A Fairly Stable Crystalline Silanone

Abstract

Silanones 2 substituted by bulky amino- and phosphonium ylide substituents have been synthesized and isolated in crystalline form. Thanks to the steric protection and the strong electron-donating ability of the substituents, silanones 2 are persistent and only slowly dimerizes at room temperature (t_1/2 =0.5 or 5 h). Structural and theoretical analysis of 2 indicate a short Si=O bond (1.533 Å) and an enhanced polarization toward the O atom compared to Me₂ Si=O owing to the strong π-electron donation from the phosphonium ylide substituent.

Keywords: reactive intermediates; silanone; silicon; silylene; ylides.