d r r - p r r CONJUGATION

OF

IN

ORGANOTIN

AND

Sn-O

Sn-S

BONDS

COMPOUNDS

I P. Gol'dshtein, N. N. Zemlyanskii, E. M. Panov, and

UDC 541.6+ 547.1'3 + 546.811

E. N. Gur'yanova, O. P. Syutkina, K. A. Kocheshkov

An i m p o r t a n t p r o b l e m in the s t r u c t u r a l c h e m i s t r y of o r g a n o m e t a l l i c c o m p o u n d s of the type RnMe 9 (XR)4_n, w h e r e X is O, S, Se, etc., M is Si, Sn, Ge, e t c . , is the p r o b l e m of the M - X bond. The n a t u r e of the i n t e r a c t i o n of the h e t e r o a t o m with the m e t a l a t o m l a r g e l y d e t e r m i n e s the p r o p e r t i e s of s u c h c o m p o u n d s and t h e i r r e a c t i v i t y . In this w o r k , u s i n g o r g a n o t i n c o m p o u n d s containing a l k o x y - and m e r c a p t o - g r o u p s a s an e x a m p l e , an a t t e m p t w a s m a d e to c l a r i f y c e r t a i n q u e s t i o n s p e r t a i n i n g to this p r o b l e m . The Sn--O and S n - S b o n d s evidently a r e not s i m p l e or-bonds, d~ and p r i n t e r a c t i o n on a c c o u n t of the v a c a n t w l e n e e d - o r b i t a l s of the tin a t o m and the u n s h a r e d p a i r s of v a l e n c e e l e c t r o n s of the O or S a t o m s is p o s s i b [ e h e r e . One of the m e t h o d s of evaluating the p a r t i c i p a t i o n of the u n s h a r e d p a i r s of v a l e n c e e l e c t r o n s in the s u p p l e m e n t a r y i n t e r a c t i o n is a study of the d o n o r p r o p e r t i e s of the c o r r e s p o n d i n g h e t e r o a t o m s ~ An i n t e r a c t i o n of the dTr-P~r type in S n - X bonds should s u b s t a n t i a l l y r e d u c e o r e l i m i n a t e the d o n o r p r o p e r t i e s of the h e t e r o a t o m X, as is o b s e r v e d in the c a s e of p - ~ conjugation in m o l e c u l e s of a r o m a t i c o r ~ - u n s a t u r a t e d e t h e r s and sulfides [1, 2]. C o n s i d e r i n g the a f o r e m e n t i o n e d , it m i g h t have b e e n e x p e c t e d that a study o[ the c o o r d i n a t i o n c a p a c i t y of the i n v e s t i g a t e d c o m p o u n d s would give v a l u a b l e i n f o r m a t i o n on the state of rise u n s h a r e d p a i r of e l e c t r o n s of the c o r r e s p o n d i n g h e t e r o a t o m s . In this w o r k , we studied p r o c e s s e s of c o m p l e x f o r m a t i o n in s y s t e m s w h e r e the a c c e p t o r s (A) w e r e stannic e M o r i d e or dibutyltin d i c h l o r i d e , and the d o n o r s (D) w e r e a l k o x y t r i a l k y l t i n , dialkoxyldialkyltin, and a n a l o g o u s c o m p o u n d s containing s u l f u r : RaSnSR and R2Sn(SR)2, by m e t h o d s of c r y o s c o p y , d i e l e c t r o m e t r y [3], and c a l o r i m e t r i c t i t r a t i o n [4]. The f o r m u l a s and b a s i c p a r a m e t e r s of the i n v e s t i g a t e d c o m p o u n d s a r e g i v e n in Table 1. The e x p e r i m e n t a l data indicated that c o m p o u n d s c o n t a i n i n g oxygen and c o m p o u n d s c o n t a i n i n g s u l f u r b e h a v e d i f f e r e n t l y with r e s p e c t to a e c e p t o r s . The f o r m e r give s t a b l e c o m p l e x e s both with SnC14 and with R2SnC12. This is d i s t i n c t l y evident f r o m Fig. 1 ( c u r v e s 1 and 3). The p r e s e n c e of points of inflection at the c o n c e n t r a t i o n r a t i o C D : CA = 1 : 1 is e v i d e n c e of w e a k d i s s o c i a t i o n of the c o m p l e x e s f o r m e d in solution. We had shown e a r l i e r that d o n o r - a c c e p t o r bonds a r e f o r m e d h e r e with p a r t i c i p a t i o n of the oxygen a t o m s of the alkoxy g r o u p s [5]. Table 2 p r e s e n t s the h e a t s of f o r m a t i o n of the c o m p l e x e s , found by the TABLE 1 bp, ~ (p, mm Hg)

