Experimental and theoretical spectroscopic study and structural determination of nickel(II) tridentate Schiff base complexes

Some new complexes of [NiL(PR3)] (where L = (E)-1-[(2-amino-5-nitrophenyl)iminio-methyl]naphthal ene-2-olate (L-1), (E)-1-[(2-hydroxiphenyl)iminio-methyl]naphthalene-2-olate (L-2), R = Bu and Ph) containing tridentate ONN and ONO Schiff bases were synthesized and characterized by IR, UV-Vis, H-1-NMR spectroscopy and elemental analysis. The geometry of [NiL1(PBu3)] and [NiL2(PBu3)] complexes were determined by X-ray crystallography. It was indicated that the complexes have a square planar structure and four coordinates in the solid state. Theoretical calculations were also performed to optimize the structures of the ligands and complexes in the gas phase and ethanol solvent, separately to confirm the structures proposed by X-ray crystallography. In addition, UV-Visible and IR spectra of the complexes were calculated and compared with the corresponding experimental spectra to complete the experimental structural identification. (c) 2015 Elsevier B.V. All rights reserved.