Chemical and electrochemical investigations on the powerful π-electron donor dithiadiazafulvalene:: Isolation, spectroscopic characterization and charge-transfer complexation

A representative of the title system has been accessible by three methods. namely the electrochemical reduction of the corresponding 2-(phenylthio)thiazolium salt, the chemical coupling of the thiazoline-2-selone in the presence of triethyl phosphite and a basic treatment of the 2-unsubstituted thiazolium salt. The last two procedures allow the isolation in a preparative scale of nearly pure dithiadiazafulvalene, which can be characterized by cyclic voltammetry and usual spectroscopic methods. The crystal structure of a 1:2 charge-transfer complex between this excellent π-donor molecule and tetracyanoquinodimethane as acceptor establishes that the dithiadiazafulvalene is in the dicationic state in the complex.