Compound

nf

4o "~

o~'~ found

o

,-~a

Z | 2

3 4 5 6 7

(C4H9)aSnSC4H9 (C4H9) 2Sn (SC4H~) 2

/el (C4H9)2Sn\sc4H9 [(CH3)~Sn=Sh* (C4tI9)aSnOCHa (C~Hs)aSnOC~H~ (C4H9)=8n,(OCHah

!

160--162 (2) I58--160 (2.5)

1.4981 1,5238

1.102 100.8!100.9[ 373 1,145 109.9I09,11 411

379 411

--

1,5209

1.225

358

149(rap) 108 (2) 81--82 (13) 150--152 (3)

88.8 87,3

349

= 1.617 ~ = 3.63/ 97.11 98.81 517 1.4746 1.129 r 80.0 79.6 32 l / 1.4680 255 1.4876 1.291 ," 6,578166-~9' 349--466

542 321 251 295

* The m o l e c u l a r r e f r a c t i o n v~as d e t e r m i n e d a c c o r d i n g to the c o n c e n t r a tion d e p e n d e n c e of n and d of solutions in b e n z e n e . L. ](a. K a r p o v P h y s i c o e h e m i c a l Institute. T r a n s l a t e d f r o m I z v e s t i y a A k a d e m i i Nauk SSSR, S e r i y a Khimiche~3kaya, No. 10, pp. 2201-2207, O c t o b e r , 1967. O r i g i n a l a r t i c l e submitted. F e b r u a r y 25, 1967.

2115

TABLE 2

Reaction .

9

mole

~o SllCl4-}- (C4H9) 2Sn (OC4H9)2 ~ SnC14- (C4H9)2S1](OC4H9)2 (C4H9)2S1]C12-]- (C4H9)2Sll(OC}I3)2~ (C~Hg)2SNC12.(C4H9)2Sn(OCtfa) 2 (C~H,)2SnBr2 + (C4H9)2Sn(OCH3)2~ (C4H9)~SnBr._-(C4Hg)2Sn(OCH~)~. (G4H,)2SnCl2+ (C4H9)2Sn(OC4H9}2~ (C4H9)2SnC12.(C41-19)2Sn(OC4119)z (C4H9)2Sr.Cl2+ (C4H~)2Sn(SC4H9)2~ 2 (C4H~)2SnCl(SC4tIg) (C4Hg)2SnBr2 + (C4Hg)2Sn(SC4H9)z~ 2(C4HghSnBr(SC~,H9) SnC14 + C4H90(CH2)2OC4H9~ SnC14.C4H~0(CHJ 20C4H~ SriCl4 + C4H9S(CHJ ~SC~H9~ SnCI~.C4}19S(CHJ 2SC4H~

1

2 3 4

5 6

7 8

33.2"

15.6" 15.4" 14.6" 1.3 1,6 21.9 27.4

* M e a s u r e d e a r l i e r [5].

tO

x/x

,2

2 -~-

m e t h o d of c a l o r i m e t r i c t i t r a t i o n . F r o m a c o m p a r i s o n of the v a l u e s of - A H , p e r t a i n i n g to o x y g e n - c o n t a i n i n g c o m p o u n d s , i t i s e v i d e n t t h a t the d o n o r p r o p e r t i e s of t h e o x y g e n a t o m in a l k o x y c o m p o u n d s of t i n a r e s u b s t a n t i a l l y h i g h e r t h a n in t h e s i m p l e e t h e r s . A m o n g the e t h e r s , t h e m o s t s t a b l e c o m p l e x e s with SnC14 a r e g i v e n b y the e t h e r s of e t h y l e n e g l y c o l R - - O - ( C H 2 ) 2 - O - R . The h e a t of f o r m a t i o n of t h e c o m p l e x SnC14 9 C4H90 9 (CH2)2OCtH9 i s 21.9 k c a l / m o l e , w h i l e the h e a t of f o r m a t i o n of the c o m p l e x SnC14 9 (C4Hg)2Sn(OC4Hg) 2 i s 33.2 k c a l / m o l e .

