ELECTROCHEMICAL SYNTHESIS OF BIS(2-THIENYL)SILANES, 2-THIENYLCHLOROSILANES, BIS[5-(2-BROMOTHIENYL)]SILANES, AND 5-(2-BROMOTHIENYL) DIMETHYLCHLOROSILANE, PRECURSORS OF POLY[(SILANYLENE)THIOPHENE]S

Bis(2-thienyl)silanes and bis[5-(2-bromothienyl)]silanes were synthesi zed by electrochemical reduction of monohalothiophenes (Br,CI) and 2,5 -dibromothiophene respectively in the presence of a dichlorosilane in THF or DME, using an undivided cell, a sacrificial Mg or Al anode, a c onstant current density and tetrabutylammonium bromide as the supporti ng electrolyte. In addition, when dichlorosilanes were used in large e xcess, halothiophenes underwent solely a monocoupling reaction leading selectively to thienylchlorosilanes, which reveals the versatility of the electrochemical method.