Novel electron acceptors containing thiadiazole and thiophene units

A tetracyanodiphenoquinodimethane (TCNDQ) analog containing fused thiadiazole rings is a stronger electron acceptor than tetracyanoquinodimethane (TCNQ). The single crystals of this TCNDQ analog were found to exhibit semiconductive behaviors as a single component whose structures were revealed by X-ray structure analysis. The anion radical salts with Et4N and Me4P ions were obtained as single crystals by electrochemical reduction. They are 1:1 salts and showed semiconductive behaviors. The structures include tape-like networks formed by S–N contacts. Furthermore, one of the benzothiadiazole rings was replaced with a thiophene unit to give new π-extended quinonoid acceptors which are highly polarized and exhibit their absorption maxima above 500 nm.