The i n c r e a s e d d o n o r c a p a c i t y of t h e o x y g e n a t o m in a l k o x y d e r i v a t i v e s of tin in c o m p a r i s o n w i t h e t h e r s i s a l s o i n d i c a t e d by t h e c o m p l e x CDICA f o r m a t i o n w i t h w e a k e r a c c e p t o r s - R2SnC12 and R2SnBr 2 ( s e e T a b l e 2, c o m p o u n d s 2 and 3). The l a t t e r , in c o n t r a s t to SnC14, do n o t g i v e c o m F i g . 1. C a l o r i m e t r i c t i t r a t i o n p l e x e s w i t h e t h e r s , i n c l u d i n g e t h e r s of e t h y l e n e g l y c o l . A s f o r s u l f u r of a s o l u t i o n of (C4Hg)2SnC12 c o n t a i n i n g o r g a n o t i n c o m p o u n d s , it m i g h t h a v e b e e n e x p e c t e d t h a t t h e y in n - h e x a n e : 1) (C4Hg)2Sn. w o u l d b e s t r o n g e r d o n o r s w i t h r e s p e c t to SnC14 and R2SnC12 t h a n t h e c o r (OCH3)2; 2) (C4Hg)2Sn(SC4Hg)2 . responding oxygen compounds, since organic sulfides are more active C r y o s c o p i c t i t r a t i o n of a s o c o m p l e x f o r m e r s w i t h r e s p e c t to t h e s e a c c e p t o r s t h a n a r e e t h e r s [2]. l u t i o n of SnC14 in b e n z e n e ; 3 ) T h i s i s g r a p h i c a l l y d e m o n s t r a t e d by t h e v a l u e s of t h e h e a t s of f o r m a t i o n (CaHg)2Sn(OCH3)2; 4) (C4H9) 2 9 of the c o m p l e x e s SnC14- C4H90(CH2)2OC4H 9 (21.9 k c a l ) and SnC14- C4H9S" Sn(SC4Hg) 2. (CH2)2SC4H 9 [6] (27.4 k c a l ) ( s e e T a b l e 2). H o w e v e r , it w a s found t h a t a l k y l m e r c a p t i d e s of t i n , in c o n t r a s t to o x y g e n c o m p o u n d s , do not g i v e c o m p l e x e s e i t h e r w i t h s t a n n i c c h l o r i d e o r with d i b u t y l t i n d i c h l o r i d e s , C r y o s c o p i c t i t r a t i o n of a s o l u t i o n of SnC14 in b e n z e n e w i t h d i b u t y l t i n d i b u t y l m e r c a p t i d e and t r i a l k y l t i n b u t y l m e r c a p t i d e i n d i c a t e d the a b s e n c e of c o m p l e x f o r m a t i o n ( s e e F i g . 1, c u r v e 4). The m o l e c u l a r w e i g h t c o r r e s p o n d s to t h e m o n o m e r f o r m of t h e s e s u b s t a n c e s ( s e e T a b l e 1). A n a n a l y s i s of the c u r v e s of d i e l e c t r o m e t r i e t i t r a t i o n a l s o i n d i c a t e s the a b s e n c e of c o m p l e x e s in s o l u t i o n . The t h e r m a l e f f e c t s of t h e r e a c t i o n c o m p r i s e only 1 . 3 - 1 . 6 k c a l / m o l e ( s e e T a b l e 2). 0

