STRUCTURAL AND ELECTRONIC STUDY OF DONORS COMPOSED OF 2 TTF MOIETIES LINKED BY TELLURIUM BRIDGES

The details of the crystal and electronic structure of two compounds composed of two TTF (tetrathiafulvalene) moieties linked by one and two tellurium atoms have been studied. In each case the two TTF units in a given molecule differ: in one the difference is manifested in the intramolecular bond lengths, while in the second case there is a difference in the degree of molecular planarity. Because of the difference in conformational degrees of freedom, the mutual disposition of the TTF units also differs in the two structures, as do the type and number of the intermolecular interactions. It is suggested that the inequivalence between the two chemically identical TTF units in donors of this type, can lead to a quite large localization of the HOMO in one of the two TTF moieties. The implications of such a localization for the transport properties of this type of donors are discussed.