ) [3, 7] and the x - r a y s t r u c t u r e da t a fo r (I) and (IX) [2] p e r m i t s mak ing s o m e c o n c l u s i o n s r e g a r d i n g the r e a l i z e d c o n f o r m a t i o n s of (I)-(XII). It was found [2] tha t the d i h e d r a l ang le O = P - - C - - O H in (I) i s equa l to 15 ~ and the P = O and C--OH bonds in t h i s c a s e a r e c l o s e to sh i e ld ing . A p r a c t i c a l l y i d e n t i c a l sh i f t w f r e e _ �9 mono~ f o r (I)- " OH v OH '

(III) permits making a similar conclusion regarding the mutual orientation of the P---O and C--OH groups in (II) [i] and (IIl). _The_ vOHmono increases noticeably when going to (IV)-(VIII) , which is evidently associ-

ated with a decrease in the proton-acceptor ability of the phosphoryl oxygen in (IV)- 0/HI) when compared with (1)-(I~) due to changes in the character of X [8]. Together with this, the v mono of (IV)-(V]]I) are

OH close to the corresponding values of the acyclic analogs [3]. On this basis it may be concluded that the P=O and C--OH bonds in (IV)- (VIII) show greater deviation from shielding than in (1)-(III). A similar corn-

on mono p a r i s of t he Vo. f o r t he t r a n s d e r i v a t i v e s of (IX)-(X/I) , with a d i h e d r a l N - - P - - C - - O H ang le = 33 ~ fo r (IX) [2], indicat~.snthe r e a l i z a t i o n of s k e w e d , o r c l o s e to i t , c o n f o r m a t i o n s in (IX)-(XH).

It s e e m e d of i n t e r e s t to d e t e r m i n e the t h e r m o d y n a m i c c h a r a c t e r i s t i c s of t he H bonds in t he d i m e r i c c o m p l e x e s (I)-(XIII) . The p r e s e n t e d va lue s of the e n tha lp i e s of t he c i s i s o m e r s of (I)-(VIII) w e r e c a l c u - l a ted employ ing the i n t e n s i t y r u l e [9] and w e r e v e r i f i e d fo r (V) and (VI) v ia the t e m p e r a t u r e d e p e n d e n c e of t he l o g a r i t h m of K a s s , with t he c y c l i c c h a r a c t e r of the d i m e r t aken in to accoun t . In both c a s e s t he s c a t - t e r i n g did not exceed 5%. A l i n e a r r e l a t i o n [(--AIt) = 0 . 0 1 2 5 ~ + 1.75; r = 0.99] be tween AvOH = vf~ r e e - v ~ m e r and - -AH i s o b s e r v e d f o r (I)- (VIII) . The - - A H v a l u e s f o r (IX)-(XIID w e r e o b t a i n e d by g r a p h i c a ~ e x - t r ~ o l a t i o n of th i s r e l a t i o n to t he r e g i o n of s m a l l e r AvOH v a l u e s . A c o m p a r i s o n of t he v a l u e s of t h e s h i f t s , and a l s o of t he e n e r g i e s of the H bonds of the p a i r e d c i s - - t r a n s d e r i v a t i v e s , shows tha t t he r i n g d i m e r s a r e r e l a t i v e l y m o r e s t a b l e than the open d i m e r s , which i s in h a r m o n y with [6]. B a s e d on the Av and - -AH

576

va lues , both in the cis and in the t r ans de r iva t ives , the X subst i tuents fall into a s e r i e s that approximate ly co r re sponds to the i r inductive effect ui* [10].

E X P E R I M E N T A L

Compounds (I), (II), (IV)-(X), and (XIII) were synthes ized as descr ibed in [11], while (EI), (XI), and (XII) were obtained by the neut ra l hydrolys is of a lky l -d ia lky lamido ( a , a - d i m e t h y l - 7 - b u t y l ) phosphi tes . The IR s p e c t r a were m eas u red on a UR-20 ins t rument . The exper imenta l p rocedure was analogous to that d e - sc r ibed in [3, 7]

C O N C L U S I O N S

1. The H bonds of 13 oxa-3-phospholanol de r iva t ives were studied. The molecules of the cis i so -

m e r s a r e connected via the H bonds of ~ P - - O . . . H - - O into cyclic d imer s in all of the s t a tes . The c h a r a c -

t e r of the s e l f - a s soc i a t i on of the molecules of the t r ans fo rm changes during the phase t rans i t ion c r y s t a l - - solution f r o m po lymer ic to the open d i m e r s .

2. The monomer i c molecules of the cis de r iva t ives of oxa-3-phospholanol exist in dilute CC14 solu-

tions as c o n f o r m e r s ~vith the i n t r a m o l e c u l a r H bond ~ P - - O . . . H - - O - - C , while in the molecules of the t r ans

i s o m e r s e i ther weak i n t r am o l ecu l a r in te rac t ion of the OH group with the X subst i tuent is obse rved , o r in gene ra l it is absent .

3. The c r i t e r i a for identifying the pai red c i s - - t r a n s i s o m e r s were foand.

L I T E R A T U R E C I T E D

1. R . R . Shagidullin, Yu. Yu. Samitov, F. S. Mukhametov, and N. I. Rizpolozhenski i , Izv. Akad. Nauk SSSR, Ser . K h i m . , 1604 (1972).

2. V . D . Cherep insk i i -Malov , V. G. Andrianov, F. S. Mukhametov, and Yu. G. Struchkov, Izv. Akad. NaukSSSR, Set . K h i m . , 2038 (1974).

3. R . R . Shagidullin and E. P. Tru tneva , Izv. Akad. Nauk SSSR, Ser . Kh im. , 1753 (1 975). 4. M . D . Joes ten and L. I. Schaad, Hydrogen Bonding, Marce l Dekker , I nc . , New York (1974). 5. L . H . Jones , R. M. Badger , and G. E. Moore, J . Chem. Phys . , 19, 1599 (1951). 6. G . C . P imenta l and A. L. McClellan, The Hydrogen Bond [Russian t rans la t ion] , Mir (1964), pp.

226, 39. 7. E . P . Tru tneva and R. R. Shagidullin, Izv. Akad. Nauk SSSR, Ser . K h i m . , 1877 (1975). 8. L . J . Be l lamy, New Data on In f ra red Spect ra of Complex Molecules [Russian t rans la t ion] , Mir

{1971), p. 283. 9. A. u Iogansen, G. A. Kurkchi , and B. V. Rassadin , Zh. Pr ikl . Spek t ro sk . , l_!l , 1054 (1969}.

10. M. Charton, J . Org. C h e m . , 2 9 , 1222 (1964). 11. N . I . Rizpolozhenski i , F. S. Mukhametov, and R. R. Shagidullin, Izv. Akad. Nauk SSSR, Ser. K h im. ,

1121 (1969).

577