HYDRAZINIUM CATION AS A LIGAND - PREPARATION AND SPECTRAL, THERMAL AND XRD STUDIES ON HYDRAZINIUM METAL PHTHALATES

Octahedral bis-hydrazinium metal phthalates, (N2H5)(2)M[C6H4(COO)(2)](2), where M=Ni(II) for phthalate and M=Co(II), Ni(II) and Zn(II) for isophthalate or terephthalate and tetrahedral hydrazinium zinc isophthalate and terephthalate, N2H5Zn[C6H4(COO)(2)](1.5), have been prepared and characterised by physicochemical techniques, The three isomeric dihydrazinium salts of phthalic, isophthalic and terephthalic acids have been exploited in the preparation of the complexes with metal nitrate hydrates in aqueous medium. Infrared absorption bands in the region 990-1015 cm(-1), due to V-N-N confirm the coordination of N2H5+ to the metal. IR data also confirm the unidentate nature of carboxylate groups, Simultaneous TG-DTA of the complexes have been studied in air and they show that both isophthalate and terephthalate complexes decompose via metal isophthalate/terephthalate hydrazinate intermediates, whereas phthalate complex decomposes via metal phthalate intermediate to give metal oxide as the final product. The X-ray powder diffraction patterns show isomorphism not only among the isophthalate complexes and terephthalate complexes but also between the two series.