89505-04-4

A new nickel(II) complex, [NiL2]Cl2 (L = N,N-bis(benzimidazol-2-yl-methyl)amine), was synthesized and its crystal structure was determined. According to X-ray crystallographic studies, each nickel(II) ion was six-coordinated with six nitrogen atoms of two L ligands. The complex crystallizes in triclinic system, space group P1?, a = 9.764(3) ?, b = 11.032(3) ?, c = 16.402(5) ?, α = 80.529(6)°, β = 79.180(7)°, γ = 74.232(6)°, and Z = 2. The title complex forms two-dimensional hydrogen bond network structures between the chlorine atoms and the nitrogens of L. The IR and UV spectroscopy were measured. The absorption bands of d-d electron transition are assigned, the values of Dq and B were calculated according to the electronic spectrum of the complex.

The preparation and characterisation of 1(CH3CO2)2> (1), (9), 1Cl3> (10), 2Cl3> (2), and 12(μ-O)2>2 (3) are reported where L1 and L2 are bis(benzimidazol-2-ylmethyl)amine and bis(benzimidazol-2-ylmethyl)methylamine.The molecular structures of (1), (2), and (3) were determined by X-ray diffraction.Complex (1) exists as a discrete, neutral, mononuclear species in the solid state.The manganese(II) ion is five-coordinate with the tridentate ligand bound in a meridional manner.Both acetates are monodentate with Mn-O distances of 2.076(5) and 2.158(5) Angstroem.Complex (9) contains a 10+ core, formally 4MnII:2MnIII.Complex (2) is neutral, mononuclear, distorted octahedral.The ligand co-ordinates in a similar manner to that seen in (1) and the chlorides occupy the three remaining meridional sites, with Fe-Cl(equatorial) 2.318(5) Angstroem and Fe-Cl(axial) 2.322(5) and 2.433(5) Angstroem.The Moessbauer spectrum of (10) at room temperature comprises a quadrupole doublet: δ= 0.40(1), ΔEQ= 0.33(2) mm s-1.Complex (3) is a dinuclear iron(III) species containing the triply bridged 2+ core.The Fe...Fe distance is 3.075(5) Angstroem and the Fe-O(oxo)-Fe angle is 117.0(6) deg.The high-spin iron(III) centres are antiferromagnetically coupled with J= -116 cm-1.The Moessbauer spectra of (3) at room temperature and 70 K consist of doublets with δ= 0.44(1), ΔEQ= 1.37(2), and δ= 0.55(1), ΔEQ= 1.30(2) mm s-1 respectively.

The corrosion inhibition of N,N′-bis(benzimidazole-2-yl-methyl)amine (L1) and N, N′-bis(benzimidazole-2-yl-methyl)hydroxyethylamine (L2) was analyzed by electrochemical and theoretical methods. The data show that ligands form an adsorption layer over an iron surface, obeying the Langmuir isotherm of -32.96 kJ mol-1); the value are higher than -20 kJ mol-1 but less than -40 kJ mol-1, belonging to a conversion stage of physical adsorption to chemical adsorption or a comprehensive adsorption. This is consistent with fractal dimension of the electrode surface, estimated by an impedance depression angle of a semicircle that the surface is homogeneously covered by the formation of an inhibitor film. Furthermore, the electronic parameters of the ligands were analyzed by DFT, showing that L1 and L2 possesses corrosion inhibition properties that give up its p orbital electron density through its HOMO orbital to the metal LUMO to form an adsorption layer, and this has been proved theoretically by the interaction of ligands with Fe30. In addition, we have collected corrosion inhibition data for around 70 organic compounds reported in the literature, and the inhibition data plotted against different inhibitors, showing that amine ligands are good corrosion inhibitors.

