15709-76-9

Three new transition metal complexes of the type ML2 (where M = Ni(II), Co(II) or Cu(II); HL = N′-[phenyl(pyridin-2-yl)methylidene]furan- 2-carbohydrazide]) have been prepared by treating [NiCl2(PPh 3)2], [CoCl2(PPh3)2] or [CuCl2(PPh3)2] with N′-[phenyl(pyridin-2- yl)methylidene]furan-2-carbohydrazide derived from furoic acid hydrazide and 2-benzoyl pyridine wherein the hydrazone ligand (L) coordinated to the respective metal ions in 1:2 stoichiometry to mononuclear octahedral complex. The crystal structure of the complexes [NiL2] (1), [CoL2] (2) and [CuL2] (3) solved using single crystals revealed a distorted octahedral geometry around the metal ion involving the coordination of an azomethine nitrogen, a pyridine nitrogen and an enolic oxygen derived from deprotonation of the ligand. From the bioinorganic application point of view, a detailed work on the binding of the complexes 1, 2 and 3 with CT DNA as well as BSA was undertaken along with DNA cleavage. In vitro assay on the antioxidant activity of the above complexes and hydrazone ligand revealed that they possess significant antioxidant activity. However, among the newly synthesized hydrazone complexes, complex 3 having coordinated Cu2+ ion in its molecular structure exhibited superior activity in all the biological studies in comparison with the other two complexes possessing nickel and cobalt ions with same ligand (L).

The surface coordination chemistry of benzotriazole (BTAH) on a Cu electrode was investigated by electrochemical synthesis of surface complexes and in situ electrochemical surface-enhanced Raman spectroscopy (SERS) in nonaqueous solution. Two different surface complexes were prepared in solution with or without triphenylphosphane (PPh3). A new mixed-valence Cu-N cluster compound containing BTAH was synthesized by direct electrochemical oxidation of Cu in nonaqueous solutions with PPh3. The final product, Cu5Cl(BTA)5(PPh3)4 was crystallized and characterized by microanalysis and Raman spectroscopy together with X-ray crystallographic determinations. The complex crystallized in a monoclinic space group (P21/n) with lattice parameters α = 16.739(2) A, b = 18.919(2) A, c = 31.042(4) A, β = 103.194(3)°, V = 9571.0(19) A3, R1 = 0.0704, wR2 = 0.1643. The results showed that the complex was a pentanuclear compound. The central CuII atom is coordinated to four equatorial and one axial BTA - ligands to form a distorted tetragonal pyramidal coordination polyhedron, whereas each surrounding CuI ion is in a distorted tetrahedral environment. The in situ SERS studies revealed that the BTA - ion was coordinated to a Cu surface through its two N atoms of the triazole ring to form a surface polymer complex of [Cu(BTA)]n, which suppressed the dissolution and oxidation of Cu effectively. The introduction of PPh3 blocked the surface coordination of BTAH with the electrode, and a complex of BTA- and PPh3 with Cu was formed in the bulk solution. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.

Due to its design, trithiooxalat (trto) as a multidentate, chalcogen-rich ligand allows different coordination possibilities. In contrast to the corresponding dinuclear silver complex [(Ph3P)2Ag]2(trto), which is side-on(S,S′)/end-on(S′,S″) coordinated, the title complex is exclusively side-on (S,S′ and S″,O) coordinated involving the oxygen donor atom. [(Ph3P)2Cu]2(trto) crystallizes in the triclinic space group P1 (No. 2) with a = 10.195(2), b = 13.090(3), c = 13.450(3) A, α = 116.10(2)°, β = 90.10(2)°, γ = 101.49(2)°, and Z = 1. The bridging ligand with its nonsymmetrical donor atom set is disordered around the centre of symmetry (inversion centre). Johann Ambrosius Barth 1996.

Nine new copper complexes with the general formula [CuX(TPP)n(ATU)3-n] (where X = Cl, Br, and I, ATU = acetylthiourea, TPP = triphenylphosphine and n varies as 0, 1 and 2) were synthesized in a simple fashion, by changing the ratio of the ligands. The synthesized complexes were characterized by techniques, such as FT-IR and NMR spectroscopy, CHNS elemental analysis and single crystal X-ray technique. The XRD technique showed the monodentate behavior of TPP and ATU. The synthesized compounds were utilized in different biological assays, which showed anti-bacterial, anti-fungal, anti-lieshmanial, anti-oxidant and cytotoxic properties against brine shrimps. In parallel, molecular docking was carried out to decipher the binding conformation and chemical interactions of the compounds in the active binding pockets of biological drug targets against bacterial pathogens and lieshmanial parasite, as well as a cancer target. All these analyses revealed compounds [CuCl(TPP)(ATU)2] and [CuI(TPP)(ATU)2] to be the most effective molecules of the series. Molecular docking indicated that hydrogen bonding and hydrophobic pi-interactions play important role for the activities of complexes with ligands TPP/ATU ratio of 1/2.

