1924 Inorganic Chemistry, Vol. 11, No. 8, 1972
R. L. MITAL,R. D. GOYAL, AND R. R. GUPTA CONTRIBUTION FROM THE CHEMISTRY DEPARTMENT, RAJASTHAN UNIVERSITY, JAIPUR-4, INDIA
Studies on Diamagnetic Susceptibility of Silicon Compounds Containing Sulfur-Silicon and Sulfur-Silicon-Nitrogen Bonds BY R. L. MITAL,
R.D. GOYAL, ASD R. R. GUPTA*
Received December 20, 1971 Diamagnetic susceptibilities of four &substituted 2-aminobenzenethiols, five alkylthiotrimethylsilanes, and five heterocyclic derivatives containing S-Si-iY linkages are reported. x ~ in i alkylthiotrimethylsilanes has been obtained graphically and this value of xsi agrees with that reported for silicon compounds containing all the four Si-C bonds. xsiin compounds containing one S-Si-S linkage is almost the same as that of silicon compounds containing one Si-iY bond. x ~ ini compounds containing two -S-Si-?j- bonds agrees with the value of xsi for compounds containing two Si-K bonds and differs from the xsl value for compounds containing one -S-Si-N- bond I t is reported that the replacement of a C-Si bond by a S-Si bond does not have any effect on x8.
I n recent years diamagnetic studies have been proven to be useful in the interpretation of structural silicon chemistry.l-j No studies appear to have been made on silicon compounds containing Si-S bonds and, therefore, it was considered worthwhile to investigate the diamagnetic properties of a number of thiosilane compounds.
TABLE I DIAMAGNETIC SUSCEPTIBILITY DATA Compd (CHdqSiR, R = C L H ~ iz-CaH7 i-C3H7 ?z-CaHg teri-CdHs N
X ala
20. 75b 20 75*
153 7 1 170 26 183 29 199,37
17 39 17.52 17.47 17.45
114.44
19.38
20 756
N
Experimental Section Five alkylthiotrimethylsilane compounds, (CH3)aSiSR (R = CHp, n-C3H7, i-CsH7, n-CaHg, tert-CaHg), were prepared by the method given by Abel.6 The complex
XSi
102.61 114.09 115.11 125.73 126.65
R,
c1 Br
Diamagnetic contribution of
was prepared by the method given by Wieber.7,8 Four compounds
-?
R,
were prepared by G ~ y a l . Diamagnetic ~ susceptibilities of four 5-substituted o-aminobenzenethiols 75.94 85.15 91.69 99.74
Rl &NH2 and ten silicon compounds containing Si-S bonds have been measured with a sensitive Gouy b a l a n ~ e . ~The order of the Gouy force is h 0 . 0 5 mg. Measured XII values are summarized in the Table I.
Discussion A plot of XRI against n for the series (CH3)&3iS[(CH2)%H]has been made. The plot is linear with an ordinate intercept of 80.0 which shows that X(CH3)aSiS[(CHr)oHl =
3XCHa
f
XSi
+
XS
f
XH
&68 16 76.37 82.91 90.96
a All the XII values are X10-6 cgsu throughout the paper. Determined from the plot of XAI against TZ in the series (CHB)&S[(CHz)nH].
x s i in heterocyclic compounds of silicon has been calculated by subtracting the diamagnetic contributions of the CH3 group and of
=
80.0. Using XH = 2.0,5 XCH> = 13.45,j and xs = 16.90,j xsi has been calculated to be 20.75. This value of x s i is comparable that reported ( X S ~ = 20.6-21.0)5 for silicon compounds in which the silicon atom is coordinated to four carbon atoms. (1) R. L. Mital and R . R. Gupta, J . A m e r . Chein. Soc., 91,4664 (1969). (2) R. D. Goyal, R. R. Gupta, and R. L. Mital, J . P h y s . C h e m . , in press. (3) E. W. Abel, R. P. Bush, C. R. Jenkins, and T. Zobel, Tvans. F a v a d e y SOL.,60, 1214 (1964). (4) R. R. Gupta, Ph.D. Thesis, Rajasthan University, Jaipur, 1968. (5) R. D. Goyal, Ph.D. Thesis, Rajasthan University, JaiFUr, 1972. (6) E. W. Abel, J . C h e m . SOL., 4406 (1960). (7) W.Wieber and M. Schmidt, 2. Natuvfovsch. B , 18, 849 (1963). (8) W. Wieber and A I . Schmidt, Angew. Chem., 1nt. E d . Engl., 3, 657 (1964).
from XRI of the corresponding compounds. The diamagnetic contribution of
Ri
hNH-
has been calculated by subtracting and for an S-H bond from xlr of
XH
for an N-H bond
p-SILYLAND p-GERMYLCARBORANES
Inorganic Chemistry, Vol. 11, No. 8, 1972
SH
1925
is 19.38 and in
R,' as suggested by H a b e r d i t ~ l . ~ x s i in
is 17.39-17.52. x s i = 19.38 is comparable with x s i = 19.40 for the series R3-Si-N- and x s i = 17.39-17.52 is comparable with x s i = 17.40 for the compounds conN taining the linkage R2-Si60%, but substantially less of the silyl and germyl derivatives have been isolated by this method. However, an alternative route which utilizes the lithium salt has given (5) Related studies involving the C,C'-(CHa)zCzBaH6- ion have been recently reported by C. G. Savory and M . G. H. Wallbridge, International Meeting on Boron Compounds, Prague, Czechoslovakia, June 1971, Abstract No. 17; see also C. G. Savory and M. G. H . Wallbridge, J . Chem. SOC. A , 622 (1971). The bridged trimethylsilyl and trimethylgermyl r-(CHs)sM-C,C'-(CHs)zCzBaHs species reported by these workers were not observed t o isomerize a t 2 5 O ; behavior a t higher temperatures was evidently not studied. (6) (a) D. F. Gaines and T . V. Iorns, J . Amer. Chem. Soc., S O , 6617 (1968); (b) D. F. Gaines and T. V. Iorns, ibid., 89, 4249 (1967). (7) T. Onak and G. B. Dunks, Inovg. Chem., 5 , 439 (1966).