Recent advances in dinuclear copper complexes as mimics of the catalytic centers of tyrosinase and catechol oxidase allowed the reproduction of the structural and mechanistic aspects of the enzymes. However, a challenging objective is the development of chiral complexes for bioinspired enantioselective oxidation reactions. Here, we report the synthesis and characterization of a dinuclear copper(II) complex with a new chiral diamino-m-xylenetetra(benzimidazole) ligand (L55Bu4), which has chiral centers at the four 2-methylbutyl substituents of the benzimidazole rings. The spectral characteristics, ligand binding properties, and reactivity of [CuII2L55Bu4]4+ in the catalytic oxidations of several biogenic catechols (L-/D-dopa, L-/D-DopaOMe, and L-/D-norepinephrine) and thioanisole are reported. The best discriminating properties are displayed towards the DopaOMe derivatives, for which the oxidation rate of the L enantiomer is approximately one order of magnitude larger than that of the opposite D isomer. A dinuclear copper(II) complex derived from a chiral hexadentate nitrogen ligand is reported as a new catalyst for asymmetric oxidations. For biogenic catechols as model substrates, the best enantioselectivity is obtained in the oxidation of the methyl esters of L-/D-Dopa, for which 70%ee is obtained in favor of the L enantiomer.

Herein, a novel non-symmetric tripodal receptor has been synthesized and reported as a fluorescent chemosensor for fluoride ions with a remarkable red shift of 100 nm. The receptor was designed with benzimidazole and amide -NH functionalities to achieve fluorescence signals during anion sensing; the recognition behaviour of the probe towards fluoride ions was investigated using emission spectroscopy based on a ratiometric change with the limit of detection as low as 0.875 ppb as well as a visual change in colour from violet to cyan under UV light. 1H NMR studies confirmed the initial formation of the-NH?F- hydrogen bond and the subsequent deprotonation of benzimidazole and amide upon the addition of fluoride ions. In addition, an INHIBIT-type logic gate at the molecular level could be fabricated using the reversibility and the reusability of the probe towards the F- and H+ ions. Moreover, visual detection of fluoride ions in the solid state was feasible as the receptor-coated TLC plates and paper strips detected the former under UV light. In the protonated form, the asymmetric unit encompasses two molecules of the non-symmetrical receptor that bind two molecules of sulfate anions, and the benzimidazole -NHs have been found to be potent hydrogen bond donors.

A new unsymmetric tripodal ligand bis(2-benzimidazolylmethyl)(2-pyridylmethyl)amine (L) bearing two kinds of chromophores benzimidazole and pyridine has been synthesized, and two series of lanthanide(in) complexes [LnL(NO3)3]-C2H5OH (Ln = La, Sm, Eu, Gd, Tb or Tm) and [LnLCl3(H2O)]-C2H5OH (Ln = La, Sm, Eu, Tb or Ho) have been characterized by elemental analyses, FAB mass spectra, 'H NMR, conductivity measurements, and IR spectra. The crystal and molecular structures of the three complexes [SmL(NO3)3]-C2HjOH 1, [GdL(NO3)3]-C2H5OH 2, and [SmLCl^HjO^^HjOH 3 have been determined by X-ray diffraction analysis. 1 and 2 are isomorphous with the central metal ion co-ordinated by the four nitrogen atoms of the ligand and six oxygen atoms of three chelating nitrate groups. In complex 3, besides the four nitrogen atoms of the ligand and three chlorine atoms, there is one H2O molecule co-ordinated. Conductivity studies on the [LnL(NO3)3]-C2H5OH complexes in methanol showed that two of the nitrate anions dissociate to give 2:1 electrolytes. Comparison of the emission lifetimes of the Eu3+ and Tb3t complexes in CH3OH and CD3OD gives the average value for q, the number of co-ordinated methanol molecules, of 3.4, suggesting the formation of species [LnL(NO3)(CH3OH)3][NO3]2. The emission quantum yields of the nitrate-coordinated series are substantially higher than those of the chloride series, as shown by luminescence studies in MeCN. The Royal Society of Chemistry 2000.

The dipodal ligands (Im) and (BIm) as well as complexes [FeLCl3] [L = Im (1) and BIm (2)] have been prepared and studied using spectroscopic techniques. The magnetic moment, IR, electronic (ligand field), FAB-mass and NMR spectral data indicate a hexa-coordinate geometry around high-spin state Fe3+ where the ligands coordinate as a tridentate [N,N,N] chelating agent. 57Fe-Moessbauer spectral data confirmed the presence of a ligand asymmetry around Fe3+ in a high-spin state electronic configuration (t2g3,eg2, S = 5/2) with nuclear transition Fe(±3/2 → ±1/2) exhibiting Kramer's double degeneracy. The molecular computations provided the optimum energy perspective plots for the molecular geometries giving the important structural data. Crown Copyright

