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 r efluxing chlorobenzene afforded the corresponding substituted oligophenylen evinylenes (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 obs erved for these OPVs depending on the nature of the substituent. The electr on-donating alkoxy substituent shifted the emission to the longer wavelengt h whereas the electron-withdrawing trifluoromethyl group caused a blue shif t in the fluorescence spectra. (C) 2001 Elsevier Science B.V. All rights re served.