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Mono‐ and binuclear benzimidazole based half‐sandwich organoruthenium(II) compounds; [Run(triazolateCOOCH3,COOCH3)n(η6‐p‐Cym)nL]0/+/2+ (n = 1, L = LCH2CH3 (7) and HLSO3H (8); n = 2, L = LDTP (9)) were synthesized by [3+2] free catalyzed cycloaddition reaction of azide complexes 4–6 with electron‐poor alkyne dimethyl acetylene dicarboxylate. In comparison with the parent [RunCln(η6‐p‐Cym)nL]0/+/2 complexes (1–3), the lysozyme binding affinity of the corresponding triazolate compounds 7–9 was investigated by electrospray ionization mass spectrometry. Complexes bearing benzimidazole ligand with an alkylated sulfonate side chain (2 and 8) are able to bind lysozyme noncovalently, which have not been clearly seen by other investigated Ru(II) complexes. The complexes were assessed for their potential antimicrobial activity against some representative microbes. Complex 9 exhibits antifungal activity against C. albicans (MIC = 24 nm) and C. neoformans (MIC = 12 nm), perfect blood compatibility as well as no toxicity to non‐malignant cell line (human embryonic kidney cells (HEK293). [ABSTRACT FROM AUTHOR]

A series of photoactivatable CO‐releasing molecules (PhotoCORMs) was prepared from manganese pentacarbonyl bromide and 1H‐benzimidazol‐2‐ylmethyl‐(N‐phenyl)amine ligands (L) bearing different electron‐donating and electron‐withdrawing groups R = H, 4‐CH3, 4‐OCH3, 4‐Cl, 4‐NO2, 2‐, 3‐, and 4‐COOCH3 on the phenyl substituent to give octahedral manganese(I) complexes of the general formula [MnBr(CO)3(L)]. Aerated DMSO solutions of the compounds are stable in the dark for 16 h with no CO release. However, the compounds rapidly release CO upon illumination at 412–525 nm, depending on the substitution pattern. Its influence on the photophysical and photochemical properties was systematically explored using UV/Vis spectroscopy and CO release measurements with a commercial gas sensor system. In the nitro‐substituted compound, the electronically excited state switched from benzimidazole‐ to phenyl‐centered, leading to a markedly different photochemical behavior of this visible‐light activated PhotoCORM. [ABSTRACT FROM AUTHOR]

The lysozyme binding affinity of new Au(III) complexes, bearing pyridylbenzimidazole ligands, was investigated by ESI‐MS and UV/Vis. Metalation of lysozyme happened mainly by {Au}n+, {AuCl}0/n+ and {AuCl2}n+/–. The appendage sulfonate group of pyridylbenzimidazole ligand system played a role in determining the products of interaction of HEWL with Au(III) complexes. The hydrophilic sulfonate group inhibited the ligand cleavage via the participation in several coulombic and H‐bond interactions giving several AuLn+ containing adduct peaks (L = 1‐[(pyridin‐2‐yl) benzimidazole]‐propyl‐sulfonic acid). The stability of the complexes in presence of ascorbic acid was examined by UV/Vis and 13C NMR. To recognize if His15 side‐chain is the metalation site of HEWL, the interactions between the complexes and imidazole, as a simple model of histidine, were investigated by 1H and 13C NMR. The DNA binding studies of the complexes were reported. For this class of Au(III) complexes, it is preferred to decorate the pyridylbenzimidazole system with ethyl group rather than sulfonate and phthalimido group to have a complex with interesting antifungal activity against Candida albicans and Cryptococcus neoformans var. grubii. Au(III) complex, having sulfonate group, is noncytotoxic to non‐malignant cells (human embryonic kidney cells (HEK293)), shows negligible hemoglobin release and is safe to the normal cells if applicable. [ABSTRACT FROM AUTHOR]

Introduction of tetrazolate moiety in the coordination sphere of Pd(II) complex, functionalized with tridentate benzimidazole ligand, via the catalyst [3+2] cycloaddition reaction, gave rise to potential antibacterial properties. [Display omitted] Two [PdN 3 L]PF 6 complexes (L = 2,6-bis(1-ethyl-benzimidazol-2́-yl)pyridine (LBZ) and 4-(2-pyridyl)-2,2′:6′,2′'-terpyridine (LPY)) underwent catalyst-free 1,3-dipolar cycloaddition coupling with phenyl isothiocyanate at the room temperature giving the corresponding tetrazole–thiolato complexes. 1H NMR studies showed that the N1-isomer appeared first in the catalyst-free coupling, then gradually isomerized to the more stable tetrazole–thiolato isomer. The interconversion of N1-isomer into the S-isomer is accompanied by a decrease of the greater steric demand of the 5-membered ring. Tetrazolate complex of LBZ displayed higher antifungal activity (MIC ≤ 0.25 μg/mL) than the chloride analogue (MIC = 0.5–1.0 μg/mL) and the reference drug, Fluconazole (MIC = 0.125–8.0 μg/mL) against Candida albicans and Cryptococcus neoformans. The treated non-cancerous human embryonic kidney cells (HEK293) showed no cytotoxicity and no haemolysis release at the measured concentrations of the chloride complex of LBZ and tetrazolate complex of LPY. [ABSTRACT FROM AUTHOR]