Abstract: In the present work, a series of bisbenzazole derivatives were designed and synthesized as antiproliferative agents. The antiproliferative activity of these compounds was investigated using MTT assay. Bisbenzazole derivatives showed significant antiproliferative activity against all the four tested cancer cell lines. Among the various bisbenzazole derivatives, bisbenzoxazole derivatives exhibited the most promising anticancer activity followed by bisbenzimidazole and bisbenzothiazole derivatives. All the derivatives were found to be less toxic as compared to methotrexate (positive control) in normal human cells, indicating selective and efficient antiproliferative activity of these bisbenzazole derivatives. The structure–activity relationships of heteroaromatic systems and linkers present in bisbenzazole derivatives were analyzed in detail. In silico ADMET prediction revealed that bisbenzazole is a drug-like small molecule with a favorable safety profile. Compound 31 is a potential antiproliferative hit compound that exhibits unique cytotoxic activity distinct from methotrexate. Graphic abstract: Twenty-one bisbenzoxazole derivatives have been designed synthesized and evaluated to be an antiproliferative activity against four human tumor cell lines.[Figure not available: see fulltext.]

In an attempt to design and synthesize a potent class of antimicrobials, 1,2-phenylenediamine derivatives were reacted with various aliphatic and heteroaliphatic dicarboxylic acids to generate a small library of 26 head-to-head bisbenzimidazole compounds (16 – 42) using the polyphosphoric acid method. These compounds were screened for their antibacterial activity and their antifungal activity. Compound 25 showed maximum potency against both Gram-positive and Gram-negative bacterial strains with minimum inhibitory concentration (MIC) values in the range of 7.81 – 31.25 μg/mL. In particular, it showed the maximum MIC values of 7.81 μg/mL against Gram-negative bacteria, which was four-fold more active than the standard drug ampicillin (MIC = 32.25 μg/mL). Compound 19 was found to be the most active against S. aureus with a MIC value of 3.90 μg/mL, whereas the remaining compounds showed only low-to-moderate activity. Furthermore, all compounds exhibited low activity against all fungal strains in comparison to the standard drug fluconazole. I addition, pharmacophore hypotheses were generated to analyze structure–activity relationships between the molecular structures and antimicrobial activities on E. coli. This pharmacophore model can be useful in order to design new antimicrobial drugs. It can be suggested that the substitution of a phenyl ring at the 5/6 and 5′/6′ positions in symmetric bisbenzimidazole derivatives produces compounds with promising antimicrobial activity.

A method of promoting growth in a photosynthetic organism comprising treating the photosynthetic organism with a metal complex or a precursor thereof, wherein the metal complex comprises a metal selected from the group consisting of zinc (Zn), cobalt (Co), copper (Cu), nickel (Ni) and iron (Fe), and a ligand, which is a bidentate or tridentate ligand. Metal complexes and their ligands are also described.

Reactions of 2,6-bis(benzimidazol-2-yl)pyridine (L1), 2,6-bis(benzoxazol-2-yl)pyridine (L2), and 2,6-bis(benzothiazol-2-yl)pyridine (L3) with [Pd(NCMe)2Cl2] in the presence of NaBF4 afforded the corresponding Pd(II) complexes, [Pd(L1)Cl]BF4, PdL1; [Pd(L2)Cl]BF4, PdL2; [Pd(L3)Cl]BF4, PdL3; respectively, while reaction of bis[(1H-benzimidazol-2-yl)methyl]amine (L4) with [Pd(NCMe)2Cl2] afforded complex [Pd(L4)Cl]Cl, PdL4. Characterisation of the complexes was accomplished using NMR, IR, MS, elemental analyses and single crystal X-ray crystallography. Ligand substitution kinetics of these complexes by biological nucleophiles thiourea (Tu), L-methionine (L-Met) and guanosine 5′-diphosphate disodium salt (5-GMP) were examined under pseudo-first order conditions. The reactivity of the complexes decreased in the order: PdL1 > PdL2 > PdL3 > PdL4, ascribed to electronic effects. Density functional theory (DFT) supported this trend. Studies of interaction of the Pd(II) complexes with calf thymus DNA (CT-DNA) revealed strong binding affinities via intercalative binding mode. Molecular docking studies established associative non-covalent interactions between the Pd complexes and DNA. The in vitro cytotoxic activities of PdL1–PdL4 were assessed in cancer cell lines HeLa and MRC5-SV2 and a normal cell line MRC-5, using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. PdL1 exhibited cytotoxic potency and selectivity against HeLa cell that was comparable to cisplatin's. Complex PdL1, unlike cisplatin, did not significantly induce caspase-dependent apoptosis.

