Silicon−Fluorine and Silicon−Carbon Bond Cleavage in Organofluorosilicates:  A Molecular Orbital Study

• Published in: Inorganic chemistry Vol. 36; no. 3; pp. 392 - 395
• Main Authors: Ou, Xiaobo, Janzen, Alexander F
• Format: Journal Article
• Language: English
• Published: American Chemical Society 29.01.1997
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic940888q

The mechanism of silicon−fluorine and silicon−carbon bond cleavage in organofluorosilanes and -silicates is analyzed with the aid of molecular orbital calculations. The optimized geometries of reactants and intermediates are calculated, and these calculations support the view that cleavage of Si−F bonds occurs by way of fluorine-bridged Si--F--Si intermediates. Cleavage of a Si−C bond in PhSiF3 takes place in the presence of fluoride ion and oxidizing agents, and the calculations are in agreement with the formation of PhSiF4 - and PhSiF5 2-, followed by oxidation to a radical anion PhSiF5 •-. The latter species, however, is predicted to decompose rapidly to give anionic SiF5 -, and phenyl radicals. These calculations and the proposed mechanisms of bond cleavage are in agreement with experimental data, where available.