Hybrid molecular materials based upon organic π-electron donors and inorganic metal complexes.: Conducting salts of bis(ethylenediseleno)tetrathiafulvalene (BEST) with the octahedral anions hexacyanoferrate(III) and nitroprusside

The synthesis, structure and physical characterization of three new radical salts formed by the organic donor bis(ethylenediseleno)tetrathiafulvalene (BEDS-TTF or BEST) and the paramagnetic hexacyanoferrate(ill) anion [Fe(CN)(6)](3-) or the photochromic nitroprusside anion [Fe(CN)(5)NO](2-) are reported: (BEST)(4)[Fe(CN)(6)] (1), (BEST)(3)[Fe(CN)(6)](2) (.) H2O (2) and (BEST)(2)[Fe(CN)(5)NO] (3). Salts 1 and 3 show a layered structure with alternating organic (beta-type packing) and inorganic slabs. Salt 2 shows an original interpenetrated structure probably due to the unprecedented presence of (BEST)(2+) dications. The three salts are semiconductors although salt 1 exhibits a high room temperature conductivity and a semiconducting-semiconducting transition at ca. 150K which has been attributed to a dimerization in the organic sublattice. (C) 2002 Etsevier Science (USA).