New complexes of Mn(II), Co(II), Ni(II) AND Cu(II) with 2,2’- OR 2,4’-bipyridine and formates (Synthesis, thermal and other properties)

Abstract

New mixed-ligand complexes with empirical formulae: Mn(2-bpy)1.5L2·2H2O, M(2-bpy)2L2·3H2O (M(II)=Co, Cu), Ni(2-bpy)3L2·4H2O and M(2,4’-bpy)2L2·2H2O (where 2-bpy=2,2’-bipyridine, 2,4’-bpy=2,4’-bipyridine; L=HCOO– ) have been obtained in pure solid-state. The complexes were characterized by chemical and elemental analysis, IR and VIS spectroscopy, conductivity (in methanol and dimethylsulfoxide). The way of metal-ligand coordination discussed. The formate and 2,4’-bpy act as monodentate ligands and 2-bpy as chelate ligand. The new complexes with ligand isomerism were identified. During heating the complexes lose water molecules in one or two steps. Thermal decomposition after dehydration is multistage and yields corresponding metal oxides as final products. A coupled TG-MS system was used to analysis principal volatile thermal decomposition (or fragmentation) products of Ni(2,4’-bpy)2(HCOO)2·2H2O under dynamic air or argon atmosphere.