CURRENT TRENDS IN TETRATHIAFULVALENE CHEMISTRY - TOWARDS INCREASED DIMENSIONALITY

Some of the current directions in research on conducting and superconducting charge-transfer salts based upon tetrathiafulvalene (TTF) pi-electron donor molecules are reviewed. Particular emphasis is placed upon new donor molecules, which have been studied with the aim of increasing the dimensionality in the solid state, thereby gaining control over the intermolecular architecture and long-range electron delocalization. Important structural features of the pi-donor in this respect are: close intermolecular sulfur-sulfur contacts, attachment of hydrogen-bonding substituents, and extended rr-conjugation. The electronic and structural properties of selected TTF derivatives and their salts are discussed. Synthetic schemes are also presented.