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

Abstract

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, P, a= 7.811(1), b= 10.192(1), c= 13.492(2)Å, α= 97.69(1), β= 90.55(1), γ= 110.88(1)°, Z= 2, R= 0.0405, R′= 0.0454] and [Ru(HL)₂Cl][BF₄]·CH₂Cl₂[monoclinic, P2₁/c, a= 7.576(1), b= 16.072(3), c= 26.083(4)Å, β= 96.02(1)°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)Å. Cyclometallated complexes with ruthenium(II) and rhodium(III) have been prepared and characterised by ¹H NMR spectroscopy.