Synthesis, characterization and spectroscopic studies of 2,2′-bipyridyl complexes of metal benzenesulfonates

The new transition metal benzenesulfonate (bs) complexes of 2,2'-bipyridyl (bpy) have been synthesized and characterized by elemental analyses, magnetic moments, UV-Vis, IR, thermal analysis techniques. The bs anion does not coordinate to the metal ions and is present as the counter-ion in the Co(II) (2), Ni(II) (3) and CLOD (4) complexes, but coordinates to the Mn(II) ion as a monodentatc ligand. The Mn(II) complex (1) crystallizes in the orthorhombic crystal system with Pbca space group. The complex (1) is the first crystallographically characterized Mn(II) benzenesulfanato complex in which the bs anion is coordinated to metal ion. The manganese centre has a significantly distorted octahedral coordination by two bpy and bs ligands. bs molecules are joined by O7-H7A ... O2 and O7-H7B. O3 hydrogen bonds, forming a centrosymmetnc dimers which are linked by pi-pi interactions. All complexes exhibit similar decomposition characteristics. Magnetic susceptibility measurement shows that complex 2 has orbital interaction.