First Organosilicon Molecular Antennas

Synthesis of new dendritic and “butterfly”-like oligothiophenesilanes by Suzuki coupling reactions of specially prepared branched precursors is described. Investigation of their optical properties in dilute THF solutions and in solid films revealed that both molecules show an efficient intramolecular energy transfer from the outer bithiophene to the internal terthiophenesilane units. Both experimental and theoretical estimations of the energy transfer efficiency showed the advantages of the more branched dendritic structure. The dendrimer has uniform absorption in the 280−430 nm region and almost quantitative energy transfer due to specific 3-D dendritic architecture.