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Determination of the molecular structure of gaseous dichloromethylvinylsilane, CH2CHSiMeCl2, by electron diffraction

1994; Elsevier BV; Volume: 318; Linguagem: Inglês

10.1016/0022-2860(93)07919-n

1872-8014

V. A. Naumov, М. Б. Зуев, David W. H. Rankin, Heather E. Robertson,

Analytical Chemistry and Chromatography

The molecular structure and conformation of dichloromethylvinylsilane in the gas phase have been determined by electtron diffraction. A force-field, which reproduced experimental vibrational frequencies, was used to calculate mean-square amplitudes of vibration and shrinkage corrections, so that the rα structure could be determined. At room temperature, 67(19)% of the molecules were in a gauche conformation in which the CCSiC dihedral angle was 104(5)°, while the remaining molecules adopted a conformation in which this angle was 0°. The principal refined parameters were r(CC) 131.9(7) pm, r(SiCl) 204.8(2) pm, ∠CSiCl 108.4(4)° and ∠CSiC 115.6(13)°. The SiC(methyl) and SiC(vinyl) distances were refined as a single parameter, with the difference between them being fixed at 2.3 pm. The SiC(methyl) distance was then 186.0(3) pm. The SiCC angle refined to 124.3(13)° in the gauche conformer, with the angle in the other conformer fixed at 1.2° larger than this.