6. J. Sandst rom, J. Phys. Chem., 71, 2318 (1967). 7. T . H . Siddal andW. E. Stewart, J. Phys. Chem., 74, 3580 (1970). 8. E . A . Allan, R. F. Hobson, L. W. Reeves , and K. N. Shaw, J. Am. Chem. Soc., 94, 6604 (1972). 9. L .W. Jackman , T. E. Kawanagh , and R. C. Haddan, Org. Magn. Reson. , 1, 109 (1969).

10. M . L . F i l l eux-Blanchard and A. Durand-Coutur ier , Bull. Soc. Chim. France , 1972, 4710.

V I B R A T I O N A L S P E C T R A A N D S T R U C T U R E O F S O M E

M E T H Y L S E L E N O P H O S P H O N A T E S A N D M E T H Y L

S E L E N O P H O S P H I N A T E S

I . I . V a n d y u k o v a , R. R. S h a g i d u l l i n , a n d I . A. N u r e t d i n o v

UDC 543.422:54i.6:547.1 'i18

The p r e sen t communicat ion is devoted to the r e su l t s of studying compounds ( I ) - ( I I I ) (Table 1). T h e i r IR and Raman spec t r a w e r e obtained in va r ious phase s ta tes , with var ia t ion in the d ie lec t r ic constant of the med ium (e) a n d the t e m p e r a t u r e (T) , and the dipole momen t s w e r e measu red .

An analys is of the s pec t r a d isc losed that a redis t r ibut ion of the in tens i t ies of some of the IR bands and Raman l ines in the s pec t r a of (I) and (II) occurs when e and T a re var ied . A pa r t of them d i sappears on crysta l l izat ion. All of this t e s t i f i e s to the fact that compounds (I) and (II) r e p r e s e n t a mix tu re of at leas t two rotat ional i s o m e r s , which a r e found in t he rmodynamic equil ibrium. A s i m i l a r c lea r ly e x p r e s s e d p ic tu re is not obse rved in the spec t r a of ( I II) , f rom which it follows that it exis ts in one predominant conformation.

The mos t distinct changes in the s pec t r a of (I) and (II) a re obse rved for the doublet in the 450-550 cm -1 region, which, on the ba s i s of the data in [1-3], belongs to vp = Se (see Table 1). The s y m m e t r i c a l contours of the doublet give r eason to a s sume that main ly two c o n f o r m e r s take pa r t in the equi l ibr ium, or that a pa r t of them have coinciding frequencies . In harmony with the redis t r ibut ion of the in tens i t ies of the doublet when going f rom n-hexane solutions to a cetoni t r i le solutions we ass ign the low-frequency component of vp =Se to the l e s s po la r i s o m e r 1, and the h igh-frequency component to the m o r e po l a r i s o m e r 2 (see Table 1). The AH2-1 and AS2-1 values , m e a s u r e d via the t e m p e r a t u r e dependence of the IR bands [4], t es t i fy that energywise i s o m e r 1 is the p r e f e r r e d i s o m e r in (I) , and i s o m e r 2 in (II) . However, the bands of i s o m e r 1 r ema in in both cases on crys ta l l iza t ion.

According to [2, 3, 5, 6], the conformat ions with a shielding of the bonds and a s imultaneous t r a n s - or ientat ion of two alkoxy groups a re improbable . Taking these conclusions into account, the following i so - m e r s ( t rans , gauche or ienta t ion of the O-CH3 group re la t ive to P = Se) mus t be cons idered for (I).

Se Se Se Se II II II fl

b ' o

(a = gauche ' , gauche) (b = gauche, gauche) (c = t r ans , gauche) (d = t r ans , gauche ' ) .

The vp =Se f requencies of i s o m e r s (a) and (b) , and also of (c) and (d ) , should be c lose due to the close p rox imi ty of the k inemat ic in te rac t ion coefficients in the corresponding secu la r equations for the v ibra t ions of the molecules . The exper imenta l difference, in pa r t i cu l a r Avp = Se, i s great . Consequently, i t may be a s - sumed that equil ibrium is es tabl ished between (a) o r (b) with (c) and (or) (d). I s o m e r s (b), (c) , and (d) have the i r m i r r o r antipodes, and consequently the i r entropy in the value of R is In 2 g r e a t e r than for (a) . The ex- pe r imen ta l value of the di f ference in the ent ropies is c lose to zero. As a resul t , i t i s poss ib le to support the s ta tement that compound (I) exis ts as the conformat ional equi l ibr ium of (b) with (c) and (or) (d).