"-~•215

0.2

0.#

1.0

l.#

/.8

A d i f f e r e n c e in the b e h a v i o r of a l k o x y and m e r c a p t o d e r i v a t i v e s of t i n in s o l u t i o n i s i n d i c a t e d b y t h e r e s u l t s of a d e t e r m i n a t i o n of t h e m o l e c u l a r w e i g h t s of t h e s e c o m p o u n d s a t v a r i o u s c o n c e n t r a t i o n s . The m o l e c u l a r w e i g h t s of s u l f u r - c o n t a i n i n g c o m p o u n d s (see T a b l e 1, c o m p o u n d s 1-3) r e m a i n c o n s t a n t within a b r o a d r a n g e of c o n c e n t r a t i o n s (0.5-50 g / k g ) a n d c o r r e s p o n d to the m o n o m e r f o r m of t h e c o m p o u n d s . The v a l u e s of t h e m o l e c u l a r w e i g h t s of t h e a l k o x y d e r i v a t i v e s v a r y with t h e c o n c e n t r a t i o n , i n d i c a t i n g s u b s t a n t i a l a s s o c i a t i o n of t h e m . The q u e s t i o n a r i s e s of t h e c a u s e s of t h e s e d i f f e r e n c e s . We s h o u l d m e n t i o n t h a t the i n v e s t i g a t e d c o m p o u n d s a r e c l o s e in s t e r i c p a r a m e t e r s , and e v i d e n t l y s t e r i c f a c t o r s a r e not d e t e r m i n i n g h e r e . The b a s i c c a u s e of t h e d i f f e r e n c e in t h e d o n o r p r o p e r t i e s of a l k o x y and m e r c a p t o d e r i v a t i v e s of t i n e v i d e n t l y i s the d i f f e r e n t s t a t e of t h e u n s h a r e d p a i r of e l e c t r o n s of t h e O and S a t o m s in t h e s e c o m p o u n d s . F r o m a c o m p a r i s o n of the d a t a o b t a i n e d , i t c a n b e c o n c l u d e d t h a t in a l k o x y d e r i v a t i v e s of t i n , t h e u n s h a r e d p a i r of e l e c t r o n s of t h e o x y g e n a t o m , r e s p o n s i b l e f o r c o m p l e x f o r m a t i o n , i s f r e e . It is not b o n d e d b y a d a t i v e i n t e r a c t i o n to t h e v a c a n t o r b i t a l s of t h e t i n a t o m . On the c o n t r a r y , a s a r e s u l t of the i n d u c t i v e e f f e c t , t h e r e i s a s h i f t of e l e c t r o n d e n s i t y to the o x y g e n a t o m , and a s a r e s u l t , an i n c r e a s e in i t s d o n o r a c t i v i t y in c o m p a r i son with e t h e r s . The d e c r e a s e in t h e d o n o r c a p a c i t y of s u l f u r a t o m s in t i n a l k y l m e r c a p t i d e s in c o m p a r i s o n w i t h a l k y l s u l f i d e s , i s e v i d e n c e t h a t t h e u n s h a r e d p a i r of e l e c t r o n s of t h e s u l f u r a t o m , p a r t i c i p a t i n g in the f o r m a t i o n of d o n o r - a c c e p t o r b o n d s , i s not f r e e h e r e . It i s b o n d e d to the t i n a t o m b y a d a t i v e i n t e r a c t i o n .

2116

TAB LE 3 iglooi Compmmd

~, m ~

log 6

~,, roll

log

900o ~oog 7~00 8000 58~ 4080 3OO0

3.78 3.96

242 252

3.15 3.43

211

3.91

252

3.40

209 2O8 215 206,5

4.20 4.32 3.18 4.19 3.99

240 246.5

4.10 3.67

(CiII~)~SII(SC4H9) 2

211 211

(C~H~) ~Sn\

(C4H9)aSnSC4H9

/el

\SC~H9 [(CHa)~Sn= Sh ('C4H~)aSnSSn (C4H~)a* (~4H9)~Sn(OCHa) (C4H9)~SnOSn('C4H9) (C,H~) ~Sn (C~H~)~SnCl~ (~C~H~)~Sn(OOCCH~) ('C~H~)~SnCI (OOCCH~)

202

215 210 211

3.72

3.08 3.57

* Literature data [7].

