Quinoid oligothiophenes

G. Zotti, S. Zecchin, B. Vercelli, A. Berlin, J. Casado, V. Hernandez, R. P. Ortiz, J. T. L6pez Navarrete, E. Orti, P. M. Viruela and B. Milian, Magnetic and conductive properties of quinoidal oligothiophenes, Chem. Mater.,... 

T. Takahashi, K. Matsuoka, K. Takimiya, T. Otsubo and Y. Aso, Extensive quinoidal oligothiophenes with dicyanomethylene groups at terminal positions as highly amphoteric redox molecules, J. Am. Chem. Soc., 127, 8928-8929 (2005). 

We have reviewed the calculations related to the most important properties of thiophene-containing materials, such as the HOMO-LUMO gap (or bandgap for polymers), twisting, the effect of substitution, the nature of charge carriers and IR, Raman and UV-Vis spectra. In addition, promising new classes of thiophene type compounds, such as quinoid oligothiophenes and cyclic oligothiophenes, have been reviewed. This review covers the literature up to mid-2007. 

A series of new quinodimethane-substituted terthiophene and quaterthiophene oligomers (Chart 8.17 and 8.19) were investigated for comparison with a previously studied quinoid oligothiophene that demonstrated high mobilities and ambipolar transport behavior in thin-film transistor devices [103]. Each new quinoidal thiophene derivative shows a reversible one-electron oxidation between 0.85 and 1.32 V, a quasi-reversible one electron second oxidation between 1.37 and 1.96 V and a reversible two-electron reduction between - 0.05 and - 0.23 V. The UV-Vis-NIR spectrum of each compound in solution is dominated by an intense (s = 100000 cm ) low-energy jt-jt transition that has a kmax ranging... 

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