Abstract.The increasing availability of functionalized BEDT-TTF derivatives in both racemic and enantiopure forms opens up great opportunities for preparing multifunctional materials and chiral conducting systems in the form of crystals, thin films and polymers. Functionalities such as amino and carboxyl will allow attachment to other molecular systems, while intermolecular interactions between substituents, e.g. hydrogen bonding and halegon---halegon interactions, provides additional tools for designing solid state radical cation structures. In this review the syntheses of substituted derivatives of BEDT-TTF and closely related donors are surveyed, along with the structures and properties of the radical cation salts so far prepared, as a stimulus for future application of these versatile and attractive molecules. Particular attention is paid to the preparation of single enantiomers, and to the stereochemical consequences of the synthetic procedures.
IntroductionOrganosulfur donor molecules have been a major focus for research in the preparation of molecular conducting systems, with tetrathiafulvalene 1 and its derivatives playing a leading role initially.1 However, breakthroughs in the last decade for preparing superconducting and hybrid materials have featured bis(ethylenedithio)tetrathiafulvalene 2, also known as BEDT-TTF or ET.2 This molecule shows two reversible oxidations at 0.50 and 0.91 V relative to the Ag/AgCl electrode, ca. 0.15 V more positive than those for TTF, and has been converted into a very large number of radical cation salts. These have been studied by a wide range of techniques stimulated in part by formation of superconducting radical cation salts with anions Cu(NCS) 2