Electroreductive synthesis of oligosilanes and polysilanes with ordered sequences

The stepwise elongation of Si-Si or Si-Ge chain was achieved by the electro reductive cross-coupling reaction of chlorohydrosilanes with dichlorooligos ilanes using magnesium electrodes. The electroreductive cross-coupling reac tion of chlorodimethylsilane (1) with dichlorodiphenylsilane (2) or dichlor odiphenylgermane (4), for instance, gave 1,2-dihydro-1,1,3,3-tetramethyl-2, 2-diphenyltrisilane (3) or bis(hydrodimethylsilyl)germane (5) in good yield . Compounds 3 and 5 were readily transformed to the corresponding 1,3-dichl orotrisilane (6) and bis(chlorosilyl)germane (7), respectively. The electro reductive polymerization of the resulting dichlorooligosilanes using magnes ium electrodes in tetrahydrofuran was successfully applied to the synthesis of sequence-ordered polysilanes. (C) 2000 Elsevier Science S.A. All rights reserved.