The synthesis and the study of the molecular structure of a series of heteroleptic copper(I) compounds with triphenylphosphine and α-diimines presenting a varying degree of bulk at their chelating cite is reported. The most sterically crowded diimine acts as a monodentate ligand towards copper(I) promoting bridging of the halogen atom present in the metal coordination sphere and formation of a dimer. Evidence for this behavior is obtained from the electronic spectra and semiempirical quantum chemical calculations with MOPAC. Steric demands in all the studied compounds preclude coordination of silver(I) under similar reaction conditions.

Preparation of metastable solid-state materials is often hindered by the limitations of traditional solid-state chemistry, namely the high temperatures required to induce solid-state diffusion. Here, we present the formation of the metastable pyrite polym

A highly stereoselective alkyne semihydrogenation with copper(I) complexes is reported. Copper-N-heterocyclic carbene complex catalysts, bearing an intramolecular Cu-O bond, allow for the direct transfer of both hydrogen atoms from dihydrogen to the alkyn

A new series of geometrically different complexes containing ferrocenyl hydrazone ligands were synthesised by reacting suitable precursor complex [MCl2(PPh3)2] with the ligands HL1 or HL2 (where M = Cu(ii) or Ni(ii); HL1 = [Cp 2Fe(CHN-NH -CO- C6H5)] (1) and HL2 = [Cp2Fe(CHN-NH-CO-C5H4N)]) (2). The new complexes of the composition [Cu(L1)(PPh3)2], (3) [Cu(L2)(PPh3)2] (4), [Ni(L 1)2] (5) and [Ni(L2)2] (6) were characterised by various spectral studies. Among them, complexes 3 and 5 characterised by single crystal X-ray diffraction showed a distorted tetrahedral structure for the former with 1:1 metal-ligand stoichiometry, but a distorted square planar geometry with 1:2 metal-ligand stoichiometry in the case of the latter. Systematic biological investigations like DNA binding, DNA cleavage, protein binding, free radical scavenging and cytotoxicity activities were carried out using all the synthesised compounds and the results obtained were explained on the basis of structure-activity relationships. The binding constant (Kb) values of the synthesised compounds are found to be in the order of magnitude 103-105 M-1 and also they exhibit significant cleavage of supercoiled (SC) pUC19 DNA in the presence of H2O2 as co-oxidant. The conformational changes of bovine serum albumin (BSA) upon binding with the above complexes were also studied. In addition, concentration dependent free radical scavenging potential of all the synthesised compounds (1-6) was also carried out under in vitro conditions. Assays on the cytotoxicity of the above complexes against HeLa and A431 tumor cells and NIH 3T3 normal cells were also carried out.

Potential bidentate hydrazone ligands, HL1 (1) and HL 2 (2) prepared by the condensation of benzaldehyde or furfuraldehyde with benzhydrazide upon reaction with [CuCl2(PPh3) 2] yielded corresponding m

The tris(triphenylphosphine)copper(I) complexes [(PPh3) 3CuX] for X = Cl (1), Br (2), I (3), ClO4 (4), BF 4 (5), [(PPh3)3CuCl]·CH3CN (1a), [Cu(PPh3)3(CH3CN)]X for X = ClO 4 (6), BF4 (7), and [Cu(PPh3) 3(CH3CN)]X·CH3CN for X = SiF5 (8), PF6 (9) have been studied by solid state 31P CP/MAS NMR spectroscopy together with single crystal X-ray diffraction for compounds (6)-(9), the latter completing the availability of crystal structure data for the series. Compounds (1)-(5) form an isomorphous series in space group P3 (a ～ 19, c ～ 11 A) with three independent molecules in the unit cell, all disposed about 3-fold symmetry axes. Average values (with estimated standard deviations) for the P-Cu-P, P-Cu-X bond angles and Cu-P bond lengths in compounds (1)-(3) are 110.1(6)°, 108.8(6)° and 2.354(8) A and 115.2(6)°, 102.8(9)° and 2.306(9) A for compounds (4) and (5). For the acetonitrile solvated compound (1a), the corresponding parameters are 115(4)°,103(3)° and 2.309(3) A. The solid state 31P CP/MAS NMR quadrupole distortion parameters, dvCu, for (1)-(3) and (1a) are all less than 1 × 109 Hz2, despite the changes in donor properties of the halide in (1)-(3), and the coordination geometry of the P3CuX core in (1a). Change of anion to ClO 4- and BF4- in compounds (4) and (5) results in a significant increase of dvCu to 4.4-5.2 109 Hz2 and 5.2-6.0 × 109 Hz2, respectively. Compounds (6) and (7) crystallise as isomorphous [Cu(PPh3) 3(CH3CN)]X salts in space group Pbca, (a ～ 17.6, b ～22.3, c ～24.2 A), while compounds (8) and (9) crystallize as isomorphous acetonitrile solvated salts [Cu(PPh3)3(CH 3CN)]X·CH3CN in space group P1 (a ～ 10.5, b ～ 13.0, c ～19.5 A, a ～ 104, β ～ 104, γ ～ 94°). The P3CuN angular geometries in all four compounds are distorted from tetrahedral symmetry with average P-Cu-P, P-Cu-N angles and Cu-P bond lengths of 115(4)°, 103(4)° and 2.32(1) A, with dv Cu ranging between 1.3 and 2.5 × 109 Hz2. The solid state 29Si CP/MAS NMR spectrum of the pentafluorosilicate anion in compound (8) is also reported, affording 1J(29Si, 19F) = 146 Hz. The Royal Society of Chemistry 2005.