2000

To c o n f i r m this hypothesis, we conducted a s p e c t r o scopic investigation of alkoxy and m e r c a p t o derivatives of 1000 tin. The r e s u l t s a r e cited in Table 3 and in Fig, 2. For c o m o p a r i s o n we took the s p e c t r a of dibutyltin dichloride, dibutyltin ~oo 22o z4o 260 280 300 diaeetate and (chloro)acetate (see Table 3). As can be seen, all the organotin compounds exhibit intense absorption in the Fig. 2. E l e c t r o n i c s p e c t r a of o r g a n o region of 202-212 m # . Sulfur-containing compounds, m o r e ten compounds- 1) (C4H9)2Sn(SC4Hg)2; over, p o s s e s s c h a r a c t e r i s t i c bands at 240-250 rap. Such a 2) (C4Hg):Sn(SC4Hg)C1; 3) (C4H9)3 9 s p e c t r u m with absorption bands at 208 and 246 m~ have been Sn(SC4Ha}; 4) {C4Hg)2SnC12; 5) (C4H9)2 " d e s c r i b e d for [(CtHg)3Sn]2S [7]. The authors explained the Sn(OOCCH2)C1; 6) (CcHg)2Sn(OOCCH3)2; long-wave absorption by the excitation of the e l e c t r o n of the 7) (C4Hg)~Sn(OCH3)2. unshared pair of the sulfur atom to the vacant d - o r b i t a l s of tin. An analogous absorption in the region of 247.5 m~ is obs e r v e d in the s p e c t r u m of (C6Hs)3SnSn(C6Hs)3. The authors of [8] i n t e r p r e t this band f r o m the standpoint of the concept of i n t r a m o l e c u l a r c h a r g e t r a n s f e r . The appearance of a new band, f r o m this standpoint, is a consequence of the fact that the highest occupied orbital of the donor (the phenyl ring) interacts with the lowest unoccupied orbital of the aeceptor (the tin atom). On the b a s i s of the aforementioned, it may be asumed that the nature of the absorption at 247.5 m# for hexaphenyldistannane and in the region of 240-250 m# for sulfur-containing tin compounds is the same, the only c i f f e r e n c e being that in the f i r s t c a s e the donor is the phenyl ring, while in the second the sulfur atom, pot s e s s i n g an unshared pair of valence e l e c t r o n s , plays the role of the donor. No long-wave a b s o r p tion is observed in the electronic s p e c t r a of oxygen-containing tin compounds (Table 3). Thus, a c o m p a r i s o n of the electronic s p e c t r a of analogously c o n s t r u c t e d oxygen- and s u l f u r - c o n t a i n ing organ3tin compounds also gives evidence of the p r e s e n c e of a dative d~-p~ r interaction in the Sn-S bonds and of the absence of such an interaction in the Sn-O bonds. One of the possible factors responsible for this difference is the conditions of overlapping of the interacting orbitals: the 5 d ~ - o r b i t a l s of tin and the 2 p ~ - or 3 p ~ - o r b i t a l s of the oxygen and sulfur atoms. We calculated the overlapping integrals of the c o r r e s p o n d i n g orbitals in the Slater approximation [9]. The p a r a m e t e r s used in the calculation and the r e sults are cited in Table 4. Here r is the i n t e r a t o m i c distance, ~ = z*/n*, where z* and n* are the effective c h a r g e and effective principal quantum n u m b e r , respectively; p = ~/2(r/aH)(~a + ~b), where a H is the Bohr radius; ~ = (~a-~b)/(~a + ~b); S is the overlapping integral. As can be seen (see Table 4), the overlapping integral of 3p~r-5d ~ is substantially g r e a t e r than the overlapping integral of 2 p ~ - 5 d ~ ; m o r e o v e r , the value of the latter is so small that it would be difficult to expect d~-p~ r coupling between the oxygen and tin atoms in this case. On the c o n t r a r y , the value of S ( 3 p ~ 5d v) is evidence of the possibility of dative interaction between the sulfur and tin a t o m s . The data obtained in this work on the nature of the m e t a l - h e t e r o a t o m bond in alkoxy and m e r c a p t o derivatives of tin p e r m i t us to understand and explain the important differences in the chemical p r o p e r t i e s of these compounds. The c h e m i s t r y of organotin compounds is c h a r a c t e r i z e d by an exchange of functional groups of the type R2SaX2 ~ R2SnY2--~2R~Sn (X) (Y)

(1)

2117

TABLE

4 Overlapping orbitals

Bond

2p~--5dn 3p~--5d~

Sn--O Sn--S

7

Fig. 3. IR s p e c t r a of organotin compounds: 1) (C4Hg)2Sn(SC4Hg)C1; 2) (C4Hg)2Sn(SC4Hg)2; 3) (C4Hg)3SnSC4H9.

r

I

~a

~b

2.06 2.27 0.41 2.44 1.82 0.41

a

9

5.2 5.1

I

0.69 0,63

s 0.059 0,144

However, as was shown e a r l i e r [10], organotin compounds r e a c t according to scheme (1) only when they do not enter into a d o n o r a c c e p t o r interaction. The l a t t e r leads to the formation of c o m plexes of the type R2SnX2 ~- I/2SnY2-~ R2SnX2"tI2SnY2

(2)

Alkoxy-substituted organotin compounds, containing a strong e l e c tron donor group, r e a c t with other organotin compounds (SnC14, R2SnC12, R2SnBr2, alkyltin a c r y l a t e s , etc.) according to s c h e m e (2), giving strong complexes, the heats of formation of which c o m p r i s e tens of kilocalories [10].

