Synthesis, spectroscopic and X-ray characterization of a copper(II) complex with the Schiff base derived from pyridoxal and aminoguanidine: NMR spectral studies of the ligand

A copper(II) complex with the pyridoxal-aminoguanidine (PL-AG) Schiff base adduct, as an organic compound of the very potent biological activity and promising pharmacological importance in the treatment of diabetic complications, has been prepared and characterized. The X-ray structural analysis of the [CuCl2(PL-AG)] complex showed that it has a distorted pseudo-square-pyramidal (4 + 1) structure with the tridentate ONN Schiff base in the equatorial plane, with the Cu–O(1), Cu–N(1) and Cu–N(3) bond lengths of 1.917(2) Å, 1.930(2) Å and 1.984(2) Å, respectively. The bond length of the equatorial Cu–Cl(1) is 2.279(1) Å, while that of the apical Cu–Cl(2) is 2.792(1) Å. Pyridoxal fragment is coordinated in its zwitterionic form. In addition to the X-ray structural analysis, the complex was characterized by IR spectrometric, conductometric and magnetic techniques, and the ligand itself by IR, 1H and 13C NMR spectra.