Aromatic-quinonoid copolymers

Tanaka, S. and Y. Yamashita. 1995. Syntheses of narrow band gap heterocyclic copolymers of aromatic-donor and quinonoid-acceptor units. Synth Met 69 599. 

Table 7.6 Bandgaps (in eV) of A-Q copolymers formed with aromatic thiophene units and ITN, ITA and ITT quinonoid units...

Copolymers of isothianaphthene and thiophene have been the subject of calculations, one of the ideas being that the isothianaphthene would prefer the quinonoid structure whereas the thiophene would prefer the aromatic structure and this could give rise to a lower band gap situation. The calculated bandgaps for 32, 33, and 34 [using the Longuet-Higgins-Salem (LHS) Hamilton-... 

A number of copolymers containing two thiophene rings and one benzo[c]thiophene or a derivative of benzo-[c]thiophene in the repeat unit have been reported. The rationale was to combine a unit that prefers the quinonoid structure in a polymer with thiophenes that prefer the aromatic form in order to form a low band gap polymer. Lorey and Cava [74] prepared copolymer 35, poly-(benzo[c]thiophene-fl//-bithiophene) by the route shown in Scheme 10, and this same polymer was prepared independently by Musmanni and Ferraris [75] and by Bauerle... 

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