Abstract
[M(NTZ)Cl-2] (M = Pd(II) (1), Pt(II) (2) and NTZ = Nitazoxanide) and [Ru(NTZ)Cl-3(OH2)] (3) complexes have been synthesized and characterized by elemental analysis, thermogravimetric analysis, IR, 1H NMR, conductance and magnetic measurements. NTZ is coordinated to the metal ions as a bidentate ligand via the N-atom of the thiazole ring and amide C=O. The susceptibility of Staphylococcus aureus and Escherichia coli towards NTZ and its complexes has been evaluated. The calculated electronic structures and the related electronic transitions have been obtained at TD-DFT/B3LYP/LANL2DZ level of theory. Upon the chelation, the value of the natural charge of Ru(III) ion (+0.182e) was found to be lower than those of Pd(II) and Pt(II) ions (similar to+0.398e) in their complexes, which reflects the higher complexation ability of NTZ towards the high oxidation state and low-d-orbital population metal ion. Complex 3 is existing in a low-spin octahedral arrangement. The DC magnetic measurements in terms of Weiss constant revealed the presence of the intermolecular interactions among the spin carriers. The low stability of 1-3 in DMSO and the rate of the releasing of NTZ was the factor which reproduces the order of the toxicity (NTZ > 2 > 3 > 1) against the tested microbes. (C) 2016 Elsevier B.V. All rights reserved.