SYNTHESIS AND MOLECULAR-STRUCTURE OF NEW FAMILIES OF IRIDIUM(III)-CP-ASTERISK AND RHODIUM(III)-CP-ASTERISK COMPLEXES DERIVED FROM 1,2-DICYANOETHENE-1,2-DITHIOLATE, 2,2'-BIIMIDAZOLE OR 2,2'-BITHIAZOLE - SINGLE-CRYSTAL STRUCTURES OF [(ETA-5-ME5C5)IR(BIIMH2)CL]CL AND [(ETA-5-ME5C5)RH(DCDT)]

Reaction of [(eta5-Me5C5)MCl2]2 (M = Ir or Rh) with 1,2-dicyanoethene-1,2-dithiolate (dcdt2-), 2,2'-biimidazole (biimH-2), or 2,2'-bithiazole (bith) affords various d6 complexes in high yield. Pentaco-ordinate compounds such as [(eta5-Me5C5)M(dcdt)] (M = Ir or Rh) and hexacoordinate complexes of the type [(eta5-Me5C5)M(biimH-2)Cl]Cl, (M = Ir or Rh) or [(eta5-Me5C5)Ir(bith)Cl]Cl have been synthesized and characterized. [(eta5-Me5C5)Rh(dcdt)] crystallizes in the orthorhombic space group C222(1) with unit cell parameters a = 11.972 (3), b = 15.072 (4), c = 16.456 (5) angstrom. Refinement of 859 observed reflections led to the final values of R = 2.31 and R(w) = 3.46%. [(eta5-Me5C5)Ir(biimH-2)Cl]Cl crystallizes in the orthorhombic space group P2(1)2(1)2(1) with unit cell parameters a = 14.610 (4), b = 14.556 (6), c = 8.654 (3) angstrom. Refinement of 1630 observed reflections led to a value of R = 1.86 and R(w) = 2.65%. The biimH-2-iridium complex exhibits a characteristic three-legged "piano-stool" arrangement and the dcdt-rhodium complex a flattened basket shaped arrangement.