Nanosized, starlike silicon compounds. Synthesis and optical properties oftris[(tert-butyldimethylsilyl)oligothienylenedimethylsilyl]methylsilanes

Starlike molecules with arms consisting of a tert-butyldimethylsilyloligoth ienylenedimethylsilyl unit, MeSi[SiMe2(T)(n)SiMe2(t-Bu)](3) (7-11; n = 2-6, T = thienylene) were prepared by the reactions of tris(chlorodimethylsilyl )methylsilane, which was chosen as a core, with the tert-butyldimethylsilyl -substituted lithiooligothienylenes used for construction of the arms. UV-v isible absorption and fluorescence properties of 7-11 have been studied in a dioxane solution. The molecules 7-11 showed high fluorescence quantum yie lds with respect to the corresponding oligothiophenes. Compounds 7 and 8 re vealed longer lifetimes than those of bi- and terthiophene. The results of X-ray crystallographic analysis of the bromo derivative 12 are described. T he density functional theoretical calculations were also carried out to com pare the geometrical structures and the excitation energies with the availa ble experimental data.