Synthesis and structural characterization of a nickel(II) complex with unsymmetrical NNO-donor Schiff base like hydrazone ligand

The nickel(II) complex Ni[C₅H₄N-C(CH ₃)=N-N=C(O)-C₆H₅]₂ (1), containing the potentially tridentate Schiff base like hydrazone ligand (LH) which is the 1:1 condensation product of benzhydrazide and 2-acetylpyridine, was prepared and characterized by IR and UV-Vis spectra, thermal analysis and single crystal X-ray diffraction measurements. Structural investigation shows that the molecule prefers a monoclinic lattice, having space group Cc, a = 10.248(6), b = 19.692(11), c = 12.281(7) Å, β = 91.523(10)°, Z = 4. The central Ni atom is in N₄O₂ coordination sphere developed with the NNO donor sets of the two independently Schiff base like hydrazone ligands with the two Ni-N(pyridine) bonds being significantly longer than the two Ni-N(imino) bonds, 2.096(6), 2.105(6) versus 1.972(6), 2.008(6) Å. The two Ni(II) amide-O bond distances of the chelating ligands are 2.090(6) and 2.092(6) Å respectively.