DIFFERENT BONDING MODES IN OCTAHEDRAL COMPLEXES OF 6-(2-THIENYL)-2,2'-BIPYRIDINE (HL) WITH TRANSITION-METAL IONS - CRYSTAL-STRUCTURES OF (RU(HL)(PY)CL3) (PY = PYRIDINE) AND (RU(HL)2CL)(BF4).CH2CL2

The ligand 6-(2-thienyl)-2,2'-bipyridine (HL) has been shown to adopt terdentate N2S, bidentate N2 or terdentate cyclometallated N2C bonding modes in ruthenium and rhodium complexes. The crystal and molecular structures of the complexes mer-[Ru(HL)(py)Cl3] (py = pyridine) [triclinic, P1BAR, a = 7.811(1), b = 10.192(1), c = 13.492(2) angstrom, alpha = 97.69(1), beta = 90.55(1), gamma = 110.88(1)-degrees, Z = 2, R = 0.0405, R' = 0.0454] and [Ru(HL)2Cl][BF4].CH2Cl2 [monoclinic, P2(1)/c, a = 7.576(1), b = 16.072(3), c = 26.083(4) angstrom, beta = 96.02(1)-degrees Z = 4, R = 0.0504, R' = 0.0585] are reported. The former complex contains a bidentate N2-bonded HL ligand and a meridional arrangement of the chlorine atoms, whilst the latter contains two independent HL ligands, one of which is a bidentate N2-donor, and the other a terdentate N2S-donor, with Ru-S 2.380(2) angstrom. Cyclometallated complexes with ruthenium(II) and rhodium(III) have been prepared and characterised by H-1 NMR spectroscopy.