1,2-Dithiolate derivatives of monosilanes and disilanes

The reactions of the chlorosilanes Me3SiCl, Me2SiCl2, MeSiCl3, SiCl4, SiClMe2–SiClMe2 and SiCl2Me–SiCl2Me with ethane-1,2-dithiol and benzene-1,2-dithiol have been investigated. All silicon dithiolates formed have been characterized by 1H-, 13C- and 29Si-NMR. The formation of five-membered rings SiS2C2 is accompanied by a strong downfield shift of the 29Si-NMR signals. The molecular structures of Me2SiS2(o-C6H4) (6), Si[S2(o-C6H4)]2 (7) and [MeSiS2(o-C6H4)]2 (11) are reported. The found geometries are compared with the results of DFT calculations at the B3LYP/6-31G* level, and the observed partial planarizations of the SiS4 tetrahedrons in the spiro compounds Si[(SCH2)2]2 (1) and 7 are discussed.