1,2-dithiolate derivatives of monosilanes and disilanes

The reactions of the chlorosilanes Me3SiCl, Me2SiCl2, MeSiCl3, SiCl4, SiClM e2-SiClMe2 and SiCl2Me-SiCl2Me with ethane-1,2-dithiol and benzene-1,2-dith iol have been investigated. All silicon dithiolates formed have been charac terized by H-1-, C-13- and Si-29-NMR. The formation of five-membered rings SiS2C2 is accompanied by a strong downfield shift of the Si-29-NMR signals. The molecular structures of Me2SiS2(o-C6H4) (6), Si[S-2(o-C6H4)](2) (7) an d [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 obs erved partial planarizations of the SiS4 tetrahedrons in the spiro compound s Si[(SCH2)(2)](2) and 7 are discussed. (C) 2000 Elsevier Science B.V. All rights reserved.