Abstract: A novel water-soluble carboxylate-bridged copper(II) coordination polymer, Cu-BIG was formed by the reaction of Cu(ClO4)2·6H2O and tridentate benzimidazole-glycine conjugate ligand, 2-((1H-benzimidazol-2-yl)methylamino) acetic acid, BIGH and its structure has been determined by IR, UV, powder XRD, VSM, CV, TGA, DTA, EPR and single crystal X-ray diffraction. Crystallographic studies indicate it to be a coordination polymer with Pī Space group. The asymmetric unit of complex contains two Cu(II) ions with elongated square pyramid geometry. The axial positions of the Cu(II) atoms are occupied by the carbonyl oxygen of the carboxylate group with the bond distances Cu (1) –O(5)axial,2.28?, and Cu (2) –O(2)axial,2.26?. The two Cu(II) are connected through the carboxylic group present in BIGH, which provides electron mobilisation in the molecule and hence results in the soft ferromagnetic polymer. An in vitro antibacterial activity study of BIGH and Cu-BIG showed moderate activity against Bacillus subtilis. The DNA binding studies showed the interaction of Cu-BIG with CT-DNA. Graphical Abstract: Synopsis: A water soluble ferromagnetic carboxylate-bridged copper(II) coordination polymer, Cu-BIG was formed by the reaction of Cu(ClO4)2·6H2O and tridentate benzimidazole-glycine conjugate ligand, 2-((1H-benzimidazol-2-yl)methylamino) acetic acid. [Figure not available: see fulltext.].

The invention discloses a multi-benzimidazole complex, and a preparation method and an application thereof. A required ligand multi-benzimidazole compound is synthesized with polybasic amine carboxylic acid or dicarboxylic acid and o-phenylenediamine as starting materials; the ligand multi-benzimidazole compound is subjected to a reaction with CuCl2, Cu(NO3)2 or Cu(ClO4)2 to synthesize the multi-benzimidazole complex. The multi-benzimidazole complex can be used as a stimulant of a copper-zinc superoxide oxidase (SOD1) and has an effect of improving the drought stress resistant ability of plants.

We have previously investigated cis/trans isomerization processes in phenoxido-bridged mixed-valent FeIIFeIII complexes that contain either one aniline or one anilide ligand. In this work, we compare the properties of similar complexes bearing one terminal protic ligand, either aniline or 1H-benzimidazole. Whatever the ligand, 1H NMR spectroscopy clearly evidences that the complexes are present in CH3CN as a mixture of cis- and trans-isomers in a close to 1:1 ratio. We show here that addition of NEt3 indeed allows the deprotonation of these ligands, the resulting complexes bearing either anilide or benzimidazolide that are coordinated to the ferric site. The latter are singular examples of a high-spin ferric ion coordinated to a benzimidazolide ligand. Whereas the trans-isomer of the anilide complex is the overwhelming species, benzimidazolide species are mixtures of cis- and trans-isomers in equal proportions. Moreover, cyclic voltammametry studies show that FeIIIFeIII complexes with 1H-benzimidazole are more stable than their aniline counterparts, whereas the reverse is observed for the deprotonated species. (Graph Presented).

1-(1H-Benzimidazol-2-yl)-N-(1H-benzimidazol-2-ylmethyl)methanamine (abb) and 2-(1H-benzimidazol-2-ylmethylsulfanylmethyl)-1H-benzimidazole (tbb) have been prepared and characterized by elemental analysis. These bis(benzimidazoles) have been further used in combination with trithiocyanuric acid for the preparation of complexes. The crystal and molecular structures of two of them have been solved. Each nickel atom in the structure of trinuclear complex [Ni3(abb)3(H2O)3(μ-ttc)](ClO4)3?3H2O?EtOH (1), where ttcH3 = trithiocyanuric acid, is coordinated with three N atoms of abb, the N,S donor set of ttc anion and an oxygen of a water molecule. The crystal of [(tbbH2)(ttcH2)2(ttcH3)(H2O)] (2) is composed of a protonated bis(benzimidazole), two ttcH2 anions, ttcH3 and water. The structure is stabilized by a network of hydrogen bonds. These compounds were primarily synthesized for their potential antimicrobial activity and hence their possible use in the treatment of infections caused by bacteria or yeasts (fungi). The antimicrobial and antifungal activity of the prepared compounds have been evaluated on a wide spectrum of bacterial and yeast strains and clinical specimens isolated from patients with infectious wounds and the best antimicrobial properties were observed in strains after the use of ligand abb and complex 1, when at least 80% growth inhibition was achieved.

