Chemical and Electrochemical Investigations on the Powerful (pi)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 2unsubstituted 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 (pi)donor molecule and tetracyanoquinodimethane as acceptor establishes that the dithiadiazafulvalene is in the dicationic state in the complex.