Structural and in vitro cytotoxicity studies on 1H-benzimidazol-2-ylmethyl-N-phenyl amine and its Pd(II) and Pt(II) complexes

[MLCL2]center dot zH(2)O (L=(1H-benzimidazol-2-ylmethyl)-N-phenyl amine; M = Pd, z= 0; M = Pt. z= 1) and PdL(OH2)(2)]center dot 2X center dot zH(2)O (X = Br, I, NO3, z = 0; X =SCN, z = 1) complexes were synthesized as potential anticancer compounds and characterized by elemental analysis, spectral and thermal methods. FT-IR and H NMR studies revealed that the benzimidazole L is coordinated to the metal ions via the pyridine-type nitrogen (N-py) of the benzimidazole ring and secondary amino group (NHsec). Quantum mechanical calculations of energies, geometries, vibrational wavenumbers, and H-1 NMR of the benzimidazole L and its complexes were carried out by density functional theory using B3LYP functional combined with 6-31G(d) and LANL2DZ basis sets. Natural bond orbitals (NBOs) and frontier molecular orbitals were performed at B3LYP/LANL2DZ level of theory. The synthesized ligand, in comparison to its metal complexes was screened for its antibacterial activity. The benzimidazole L is more toxic against the bacterium Staphylococcus aureus (MIC= 58 mu g/mL) than the standard tetracycline (MIC= 82 mu g/mL). The complexes showed cytotoxicity against breast cancer, Colon Carcinoma, and human heptacellular Carcinoma cells. The platinum complex (6) displays cytotoxicity (IC50=12.4 mu M) against breast cancer compared with that reported for cis-platin 9.91 mu M. (C) 2011 Elsevier B.V. All rights reserved.