HALOGENATED TETRATHIAFULVALENES (TTFS) - PREPARATION, X-RAY STRUCTUREAND CYCLIC VOLTAMMETRY OF TETRACHLORO-2,3-DICHLORO-6,7-DIMETHYL-TTF AND TETRACHLORO-2,3-DIIODO-6,7-DIMETHYL-TTF

Lithiation of tetrathiafulvalene (TTF) with butyllithium in tetrahydro furan (THF) followed by quenching with hexachloroethane (HCE), 1,2-dib romotetrachloroethane (BCE) or 1,2-dibromotetrafluoroethane (BFE) affo rds improved yields of both tetrabromo-TTF (Br4TTF) and tetrachloro-TT F (Cl4TTF), compared to earlier reports. By a similar procedure, 2,3-d imethyl-TTF (2,3-Me(2)TTF) undergoes lithiation followed by chlorinati on with HCE, bromination with BCE or BFE and iodination with perfluoro hexyl iodide (PFHI), affording 2,3-dichloro-6,7-dimethyl-TTF (Cl(2)Me( 2)TTF), 2,3-dibromo-6,7-dimethyl-TTF (Br(2)Me(2)TTF) and 2,3-diiodo-6, 7-dimethyl-TTF (I(2)Me(2)TTF), respectively. The single-crystal struct ures of Cl4TTF, Cl(2)Me(2)TTF and I(2)Me(2)TTF have been determined. H alogen substitution on the TTF skeleton leads to a variety of packing features in the crystal structures of the resulting compounds.