Synthesis and optical properties of ethynylene-linked starburst oligofluorene based on hexahexyltruxene

New monodisperse starburst oligofluorene derivatives, which contain 5,5′,10,10′,15,15′-hexahexyltruxene as the central core linked with oligo(9,9′-dihexylfluorene) as the arms through ethynylene bridge are presented. All these compounds were prepared via Sonogashira reaction. Their molecular structures were confirmed by NMR, MALDI-TOF MS spectrometry and elementary analysis. The fluorescence spectra showed that introduction of ethynylene linker showed that the optical properties of the starburst oligofluorenes were modified. Both the absorption and the fluorescence peaks were found to be red-shifted.