Syntheses and spectroscopic studies of spirobifluorene-bridged bipolar systems; photoinduced electron transfer reactions.

Some 9,9'-spirobifluorene-bridged bipolar systems 1-3 containing 1,3,4-oxadiazole-conjugated oligoaryl and triarylamine moieties have been synthesized, in which 1 exhibits remarkable solvent-polarity dependent fluorescence properties due to a highly efficient photoinduced electron transfer reaction.