The sulfur atom in tin m e r c a p t o derivatives does not m a n i fest donor activity as a r e s u l t of the dative interaction. These compounds do not give d o n o r - a c c e p t o r type complexes either with SnC14 o r with R2SnC12. Probably they should r e a c t a c c o r d ing to scheme (i). We investigated the reaction 690 490 ~ cm-~

C4H~)..SnC12q- (C4Hg)~Sn(SC,tHg)~.~ 2 (C4Hg)~.Sn

/

c!

\ SCtH9

The t h e r m a l effect of this reaction is equal to 1.3 k e a l / m o l e . We obtained the same o r d e r of magnitude e a r l i e r [1] for reactions of exchange of functional groups. The compound produced as a r e s u l t of the indicated reaction, (C4Hg)2SnCI(SC4Hg), has not been d e s c r i b e d in the l i t e r a t u r e . We isolated it and m e a s u r e d its m o l e c u l a r weight and r e f r a c t i o n . The s a m e compound, with exactly coinciding constants (see Table 1), was produced by c o u n t e r s y n t h e s i s according to the scheme / C1Sn(CaHg)20Sn(C4H9)2C1Jr 2 CaHgSH-* 2 (C4H~)2Sn X

Cl ~- H20 SC4H9

To c o n f i r m the fact that the product obtained r e p r e s e n t s an individual compound of the indicated c o m position and is not an equimolar mixture of (C4Hg)2SnC12+ (C4Hg)2Sn(SC4Hg)2, we investigated the IR s p e c t r a in the region of 300-600 c m -1 (Fig. 3). In the s p e c t r a of t r i b u t y l - and dibutyl-tin m e r c a p t i d e s , the intense doublet in the region of 338-363 c m -I for the f o r m e r and 342-358 c m -1 for the l a t t e r evidently belongs to the vibrations of Sn-S [11, 12]. In dibutyltin (chloro)butylmercaptide, the corresponding absorption band r e p r e s e n t s a singlet and is shifted into the lower frequency region, 327 e m -~. In the region of the S n - C vibrations, the IR s p e c t r u m of the investigated product also differs f r o m the s p e c t r u m of dibutyltin dichloride. In the s p e c t r u m of (C4Hg)2SnC12, an intense band is observed in the region of 548 c m -1, belonging to the a n t i s y m m e t r i c a l vibrations of S n - C [13]. In the s p e c t r a of (C4Hs)3SnSC4H9 and (C4Hg)~Sn(SC4Hs)2, the band at 548 c m -1 is absent, but intense bands appear in the region of 500 c m -1, which evidently should be assigned to the S n - C vibrations in these compounds. In the s p e c t r u m of (C4Hg)2SnCI(SC4Hg), evidently the band at 508 c m -1 c o r r e s p o n d s to the S n - C vibrations. Thus, the combination of data obtained shows that the interaction of dibutyltin dichloride with dibutyltin dibutylmercaptide leads, as a r e s u l t of exchange of functional groups, to the formation of a compound with the composition (C4Hg)2SnCI(SC4H~). Such a r e a c t i o n in the case of dialkoxy derivatives ends in the formation of the complex (C4Hg)2SnC12 9 (C4Hg)2Sn(OC4Hg)2. EXPERIMENTAL The electronic s p e c t r a were taken in the region of 200-260 m # on the SP-700 s p e c t r o p h o t o m e t e r . n-Hexane or eyclohexane was used as the solvent. The concentration of the solutions was 10 -4 to 10 -5 M. The s p e c t r a were photographed in quartz cuvettes with a l a y e r thickness of 10 ram.

