B R I E F C O M M U N I C A T I O N S

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

2 - S U B S T I T U T E D 3 - O X A P H O S P H O L A N O L S B Y T H E

M E T H O D OF H B O N D S

R. R. S h a g i d u l l i n , A . V . C h e r n o v a , F . S. M u k h a m e t o v , a n d N. I . R i z p o l o z h e n s k i i

UDC 539.124:547.1 '118

:541.57:546.11

In a number of cases the hydrogen bond can be a unique indicator of the electronic state of the atoms in molecules [1-3]. As a continuation of our studies on the electronic structure of phosphorus-containing compounds [4-6] it s eemed interesting to us to appIy this method to the 2-substituted 3-oxaphospholanols (Table 1). As was shown in [11, 12], these compounds can exist as the trans- and c i s - i s o m e r s , in which connection an intramolecular hydrogen bond is real ized in both cases between the OH group and the X sub- stituent in the t r a n s - i s o m e r , and the phosphoryl group in the c i s - i s o m e r .

In Table 1 are given the OH frequencies vOH in the IH spectra of dilute solutions of the investigated compounds in CC14, which were measured more carefully than in [11, 12], and also the Av, the integral intensities (A), and the half-widths (APl/2) of these bands. The general tendency for the intensity A to in- crease and the vOH bands to broaden with increase in Av is in agreement with the previously made conclu- sions regarding the presence of an H bond [11, 12]. It is poss ible to as sume that the order in the arrange- ment of the investigated compounds on the basis of the value of Av is determined by the electronic prop- erties of the X substituents in the t r a n s - i s o m e r s , or of the phosphoryl group in the c i s - i s o m e r s . This assumption is valid under the additional condition that the relative position of the proton donors and a c c e p - tors in the compared compounds is maintained constant. This requirement should be fulfilled for the t r a n s - i s o m e r s , s ince the van der Waals radii of the C, N, and O atoms and the lengths of the P - C , P - N , and P - O bonds do not differ essential ly , while the structure of the ring containing the hydrogen bridge is more or l e s s rigid because of the oxaphospholane ring.

In Table 1 are also given the values of Av for some c i s -2 -der ivat ives of cyclopentanol [7]. A de- crease of Av in the oxaphospholanols when compared with the latter can be due to the distance between the

TABLE 1. Parameters of IR Spectra for 2-Substituted Derivatives of 3-Oxaphospholanol and c i s -2 -Der iva t ives of Cyclopentanol, and of Methanol + Base and Phenol + Base

isomo I

m

o9

O--C (CHs)~ OH \\\,. \ \ C CH, ~ / \ X / \

CHs OH

AvOH ' A~, i A-ol/~, c m - 1 Crn- C1YI "1

(gzHi),N CeH~ - , C~HsO C6H~O " (C,H6),N cis CeH~

* T h e f r e q u e n c y for t r a n s - 1 ,

3608 l 28 3592 1~ 30 3586 22 t6 3564 44 36 3563 45 29 3490 tt8 68 348t t27 80

A.tO-4,.1 l i t e r , M : Crr1-2,

0,9 0,9 t,0 t,2 1,2 1,5 t,5

.A-o, zm-l[71 *

Methanol Base -D+base

A-O, CiYl" I'[81

n-C,H~0 240 t ~ C~H6 42 (CaHs)*O 96 60 CeH6OCHa 94 -- (C*H6)~N 289

2 - c y c l o p e n t a d i o l w a s t a k e n as t h e f r e e [7]. uOH

Phenol + base

Zk~, ClTI "I

0 47 [9]

277 [9]

8t~-[t0] J

A. E. Arbuzov Institute of Organic and Physical Chemistry, Academy of Sciences of the USSR. Translated from Izvest iya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2585-2587, November, 1972. Original art ic le submitted July 5, 1971.

�9 1973 Consultants Bureau, a division of Plenum Publishing Corporation, 227 West 17th Street, New York, N. Y. 10011. All rights reserved. This article cannot be reproduced ]'or any purpose whatsoever without permission of the publisher. A copy of this article is available from the publisher for $15.00.

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H - 2,zeX % ~o

Z,~'SA ""--.._ o

"----i}7 Fig. 1. O - O dis tance (A) in analogous der iva t ives : a) 2-subs t i tu ted 3-oxaphospholanol ( t r an s - i somer) [12]; b) c i s -2 -cyc lopen tano l [13].