New cis-platin analogs Pd II and Pt II complexes of (1H-benzimidazol-2-ylmethyl)-N-(4-chloro-phenyl)-amine (L Cl ) and (1H-benzimidazol-2-ylmethyl)-N-(4-iodo-phenyl)-amine (L I ) were prepared as potential antitumor compounds, characterized (elemental analysis, TG/DTA, FT IR, 1 H NMR, MS, UV–Vis. and conductance measurements) and tested for their cytotoxic activities against MCF7, HCT and HEPG2. The antibacterial activity was tested on against Staphylococcus aureus , Bacillus subtilis , Streptococcus faecalis , Escherichia coli , Pseudomonas aeruginosa and Neisseria gonorrhea . The effect of the aniline substituent on the toxicity was discussed. The experimental studies were complemented by quantum chemical calculations. TD-DFT calculations were carried out to understand the electronic structure and to explain the related experimental findings. Natural bond orbital analysis was performed to provide details about the electronic arrangement, type of hybridization and the nature of bonding. [ABSTRACT FROM AUTHOR]

Highlights: [•] Binuclear and polynuclear CuII acetate complexes were prepared. [•] Strong anti-ferromagnetic behavior was observed. [•] Presence of another bridging ligand altered the magnetic behavior. [•] Anionic effect was established by comparison with the chloro complex. [•] Correlation between experimental and theoretical data was performed. [Copyright &y& Elsevier]

Abstract: Two new charge transfer complexes (L1,2 →DDQ; L1 =(1H-benzimidazol-2-ylmethyl)-N-phenyl amine, L2 =(1H-benzimidazol-2-ylmethyl)-(4-nitro-phenyl)-amine, and DDQ=2,3-dichloro-5,6-dicyano-1,4-benzoquinone) have been synthesized and characterized by a variety of physico-chemical techniques. The experimental studies were complemented by quantum chemical calculations at DFT/B3LYP level of theory. Electronic structures were investigated by TD-DFT method and the descriptions of frontier molecular orbitals and the relocation of the electron density were determined. Stability of the molecule arises from hyperconjugative interactions, charge delocalization and hydrogen bonding has been analyzed using natural bond orbital (NBO) analysis. 1H NMR chemical shifts were computed at B3LYP/6-311+G(2d,p) level of theory by Gauge-invariant atomic orbital (GIAO) in DMSO as a solvent using the polarizable continuum model (PCM). Photometric titration was carried out to shed more light about the stoichiometry of the formed complexes in the solution. Spectral data were analyzed in terms of formation constant, molar extinction coefficient, oscillator strength, dipole moment, standard free energy, and ionization potential. [Copyright &y& Elsevier]

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 work, structural studies on 2-chloromethyl-1H-benzimidazole hydrochloride have been performed extensively by X-ray crystallography, 1H NMR, FT-IR, UV/vis, and elemental analysis. The title compound crystallizes in a monoclinic space group P2 1 /c with a =7.1982 (3)Å, b =9.4513 (5)Å, c =14.0485 (7)Å and β =102.440 (3)° forming an infinite chain structure parallel to “b” axis through the intermolecular hydrogen bond. Optimized geometrical structure, harmonic vibrational frequencies, natural bonding orbital (NBO) and frontier molecular orbitals (FMO) were obtained by DFT/B3LYP method combined with 6-31G(d) basis set. TD-DFT calculations help to assign the electronic transitions. The 1H NMR chemical shifts were computed at the B3LYP/6-311+G(2d,p) level of theory in different solvents by applying GIAO method using the polarizable continuum model (PCM). The title compound was screened for its antibacterial activity referring to Tetracycline as a standard antibacterial agent. [Copyright &y& Elsevier]

Abstract: [MLCl2] (L = (1H-benzimidazol-2-ylmethyl)-N-(4-bromo-phenyl)-amine; M = Pd & Pt) and [PdL(OH2)2]∙2X∙zH2O (X = Br, I, z = 2; X = SCN, z = 1; X = NO3, z = 0) complexes have been synthesized as potential anticancer compounds and their structures were elucidated using elemental analysis, spectral, thermal analysis and X-ray powder diffraction. The benzimidazole (L) crystallizes in the space group P21/c with a = 8.6660(3) Å, b = 16.6739(7) Å, c = 9.8611(4) Å and β = 113.505(3) ° and forms an infinite chain structure with a trans-zigzag type along the crystallographic axis "a", through the intermolecular H–bond. FT-IR and 1H NMR studies revealed that the ligand L is coordinated to the metal ion via the pyridine-type nitrogen (Npy) of the benzimidazole ring and secondary amino group (NHsec). Quantum mechanical calculations of energies, geometries, vibrational wavenumbers, and 1H NMR of the benzimidazole L and its complexes were carried out by DFT/B3LYP method combined with 6–31G(d) and LANL2DZ basis sets. Natural bond orbital (NBO) analysis and frontier molecular orbitals (FMO) were performed at B3LYP/LANL2DZ level of theory. The benzimidazole L, in comparison to its metal complexes was screened for its antibacterial activity. The complexes showed cyctotoxic effects against human breast cancer (MCF7), hepatocarcinoma (HepG2) and colon carcinoma cells (HCT). The platinum complex (6) exhibited a moderate antitumor activity against MCF7 with IC50 = 10.2 μM comparing to that reported for cis-platin 9.91 μM. [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: [MLCl2]·zH2O (L=(1H-benzimidazol-2-ylmethyl)-N-phenyl amine; M=Pd, z =0; M=Pt, z =1) and [PdL(OH2)2]·2X·zH2O (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 1H NMR studies revealed that the benzimidazole L is coordinated to the metal ions via the pyridine-type nitrogen (Npy) of the benzimidazole ring and secondary amino group (NHsec). Quantum mechanical calculations of energies, geometries, vibrational wavenumbers, and 1H 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=58μg/mL) than the standard tetracycline (MIC=82μg/mL). The complexes showed cytotoxicity against breast cancer, Colon Carcinoma, and human heptacellular Carcinoma cells. The platinum complex (6) displays cytotoxicity (IC50 =12.4μM) against breast cancer compared with that reported for cis-platin 9.91μM. [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]