Ammonium salts of silanethiol and silaneselenol

Abstract

Trisilylamine reacts with H₂Y (Y = S or Se) at room temperature, giving (SiH₃)₂Y and solid equimolar adducts of ammonia and SiH₃Y formulated from their i.r. spectra as NH₄⁺(YSiH₃)^–; N-methyldisilylamine and N-dimethylsilylamine react similarly but more rapidly. Reactions of the ammonium salts with Mel, with Me₃SiCl, with GeH₃Br, and with PF₂Br are described. With acetyl chloride, the esters MeC(O,Y)·SiH₃ are formed; n.m.r. spectra indicate that in these compounds there is intramolecular exchange of SiH₃ between O and Y that is rapid at room temperature but slow at temperatures below –50°. When Y = S, the predominant isomer is MeC(:S)·O·SiH₃; when Y = Se, the ratio of isomers CH₃·C(:O)·Se·SiH₃:MeC(:Se)·O·SiH ₃ is ca. 2·5.