W(CO)6-Mediated desulfuroligomerization of bis-dithioacetals. New synthesis of substituted oligo(phenylene–vinylenes)

Treatment of bisdithioacetals of 1,4-diaroylbenzenes (4) with W(CO)6 in refluxing chlorobenzene afforded the corresponding substituted oligophenylenevinylenes (OPVs) (5). Average molecular weights determined by GPC indicate that OPVs 5 have 5–13 repetitive substituted phenylenevinylene units with narrow polydispersities. Emission in the blue–green to green region was observed for these OPVs depending on the nature of the substituent. The electron-donating alkoxy substituent shifted the emission to the longer wavelength whereas the electron-withdrawing trifluoromethyl group caused a blue shift in the fluorescence spectra.