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Abstract: In the present work, structural studies on (1H-benzimidazol-2-ylmethyl)-N-(4-chloro-phenyl)-amine (L1) and (1H-benzimidazol-2-ylmethyl)-N-(4-iodo-phenyl)-amine (L2) have been done extensively by a variety of physico-chemical techniques. Optimized geometrical structures, harmonic vibrational frequencies, natural bonding orbital (NBO) analysis, and Frontier molecular orbitals (FMO) were obtained by DFT/B3LYP method. TD-DFT calculations help to assign the electronic transitions. The polarizable continuum model (PCM) fails to describe the experimental chemical shift associated with the NH protons as calculated by applying Gauge-invariant atomic orbital (GIAO) method, but a very good correlation between the theoretical and experimental values was achieved by taking into account the specific solute-solvent interactions. DFT calculations showed a good agreement between the theoretical and observed results. These compounds exhibited a high biological activity through the inhibition of the metabolic growth of the investigated bacteria. [Copyright &y& Elsevier]

Abstract: In the present study, structural properties of 2-[(1H-benzimidazol-2-ylmethyl)-amino]-benzoic acid methyl ester have been studied extensively by spectral methods and X-ray crystallography. Quantum mechanical calculations of energies, geometries, vibrational wavenumbers, NMR and electronic transitions were carried out by DFT using B3LYP functional combined with 6-31G(d) basis set. Natural bond orbitals (NBO) analysis and frontier molecular orbitals were performed at the same level of theory. DFT calculations showed good agreement between the theoretical and experimental values of optimized and X-ray structure as well as between the vibrational and NMR spectroscopy. The title compound was screened for its antibacterial activity referring to Tetracycline as standard antibacterial agent. [Copyright &y& Elsevier]

Abstract: (1H-benzimidazol-2-ylmethyl)-(4-nitro-phenyl)-amine (L) and its Pd(II) and Pt(II) complexes have been synthesized as potential anticancer compounds and their structures were elucidated using a variety of physico-chemical techniques. The activation thermodynamic parameters were calculated using non-isothermal methods. Theoretical calculations invoking geometry optimization, charge distribution and molecular orbital description HOMO and LUMO were done using density functional theory. Natural bond orbital analysis (NBO) was performed for the investigation of major stabilizing orbital interactions. The experimental results, and the calculated molecular parameters, bond distances and angles, revealed a square-planar geometry around the metallic center through the pyridine-type nitrogen of the benzimidazole ring (Npy) and secondary amino group (NHsec) and two chlorine atoms. Electrochemical investigation of the complexes showed some irreversible, reversible, and quasi-reversible redox reactions. The synthesized ligand, in comparison to its metal complexes was screened for its antibacterial activity. The cytotoxicity assay of the complexes against three-cell lines breast cancer (MCF7), colon Carcinoma (HCT) and human heptacellular Carcinoma (Hep-G2) was studied. [Copyright &y& Elsevier]

Abstract: (1H-benzimidazol-2-ylmethyl)-(4-methoxyl-phenyl)-amine (L1), (1H-benzimidazol-2-ylmethyl)-(4-methyl-phenyl)-amine (L2) and their Pd(II) and Pt(II) complexes have been synthesized as potential anticancer compounds and their structures were elucidated using a variety of physico-chemical techniques. Theoretical calculations invoking geometry optimization, vibrational assignments, 1H NMR, charge distribution and molecular orbital description HOMO and LUMO were done using density functional theory. Natural bond orbital analysis (NBO) method was performed to provide details about the type of hybridization and the nature of bonding in the studied complexes. Strong coordination bonds (LP(1)N11→σ*(Md (LP(1)N21→σ*(M=Pd or Pt) result from donation of electron density from a lone pair orbital on the nitrogen atoms to the acceptor metal molecular orbitals. The experimental results and the calculated molecular parameters revealed square-planar geometries around the metallic centre through the pyridine-type nitrogen of the benzimidazole ring and secondary amino group and two chlorine atoms. The activation thermodynamic parameters were calculated using non-isothermal methods. The synthesized ligands, in comparison to their metal complexes were screened for their antibacterial activity. In addition, the studied complexes showed activity against three cell lines of different origin, breast cancer (MCF-7), Colon Carcinoma (HCT) and human heptacellular carcinoma (Hep-G2) comparable to cis-platin. [Copyright &y& Elsevier]

Abstract: [NiL1,2Cl2(OH2)3]·zH2O and [ZnL1,2(CH3CO2)2] (L1 =(1H-benzimidazol-2-ylmethyl)-N-phenyl amine, z =0 and L 2 =2-[(1H-Benzimidazol-2-ylmethyl)-amino]-benzoic acid methyl ester, z =1) complexes have been synthesized and characterized by a variety of physico-chemical techniques. The central Ni(II) ion is coordinated by only the pyridine-type nitrogen (Npy) of benzimidazole ring, three water molecules and two chlorido ligands forming a distorted octahedral geometry. Five coordinated zinc complexes were obtained, where the coordination sphere of zinc ion is made up of secondary amino group (NHsec), Npy and two acetate groups, one acts as a unidentate and the other as a bidentate. A theoretical DFT/UB3LYP method combined with LANL2DZ basis set shows that all the metal–ligand bonds are of the L→M type. Electronic structures have been calculated using TD-DFT method. The antibacterial activity of NiL2 complexes decreases by the introduction of COOCH3 group in the ortho-position of the aniline moiety. [Copyright &y& Elsevier]