Synthesis of dithienogermole-containing oligo- and polysilsesquioxanes as luminescent materials.

Dithienogermole (DTG)-containing oligo- and polysilsesquioxanes were prepared by hydrolysis/condensation of DTGs bearing one () or two trialkoxysilyl group(s) (). The reaction of gave a cage-type octasilsesquioxane with eight DTG groups at the edges () as a viscous oil, whereas the reaction of yielded a network polymer () as a self-standing film. showed a photoluminescence (PL) quantum yield (Φ) of 56% in THF. This value was as high as that of (Φ = 58%), in spite of the accumulation of DTG units in the molecule, as characteristics of the POSS structure. The PL of in THF was suppressed by contact with nitrobenzene, showing the potential of for sensing nitroaromatic explosives. Polymer exhibited a relatively low Φ of 2% as a film, but Φ was improved to 38% by copolymerization with trimethoxymethylsilane. was also copolymerized with a trimethoxysilyl-substituted carbazole derivative () to provide polysilsesquioxanes with DTG and carbazole units, which showed efficient photo-energy transfer from carbazole to DTG in the films. Similar copolymerization of with in the presence of poly(9-vinylcarbazole) provided a composite material with hole-transporting electroluminescence properties, applicable in multi-layered organic light emitting diodes.