Polymeric and mixed ligand complex of cobalt(II) and 4-hydroxybenzhydrazide: Crystal structure and vibrational spectroscopy

Reaction of CoSO4 and 4-hydroxybenzhydrazide in water/methanol solution resulted in polymeric complex with C=O and NH2 groups of organic ligand, two water molecules and two oxygen atoms of two sulfate anions in metal coordination sphere. The X-ray analysis revealed that the complex is in the form of polymer chain of the helical structure formed due to sulfate bridge geometry and intra-chain hydrogen bonds. The variety of coordinated ligands is reflected in the vibrational spectra where six different metal-ligand modes were found. The bands related to stretching and bending vibrations of NH2, NH, OH groups as well as water molecules were located with help of hydrogen-deuterium substitution. For proposed band assignment the animation of DFT calculated normal modes was employed. (C) 2010 Elsevier B.V. All rights reserved.