Synthesis of E-alkenylsilanes with dithienosilole and their electrochemical and optical properties

A series of 2,6-bis(ethenylsilyl)-4,4-diphenyldithienosilole derivatives containing silylene-spacer were prepared by platinum-catalyzed hydrosilylation reaction. All the hydrosilylation proceeded regio- and stereoselectively to give solely β-(E)-adducts. The 2,6-bis(ethenylsilyl)-4,4-diphenyldithienosilole derivatives exhibit intense fluorescence emission and high quantum yields. The shoulder band of 9 in the emission spectrum was explained the intramolecular charge transfer from the electron-donating group (dimethylaminostyryl group) to electron-accepting group (dithienosilole moiety). These optical data are in good agreement with the results of theoretical calculations of model compounds at the level of B3LYP/6-31G(d,p).