Synthesis and physicochemical studies of carboxylic acid hydrazide complexes of some nickel(II) β-diketonates

Abstract

Twelve carboxylic acid hydrazide complexes of nickel(II) β-diketonates were synthesised and characterised by metal analysis, magnetic moment susceptibility, molar conductivity, solid reflectance electronic and infrared spectra measurements. The acid-hydrazide ligands were compared with their corresponding complexes. The infrared spectra bands of the complexes indicated that the oxygen atom of nickel(II) β- diketonates and the amino nitrogen were coordinated to the metal ion. The solid reflectance electronic spectral measurements displayed the three allowed transitions expected of an octahedral nickel(II) compound which are the 3A2g → 3T2g ; 3A2g → 3T1g (F) and 3A2g → 3T1g (P) while some showed spin-forbidden transitions. The room temperature magnetic moments obtained ranged between 1.75-4.32 B.M corroborating the electronic spectral measurements for the compounds. The molar conductivity measurements in nitromethane found in the range 1.80-7.01 ohm-1cm2mol-1 showed that they are non-electrolytes which are lower than reported value of 60-118 ohm-1cm2mol-1 for a 1:1 electrolyte. +9owever, the high values observed for this complexes might be suggestive of antiferromagnetism operating through a Ni-Ni bond in a dimeric structure, such that each Ni atom had a moment of 2.35 B.M