Synthesis, Spectral, Thermal and X-ray Powder Diffraction Studies on Hydrazine Bridged Metal and Mixed Metal Para Nitrobenzoate Complexes

Abstract

Bis-hydrazine metal(II) p-nitrobenzoates, [M(p-NO₂C₆H₄COO)₂(N₂H₄)₂], where  M= Co, Ni, Zn or Cd have been prepared by mixing an aqueous solution of respective metal nitrate hydrate with an aqueous solution containing a mixture of p-nitro benzoic acid and hydrazine hydrate in appropriate ratio. These complexes have been characterised by analytical, spectral, thermal and X-ray powder diffraction studies. The IR spectra of these complexes indicate the bridging bidentate nature of hydrazine moieties and monodentate nature of carboxylate ions. On thermal degradation these complexes except zinc complex undergo one step decomposition to yield respective metal oxide as the final product. However, the zinc complex undergoes dehydrazination in the first step followed by ligand pyrolysis to give ZnO as the final residue. X-ray powder diffraction pattern indicates the isomorphism among the complexes.

The mixed metal complexes, [M_1/3Co_2/3(p-NO₂C₆H₄COO)₂(N₂H₄)₂]  have also been prepared using aqueous solution containing a mixture of metal nitrate hydrates and cobalt nitrate hexahydrate in 1:2 ratio instead of metal nitrate hydrate. These complexes on thermal degradation yield respective metal cobaltites with high degree of purity as the final product. The formations of these cobaltites were confirmed by chemical analysis, IR spectra and X-ray powder diffraction studies.