Nickel(II) and copper(II) complexes with Schiff base ligand 2,6-diacetylpyridine bis(carbohydrazone): Synthesis and IR, mass, 1H NMR, electronic and EPR spectral studies

Nickel(II) and copper(II) complexes with general formula [M(H3DAPC)X] and [M(H2DAPC)H2O], where M = Ni(II) and Cu(II), X = NO3−, Cl− and CH3COO−, and DAPC = 2,6-diacetylpyridine-bis(carbohydrazone), have been synthesized and structurally characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements and spectral techniques like IR, UV and EPR. The nickel(II) and copper(II) complexes are octahedral and tetragonal coordination geometries, respectively. The EPR spectra of copper complexes in powdered form show a broad signal with g values in order g|| > g⊥ > 2.0023. The value of covalency factor β and orbital reduction factor k accounts for the covalent nature of the complexes.