A. E. Arbuzov Insti tute of Organic and Phys ica l Chemis t ry , Kazan Branch of the Academy of Sciences of the USSR. T r a n s l a t e d f rom Izves t iya Akademii Nauk SSSR, Ser iya Khimicheskaya, No. 6, pp. 1390-1393, June, 1976. Original a r t i c le submit ted August 13, 1975.

This material is protected by copyright registered in the name o f Plenum Publishing Corporation. 227 West 1 7th Street, N e w York, N .Y . 10011. No part I B

o f this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, 1 I microfilming, recording or otherwise without written permission o f the publisher. A copy o f this article is available from the publisher for $7.50.

1334

T A B L E 1

pound C o m -

Formula

0)

(II)

(H!)

(iv)

t " ,] [Raffo ofiso- ] I vP=Se l l gO- { (+0,05) ~ ~_~5 z - '

_ _ - - �9 - ( _ o), (+o,5), 'liquid crys-mer] [eal/ Cal/mole

I tal [R-C,H,, CHaC~ raole �9 deg

(CH~O)~P(So)CHa 483 s 523w

CH~OP (Se)(C2Hs)2 450s 498s

CHaOP(Se)(C6Hs)~ 568s (melt.)

(CHaO)sP(Se) [~] .503m [ 557 m~

482 s i 0,90 0,75 [ -- 2 O,iO 0,25 200

15Om: 1 0,50 0,40 --240 2 o15o 216o

566 s [ t ~

t 0,60 0,50 ] --80 56om I 2 Io,4o 0,50

+0,6

--0,4

--0,5

(• D (in cch)

2,97

3,90 3,90(ia benzene)

2,75

The absence in the R a m a n s p e c t r u m of (I) o f c l e a r l y depo la r i zed l ines in the reg ion of the s t r e t ch ing v ib r a t i ons o f the p h o s p h o r u s skele ton (700-1100 c m -1 } i s in a g r e e m e n t with th is choice. The v e c t o r sum of the DM of the bonds [2] i s s m a l l e r f o r (b) than f o r (c) o r (d). On th i s b a s i s i s o m e r 1 in compound (I) can be ident i f ied ~ I h (b) , and i s o m e r 2 can be ident i f ied with (c) and (or) (d). B a s e d on s t e r i c cons ide ra t ions some p r e f e r e n c e can be g iven to the equ i l ib r ium (b) ~- (d). Th i s i n t e r p r e t a t i o n is found to be in a g r e e m e n t with the ru le that , in the absence of spec ia l nonva lence in t e r ac t ions , the f r equency vp = X f o r the t r a n s i s o m e r is h ighe r than the v p =X fo r the gauche (o r c is ) i s o m e r . The l a t t e r fol lows f r o m the expe r imen t a l and ca l cu la - t ion data f o r the v ib ra t i ons o f m o l e c u l e s with analogous f r a g m e n t s [2, 3]. Since also in the c a s e of (II) r e - p l ac ing the m e d i u m leads to a change in the quant i ta t ive ra t io of the i s o m e r s , i .e . , f o r m s with a d i f fe ren t DM take p a r t in the equ i l ib r ium, we come to the conc lus ion that (II) r e p r e s e n t s ma in ly a m i x t u r e of ro ta t iona l i s o m e r s , vrith a g a u c h e - g a u c h e - g a u c h e ( i s o m e r 1) and t r a n s - ( O C t l 3 ) - g a u c h e - g a u c h e o r i en ta t ion of the subs t i - tuen t s on t:~e P a tom r e l a t i v e to the P = Se bond. P r e v i o u s l y [2] we a s c e r t a i n e d fo r the t r i a lky l s e l enophos - pha tes , in p a r t i c u l a r f o r compound (IV) ( see T a b l e 1), the p r e s e n c e of a s i m i l a r con fo rma t iona l equi l ibr ium.

