Synthesis and characterization of Group 14 elements - dithienylsulfur cycloadducts and oligomers

The reactions of various organometallic dichlorides R2MCl2 (R = Bu, Ph; M = Si, Ge, Sn) with 2,2'-dilithio 3,3'-dithienylsulfur were described. They g ave simultaneously cycloadducts and oligomers. The X-ray crystal structure of the heterocycle 3b shows a slightly distorted six-membered ring with the two heteroatoms (sulfur and germanium) in a boat conformation. The molecul ar weights of the oligomers were determined by size exclusion chromatograph y. Starting from metal divalent species, insoluble oligomers were obtained. The presence of bivalent metallic sites in these chains was verified by cy cloaddition reaction with 3,5-di-t-butyl orthoquinone. Electrical studies s how that these non-doped oligomers behave as semi-conductors. (C) 2000 Else vier Science S.A. All rights reserved.