Reactions of copper alkoxide complexes Cu(OCH(CF3)2)(PPh3)3, Cu(OCHPh2)(PPH3)3, and [Cu(OPh)(PPh3)2]2 with HC≡CCOOR (R = Me, Et, tBu) give alkynyl copper complexes formulated as Cu2(C≡CCOOR)2(PPh3)3 (1, R = Me; 2, R = Et; 3, R = tBu). The 1H, 13C{1H}, and 31P{1H} NMR spectra agree with the structures containing two bridging alkynyl ligands that are coordinated to Cu(PPh3) and to Cu(PPh3)2 units. The copper alkoxide complexes react with alkynes HC≡CSiMe3, HC≡CPh, and HC≡CC6H4-p-Me to give alkynylcopper(I) complexes [Cu(C=CR′)(PPh3)]4 (4, R′ = SiMe3; 5, R′ = Ph; 6, R′ = C6H4-p-Me). X-ray crystallography of 4·Et2O reveals a molecular structure containing a cubane-like core composed of four copper(I) centers bridged by four alkynyl ligands, each of which is coordinated to three Cu centers as a μ3-η1:η1:η1-ligand. Complex 5 undergoes ligand substitution by HC≡CCOOEt in the presence of PPh3 to give 2. Complexes 1-6 react with PdCl2(PEt3)2 to cause alkynyl ligand transfer from Cu to Pd. Reactions of 1-3 with 0.5 equiv of PdCl2(PEt3)2 in the presence of PPh3 give trans-Pd(C≡CCOOR)2(PEt3)2 accompanied by formation of CuCl(PPh3)3. Complex 4 undergoes alkynyl ligand transfer to give trans-PdCl(C≡CSiMe3)(PEt3)2 exclusively, while similar reactions of 5 and 6 give mixtures of trans-Pd(C≡CAr)2(PEt3)2 and trans-PdCl(C≡CAr)(PEt3)2 (Ar = Ph, C6H4-p-Me).

The reaction of L2CuCl with Co(CO)4- or Co(CO)3PR3- leads to the formation of binuclear Cu-Co complexes. Solution infrared data indicates that these complexes contain a single Cu-Co bond with no CO-Cu interaction. The solid-state spectra were similar except for that of (tmed)CuCo(CO)4 which exhibits a low-frequency band at 1820 cm-1. A single-crystal structural analysis of this material was undertaken. The molecule [(CH3)2NCH2CH2N(CH3) 2]CuCo(CO)4 crystallizes in the orthorhombic space group Pna21 with a = 16.681 (3) ?, b = 8.797 (1) ?, and c = 9.994 (1) ?. Full-matrix least-squares refinement with anisotropic temperature factors for the non-hydrogen atoms and fixed, isotropic thermal parameters for the hydrogens have converged to R = 0.051 and Rw = 0.053 for the 862 observed reflections. The Cu and Co are bonded at a distance of 2.38 ?. One of the carbonyl groups asymmetrically bridges the Cu-Co bond; the three remaining carbonyls are terminally bonded to the Co atom. The tmed molecule functions as a bidentate ligand on the Cu, which exhibits nearly planar coordination.

The solution equilibria in benzene of arylphosphine complexes of the type LmCunXn (L = Ph3P, MePh2P; X = Cl, Br, I; m:n = 3:1, 4:2, 3:2, 2:2, 4:4) have been investigated by using UV spectrometry and vapor pressure osmometry. The halogen appears to have only a minor effect on the dissociation. A detailed analysis of the chloride complexes shows that ligand dissociation of the L3CuCl complexes is also accompanied by dimerization of the coordinately unsaturated copper(I) complexes through halogen bridging. However, the dimeric and tetrameric species formed by halogen bridging are found to be significant species in solution only when the ratio of L to CuCl is less than 3:1. An equilibria system is proposed with equilibrium constants derived from the modeling of the experimental data. The constants for the single ligand dissociation from (Ph3P)3CuCl and (MePh2P)3CuCl are 2 × 10-2 and 2 × 10-4, respectively. With the much greater dissociation of the Ph3P complex, the (Ph3P)2CuCl species is the dominant form in a benzene solution made from the solid-state (Ph3P)3CuCl complex. Solution profiles of different ratios of L to CuCl are generated to show how various species present in solution vary with concentration. The stability of the LmCunCln complexes (Ph3P ? MePh2P) toward ligand dissociation is attributed to greater steric interactions of Ph3P in comparison to MePh2P.