A c c o r d i n g to [5], compo~md (III) in the c r y s t a l l i n e phase has m o l e c u l e s wi th a gauche o r i en ta t ion of the OCH 3 group r e l a t i ve to the P = Se bond. F r o m a c o m p a r i s o n of the f r equenc i e s of the IR and R a m a n s p e c t r a of the solid, mol ten , and d i s so lved in be nz e ne s a m p l e s it fol lows that th is con fo rma t ion is r e t a ined as the p r e d o m i n a n t con fo rm a t i on in all of the ind ica ted s ta tes .

Unfo:rttmately, at th is s tage it i s difficult to u t i l ize the data obta ined in the p r e s e n t r e s e a r c h on the DM of the compounds fo r the eonfo rma t iona l ana lys i s . The absence of i n fo rma t ion on the va lues of ~P=Se in v a r i - ous e n v i r o n m e n t s i n t e r f e r e s with this . F r o m Tab le 1 it follows that # i n c r e a s e s when going f r o m (i) to (II) , and f r o m (]:V) to (I) and (I I ) . S tar t ing wi th the avai lable data, it i s na tu ra l to a s s u m e that th is r e f l e c t s to a c e r t a i n d e g r e e an i n c r e a s e in the coord ina t ion c h a r a c t e r of the P = Se bond when the alkoxy subst i tuent is r e p l a c e d by alkyl.

Fo r (HI) the DM of the P = Se bond was ca lcu la ted by the addit ive s c h e m e f r o m gexpt ( see T a b l e 1 ), the p a r a m e t e r s given in [5], and the va lues # P - O = - 0 . 6 , ~OCH 3 = --1.13, #P-C~I~5 = --1.00 D. It p r o v e d to be equal to 3.79 D,

E X P E R I M E N T A L M E T H O D

The IR and R a m a n s p e c t r a w e r e ob ta ined on UR- i0 (Zeiss) and PHO (Coderg ) s p e c t r o p h o t o m e t e r s . The DM w e r e m e a s u r e d on an IDM i n s t r u m e n t [7]. The r e f r a c t i v e ind ices w e r e d e t e r m i n e d on an tRP-23 i n s t r u - ment .

Compounds (II) and (III) w e r e s y n t h e s i z e d as d e s c r i b e d in [5, 8]. Compound (I) was obta ined in a s i m i - l a r m a n n e r , bp 97-98 ~ (35 r a m ) ; d~ ~ 1.4741; n ~ 1.5133.

CONCLUSIONS

i. Tie IR and Raman spectra of the methyl selenophosphonates and methyl selenophosphinates: (CHaO)2P(Se)CH3, CH3OP(Se) (C2H5)2, and CHaOP(Se) (C6H5) 2 were studied in various phase states and in sol- vents, and with a variation in the temperature. The vibration bands of the P = Se group were assig~aed.

2. A :~hermodynamic equilibrium of at least two steric forms of the molecule was detected in the first two compounds. The isomers arise as the result of one methoxy group rotating from the gauche position with respect to the P = Se bond to the trans position, with a gauche orientation of the other groupings.

1 335

3. The re la t ive amount of the i s o m e r s in the mix tu re and the the rmodynamic p a r a m e t e r s of the equili- b r i um w e r e determined.

4. The s te r ic conditions c rea ted by the two a ry l rad ica l s in the th i rd compound lead to a s tabi l izat ion of one predominant con fo rmer in all of the s ta tes of the compound, with a gauche or ienta t ion of the OCH3 with respec t to the P = Se bond.

1. 2.

3. 4. 5. 6.

7. 8.

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

R. A. Chittenden and L. C. Thomas , Spectrochim. Acta, 20, 1679 (1964). R. R. Shagidullin, I. I. Vandyukova, and I. A. Nuretdinov, and Kh. Kh. Davletshina, Dokl. Akad. Nauk SSSR, 225, 886 (19755. R. R. Shagidullin, I. I. Vandyukova, and I. A. Nuretdinov, Izv. Akad. Nauk SSSR, Ser. Khim., 1976, 801. S. Mizushima, St ructure of Molecules and In terna l Rotation, Academic P r e s s (1954). G. Lepicard , D. de Saint -Giniez-Liebig , A. Laurent , and C. Rera t , Acta Crys ta l logr . , B25, 617 (1969). O. Exner , L. Amist i , and L. Paskun, in monograph " A b s t r a c t s of P a p e r s Del ivered at Fifth All-Union Conference on the Chemis t ry of Organophosphorus Compounds", Moscow [Russian t ransla t ion] , "Nauk~' (1972), p. 256. R. Sh. Nigmatul l in and M. R. Vyaselev, Zavod. Lab., 30, 500 (1964). E. V. Bayandina and I. A. Nuretdinov, Zh. Obshch. Khim., 46, 288 (1976).

