Synthesis of oligo(thienylenevinylenes) substituted with alkoxy groups

Conjugated oligomers based on a combination of thiophene and 3,4-dialkoxyth iophene moieties have been synthesized via the Vilsmeier formylation, Witti g-Honer reaction, and McMurry coupling reaction starting from dimethyl 3, 4 -dihydroxythiophene-2, 5-dicarboxylates. Comparison of the optical and elec trochemical properties shows that the mixed pi -conjugated oligomers of thi ophene and 3,4-dialkoxythiophene produces a decrease of the highest occupie d molecular orbital-lowest unoccupied molecular orbital gap that is attribu ted to the electron-donating property of the alkoxy groups. (C) 2001 John W iley & Sons, Inc.