/112, CHI " I

25 g ~87

2 z, # 2, g

Fig. 2. Relation between A~ for t r a n s - i s o m e r s of 2-subs t i tu ted 3 -oxaphos - pholanols and the 7r con- stant of the phosphoryl shift of subst i tuent X.

react ing groups (Fig. 1), as well as the resu l t of a change in the e lec t ron densi ty of the accep to r under the influence of the adjacent phosphorus a tom. The fact that the l a t t e r is t rue is convincingly demons t ra t ed by the change in Av for the (C2H5)N grouping f rom the max imum in the s e r i e s of c i s - 2 - d e r i - vat ives of cyelopentanol to near ly the min imum in the s e r i e s of 2-subs t i tu ted oxaphospholanols . If the deciding fac tor in the compared s e r i e s was the di f - f e rence in the d is tance between the donor and the accep to r (see Fig. 1), then the o r d e r of change in A~ obse rved for the cyclopentanol de r iva t ives would a lso b e re ta ined in the oxaphospholanol s e r i e s [8]. The dis t inct ive fea tu res for the fo rmat ion of the i n t r amoleeu la r H bonds in the eyelopentanol d e r i v a - t ives have no effect on the o r d e r of a r r a n g e m e n t of the d i scussed subst i tuents according to the AP. In the fo rmat ion of the in te rmolecu la r hydrogen bond when methanol -D and phenol a r e reac ted with var ious bases (see TabZe 15 the ni t rogen a tom in t r i e thy lamine , the s a m e as in the cor responding cyelopen- tanol der iva t ive , mani fes t s the max imum aceep to r capaci ty , and the highest Av co r re sponds to it in the d i scussed s e r i e s .

As a resul t , when the diethylamino group p roves to be at tached to the phosphorus a tom, then judging by the value of Au, the e lec t ron densi ty on the N a tom d e c r e a s e s sharply . It is difficult to explain the de- sc r ibed fact as being due to anything e lse than a par t i a l shift of the unshared e lec t ron pa i r of ni t rogen a tom to phosphorus , This conclusion is in a g r e e m e n t with the data of o ther methods [14-16].

It is interest ing to mention that the AUOH in the phospholanols d isplays a co r re la t ion with the ~r con- s tants of the phosphoryl shift [17] (Fig. 2}. This also tes t i f ies to a connection between APOH and the e lec - t ronic effects.

EXPERIMENTAL METHOD

The synthesis of the investigated compounds was described in [12]. IR spectra were taken on a

UR-10 instrument. Phosphorus pentoxide was placed [n the cell section of the instrument in order to ex-

clude the absorption of water vapor. CCI 4 was used as the solvent. The concentration of the solutions was

0.3-1 �9 10 -4 M/liter. The cell thickness was 140.03 ram. In order to obtain an accurate value of the fre-

quency the necessary region of the spectrum was recorded at a slow rate under the conditions of 32, : 32 : 50

:4. Here the scattering in the values of the frequency did not exceed ~0.5 cm -I. The integral intensities A

were calculated by the Johannsen method.

The authors express their gratitude to R. ]3. Nigmatullin for participating in the experiment.

C ON C L U S I O N S

I. The adjacency of the P atom causes a change in the aceeptor capacity of the diethylamino group

toward a proton.

2. A change in the acceptor capacity is associated with a delocalization of the electron cloud of the

substituent attached to the P atom.

1, 2.

LITERATURE CITED

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3. I. Grundy and L. J. Morris , Spectrochim. Acta, 20, 695 (1964). 4. R . R . Shagidullin, A. V. Chernova, E. A. Ishmaeva, and A. N. Pudovik, Izv. Akad. Nauk SSSR,

Ser. Khim., 1123 (1966); Dokl. Akad. Nauk SSSR, 173, 135 (1967). 5. R . R . Shagidullin and A. V. Chernova, Izv. Akad. Nauk SSSR, Ser. I/him., 183 (1971). 6. R . R . Shagidullin, A. V. Chernova, V. S. Galeev, and Ya. A. Levin, Izv. Akad. Nauk SSSR, Ser.

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13. K.W. Buck, A. B. Foster, A. Labib, and J. M. Webber, J. Chem. Soc., 2846 (1964). 14. D. Imbery and H. Eriebolin, Z. Naturforsch., 236, 759 (1968). 15. Yu. P. Egorov, Yu. A. Nuzhina, V. A. Shokol, and G. I. Derkach, Zh. Prikl. Spektr., 11, 515

(1969). 16. H. Goldwhite and D. G. Rowsell, J. Chem. Soc., D, 713 (1969). 17. L . C . Thomas and R. A. Chittenden, Spectrochim. Acta, 20, 467 (1964).

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