Synthesis and electrical conductivities of charge-transfer complexes of bis(vinylenedithio)tetrathiafulvalene and its methyl derivatives with strong acceptors

Abstract

Charge-transfer complexes of bis(vinylenedithio)tetrathiafulvalene (VT), bis(methylvinylenedithio)tetrathiafulvalene (DMVT) or bis(dimethylvinylenedithio)t tetrathiafulvalene (TMVT) with several strong acceptors, such as TCNQ, F 4TCNQ, DDQ, TCNE, Bu 4NBr 3 and I 2, were synthesized by leaving the mixed solution of a donor and an acceptor to stand at ambient temperature. Not only the usual 1:1 (donor:acceptor) complexes but also 2:1, 1:2, 3:1, 3:2 and 5:2 ones were obtained. Unfortunately, a single crystal of good quality was not obtained. The electrical conductivities of the compressed pellet samples were measured by van der Pauw's method. Most of them showed high conductivities of 10 0–10 −1 S cm −1 at room temperature. However, the TCNQ complexes were insulators. The electrical conductivities could be explained on the basis of the i.r. spectra of the complexes and the redox potentials of the donor and acceptor molecules.