Norifumi Kobayashi

Synthesis of dithienosilole-based highly photoluminescent donor–acceptor type compounds

Highly photoluminescent acceptor-donor-acceptor (A-D-A) and donor-acceptor (D-A) type compounds with a dithienosilole unit as the donor and perfluorotolyl or dimesitylboryl group(s) as the acceptor were prepared by the reaction of lithiated dithienosilole derivatives with perfluorotoluene or fluorodimesitylborane, respectively. The resulting A-D-A and D-A type compounds showed red-shifted UV absorption and PL bands compared to those of simple dithienosiloles having no acceptor units, reported previously, and were highly photoluminescent in the solid state as well as in solution. Solvatochromic behaviour that would arise from the intramolecular donor-acceptor interaction were observed for the D-A type compounds with respect to the UV absorption and PL spectra. In addition, it was found that bis(dimesitylboryl)dithienosilole and (dimesitylboryl)(methylthio)dithienosilole responded to coexisting fluoride anions, leading to clear UV absorption and PL spectral changes in solutions.

Distibylation of Acetylenes with Ph2Sb–SbPh2: Synthesis, Crystal Structures and Phosphorescence Properties of Bis(diphenylstibyl)ethenes

Abstract Treatment of tetraphenyldistibine (1) with terminal arylacetylenes, XC6H5C≡CH (2a-c, X=H, F, OMe), gave the corresponding anti-addition products (E)-aryl-1,2-bis(diphenylstibyl)ethenes 3a-c in 11 - 17% yields. A similar reaction of 1 with 1,4-diphenylbutadiyne provided (E)-1,4-diphenyl- 1,2-bis(diphenylstibyl)but-1-en-3-yne (3d) in 28% yield. X-Ray diffraction studies on crystals of 3a, 3b and 3d revealed a congested configuration around the ethylene core. The optical properties of the adducts 3a-d were examined by measuring UV absorption and photoluminescence spectra. Interestingly, 3d showed phosphorescence in the solid state, which was enhanced at low temperature.