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The IR spectra in the region of 300-600 cm -I were taken on the UR-10 speetrophotometer ia Teflon cuvettes with windows of polyethylene film. The spectra of liquid tin alkylmereaptides were taken in the individual state. The spectrum of dibutyltin dichloride was photographed in the form of a suspension in liquid pel:rolatum. The heats of reaction were determined by calorimetric titration of solutions of (0.05-0.1 M) of the aceeptor [SnCl4, (C4Hg)2SnCI2, etc.] in preliminarily purified and dried n-hexanewith the corresponding alkoxy ~.nd mereapto compounds on the apparatus described earlier [4]. Alkoxy compounds described earlier.

of tin [14] and dimethyltin sulfide [15] were produced

according to the procedures

TrJbutyltin butylmereaptide was produced from hexabutyldistannoxane and butyl mereaptan according to a procedure analogous to that of [15]. Found %: C 51.5, 51.7; H 9.3, 9.4; S 7.2, 7.3; Sn 28.8, 28.9. C16H36S2Sn. Calculated% : C 50.7; H 9.5; S 8.4; Sn 31.3. Dibutyltin dibutylmercaptide was produced by the action of sodium butylmereaptide on dibutyltin dichloride in a mixture of alcohol and benzene [15]. Found %: C 46.8, 46.9; H 9.1, 9.1; Sn 28.9, 28.9. C16H36 ' S2Sn. Ca]eulated %: C 46.7; H 8.8; Sn 28.9. CONCLUSIONS I. The coordination capacity of organotin compounds containing alkoxy and mereapto groups was investigated by the methods of cryoscopic, dielectrometric, and calorimetric titration. Oxygen- and sulfur-containing compounds behave differently with respect to the acceptors SnCl 4 and (C4Hg)2SnCI 2. The former give stable complexes, while the latter do not form complexes. 2. The difference in the donor capacity of the heteroatoms in alkoxy- and mercapto derivatives of tin is explained by the presence of d~r-pv conjugation in the Sn-S bonds and by its absence in Sn-O bonds. This conclusion was confirmed by an investigation of the electronic spectra and by quantum chemical calculations of the overlapping integrals. 3. The interaction of R2SnHal 2 and R2Sn(XR) 2 leads to the formation of complexes R2SnHal 2 .R2Sn(OR)2 in the ca~:e when X = 0, and to the formation of the compound R2Sn(Hal)(SR) in the case when X = S. Dibutyltin (ehloro)butylmercaptide was isolated and characterized. 4. The IR spectra of (C4Hg)3SnSC4Hg, (C4Hg)2Sn(SC4Hg)2, and (C4Hg)2SnCI(C4Hg) were taken in the region of 300-600 em -I. The frequencies of the Sn-S and Sn-O vibrations were assigned. LITERATURE I. 2. 3. 4. 5. 6. 7. 8.

9. I0. ii. 12. 13. 14. 15.

CITED

I. ]?. Gol'dshtein, E. N. Gur'yanova, and K. A. Kocheshkov, DAN SSSR, 144, 569 (1962). I. ~'. Gol'dshtein, E. N. Gur'yanova, ]~. P. Petrov, and A. I. Shatenshtein, Zh. obshch, khimii, 3__6_6 , 1823 (1966). E.N. Gur'yanova and I. P. Gol'dshtein, Zh. obsheh, khimii, 32, 317 (1962). I. ]?. Gol'dshtein, E. N. Gur'yanova, and I. R. Karpovieh, Zh. fiz. khimii, 3_~9,932 (1965). I. 1c'. Gol'dshtein, N. N. Zemlyanskii, O. P. Shamagina, E. N. Gur'yanova, E. M. Panov, N. A. Slovokho~ova, and K. A. Kocheshkov, DAN SSSR, 163, 880 (1965). I. 1~. Gol'dshtein, E. N. Gur'yanova, and K. A. Kocheshkov, DAN SSSR, 161, iii (1965). C.N.N. Cumper, A. Melnikoff, and A. I. Vogel, J. Chem. Soc. A. Inorg., Phys. Theor., 1966, 239. D.N. Hague and R. H. Prince, J. Chem. Soc., 196__.~5,4690. H.H. Jaffe, J. Chem. Phys., 2__ii,258 (1953). N. I{. Zemlyanskii, I. P. Gol'dshtein, E. N. Gur'yanova, O. P. Syutkina, E. IVi. Panov, N. A. SIovokho~:ova, and K. A. Koeheshkov, Izv. AN SSSR, Set. khim., 1967, 728. M. l~ehmidt and H. Schumann, Z. anorgan und allgem. Chem., 325, 130 (1963). H. ~r and M. Schmidt, J. Organometal. Chem., 3, 485 (1965). I.R. Beattie and G. P. McQuillan, J. Chem. Soc., 1963, 1519. G. ~;. Sasin, J. Organ. Chem., 18, 1142 (1953). E. Blake, G. G. Coates, and I. M. Tare, J. Chem. Soc., 1961, 618.

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