M E T H A N O L Y S I S O F 4 - M E T H Y L - 1 , 3 - D I O X A N E

M. G. S a f a r o v , D. L. R a k h m a n k u l o v , V. G. S a f a r o v a , a n d V. D. K o m i s s a r o v

UDC 541.127:542.91:547.841

The alcoholysis of 1 ,3-dioxanes is used to synthesize 1,3-diols , alcohol e thers , and dienic hydrocarbons [1]. The p re sen t pape r is devoted to a study of the products and kinet ics of the indicated reac t ion on the ex- ample of the methanolys i s of 4 - m e t h y l - l , 3 - d i o x a n e in the p r e s e n c e of H2 SO4.

E X P E R I M E N T A L M E T H O D

4-Methy l - l , 3 -d ioxane (MD5, synthesized as descr ibed in [2], was repea ted ly dist i l led ove r Na, bp 114.5~ n~ 1.4165; d 2~ 0.9747. The methanol (MN) was purif ied as descr ibed in [3].

The methanolys i s of the MD was run by heating a mix tu re of 29.3 g of MD, 193.0 g of MN, and 26.7 g of H~SO4 at 60-65~ for 3.5 h. The mix tu re was cooled, neut ra l ized with dry NH3, and fi l tered. Atmospher ic dist i l lat ion through a p r e c i s e f ract ionat ion column (8 theore t ica l plates) gave 158.0 g of MN, 6.1 g of MD, and 16.2 g (93.4%) of methyla l (MA5, bp 42.2~ n ~ 1.3530; d~ ~ 0.8610. Vacuum-dis t i l la t ion of the res idue through a mic roco lumn gave 16.0 g (93.2%5 of 1,3-butanedlol (BD) [4] (bp 92-93 ~ (3 m m ) ; n ~ 1.4408; d~ ~ 1.0039) and 2.0 g (6.6%) of 3 - m e t h y l - 4 , 6 - d i o x a - l - h e p t a n o l (MDH) (bp 67-69 ~ (5 m m ) ; n2~ 1.4220; d 2~ 0.9862).

The reac t ion ra te was studied in t he rmos t a t t ed 3 - m l glass ampuls. At the end of exper iment the ampuls were cooled rapidly to - 1 8 ~ and the mix tu re was neut ra l ized with dry NH~ and then analyzed for the amount of MD and react ion products by GLC ( f lame- ioniza t ion detector , 13% n i t r i l e - s i loxane rubber deposi ted on INZ-600, 50-120 ~ and c a r r i e r gas = helium5. Based on the data of the control exper iments , t r ea tmen t of the react ion mix tu re with ammonia does not affect the analys is resul ts .

D I S C U S S I O N O F R E S U L T S

The main react ion products of MD with methanol a re MA and BD. The indicated products a r e fo rmed in para l l e l in p rac t i ca l ly the same yields; in view of the las t fact, we analyzed for only MD and MA in all of the kinetic exper iments . The typical kinetic curves for the consumption of MD and the accumulat ion of MA are

Inst i tute of Chemis t ry , Bashk i r Branch of the Academy of Sciences of the USSR, Ufa. T rans l a t ed f rom Izves t iya Akademii Nauk SSSR, Ser iya Khimicheskaya, No. 6, pp. 1393-1395, June, 1976. Original a r t ic le sub- mi t ted August 18, 1975.

'This material is protected by copyright registered in the name o / P l e n u m Publishing Corporation, 227 West I Fth Street, N e w York. N. Yr 10011. NO part i

]of this publication may be reproduced, stored DI a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, t [ microfilming, recording or otherwise, without written permission o f the publisher. A copy o f this article is available from the publisher for $ 7. 50.

1336