A series of bis(benzimidazole)-based cobalt(II) dichloride complexes containing a range of different central donors has been synthesized and characterized. The nature of the central donor affects the binding of the ligand to the cobalt centre and determin

Ligands useful for promoting copper-catalyzed azide-alkyne cycloaddition reactions comprise a compound represented by structural Formula (I) as described in the specification, wherein in Formula (I) Z1 is a nitrogen-containing heterocyclic group or a group represented by the formula : Y1-(CH2)c-Y2-(CH2)d-Y3-CH2-N(CH2Z4)(CH2Z5), where Y1 is -E1-C(O)O-, -E1-C(O)NH-, -E1-, or a covalent bond; Y2 is a covalent bond, -CH=CH-, or a 1,4-(1,2,3-triazolyl) group; Y3 is -OC(O)-E2-, -NHC(O)-E2-, -E2-, or a covalent bond; each of E1 and E2 is a benzimidazolyl group attached at the 1 and 2 positions; each of c and d is independently 1, 2, 3, 4, or 5; each of Z2, Z3, Z4 and Z5 is a nitrogen-containing heterocyclic group including a substituent X1 and optionally including a substituent (CH2)n-R1, and Y1, Y2, Y3, X1, R1, c, d and n are each as defined in the specification.

Tris(2-benzimidazolylmethyl)amines have been found to be superior accelerating ligands for the copper(I)-catalyzed azide-alkyne cycloaddition reaction. Candidates bearing different benzimidazole N-substituents as well as benzothiazole and pyridyl ligand a

A polymerisation catalyst comprising (1) a transition metal compound of Formula A, and optionally (2) an activating quantity of a Lewis acid activator, Formula (A), wherein Z is a five-membered heterocyclic group containing at least one carbon atom, at least one nitrogen atom and at least one other hetero atom selected from nitrogen, sulphur and oxygen, the remaining atoms in the ring being nitrogen or carbon; M is a metal from Group 3 to 11 of the Periodic Table or a lanthanide metal; E1 and E2 are divalent groups from (i) aliphatic hydrocarbon, (ii) alicyclic hydrocarbon, (iii) aromatic hydrocarbon, (iv) alkyl substituted aromatic hydrocarbon (v) heterocyclic groups and (vi) heterosubstituted derivatives of groups (i) to (v); D′ and D2 are donor groups; X is an anionic group, L is a neutral donor group; n=m=zero or 1; y and z are zero or integers. The catalysts are useful for polymerising or oligomerising 1-olefins.

Synthetic procedures are described for obtaining various multidentate ligands incorporating benzimidazole moieties.The benzimidazoles were obtained by the condensation of acids with o-phenylenediamines.Syntheses are reported for N,N-bis(1-methylbenzimidazol-2-ylmethyl)amine (2), N,N'-bis(1-methylbenzimidazol-2-ylethyl)ethylenediamine (5), N,N,N',N'-tetrakis(benzimidazol-2-ylmethyl)-1,2-diaminocyclohexane (6), N,N,N',N'-tetrakis(4-methylbenzimidazol-2-ylmethyl)-1,2-diaminocyclohexane (7), HOOC-(CH2)m-S-CH2-CH2-S-(CH2)n-S-Ch2-CH2-S-(CH2)m-COOH , BzIm-(CH2)m-S-CH2-CH2-S-(CH2)n-S-CH2-CH2-S-(CH2)m-BzIm , HOOC-CH2-S-(CH2-CH2-S)4-CH2-COOH (15) and BzIm-CH2-S-(CH2-CH2-S)4-CH2-BzIm (16).