3,4-DINITROTHIOPHENE AS A CENTRAL UNIT OF QUADRUPOLAR PUSH-PULL-PUSH SYSTEMS

Abstract

3,4-Dinitrothiophene has been utilized as a central acceptor unit in quadrupolar D-π-A-π-D push-pull-push chromophores. Employing cross-coupling and Knoevenagel reactions, nine novel chromophores bearing terminal methoxythiophene donor and systematically extended/varied π-linker were synthesized. Optical properties were studied by electronic absorption spectra. Fundamental optoelectronic properties were investigated by semiempirical PM7 calculations. It was shown that by varying the π-conjugated system the longest-wavelength absorption maxima can be shifted from 341 to 489 nm. The calculated HOMO–LUMO gaps were found within the range of 6.69–7.29 eV, while the second-order molecular polarizabilities can be tuned from 0.038 to 1.578 × 10^–27 esu.