BENZOATE COMPLEXES OF DIPOSITIVE FIRST ROW TRANSITION-METAL IONS WITHHYDRAZINE

Hydrazine metal benzoate complexes of the formula M(C6H5COO)(2)N2H4, w here M = Mn and Zn and bis(hydrazine) metal benzoate complexes of the formula M(C6H5COO)(2)(N2H4)(2), where M = Fe, Co, Ni, Zn and Mg, and b is(hydrazinium) nickel benzoate complex have been prepared in aqueous solution by the reaction of hydrazinium benzoate and the corresponding metal nitrate hydrates. The complexes were characterised by chemical analyses, magnetic, spectral, thermal and XRD studies, The magnetic mo ments and electronic spectra reveal that M(C6H5COO)(2)N2H4 is tetrahed ral and the other complexes are octahedral. Infrared spectra show that hydrazine is bidentate bridging, while N2H5+ and carboxylate ions are unidentate. Simultaneous TG-DTA shows that the complexes undergo both exothermic and endothermic decomposition via metal benzoate or oxalat e intermediates to form the metal oxide. The benzoate intermediates fo r the Mn, Co and Mg complexes melt before decomposition, whereas the ( N2H5)(2)Ni(C6H5COO)(4) complex itself melts before decomposition. X-ra y powder pattern reveals that tetrahedral complexes are isomorphous an d except (N2H5)(2)Ni(C6H5COO)(4), the other octahedral complexed are i somorphous.