Mechanism of Dimerization of 1,4-Dithiafulvenes into TTF Vinylogues

Mechanism of the oxidative dimerization of DTF (dithiafulvenes) to form TTF vinylogues (tetrathiafulvalenes) has been investigated by cyclic voltammetry at low and high scan rates for a series of substituted DTF. It involves first the formation of the cation radical which couples to form the protonated dication. This dication slowly deprotonates to give the final TTF ( k = 0.5−1 s -1 ). The dimerization rate constant was found to be in the range of k dim = (2−4) × 10 8 L mol -1 s -1 and not vary much with the nature of the substituent.