Coordination compounds of Co(II), Ni(II) and Cu(II) with capric acid hydrazide

The reaction of aquo-ethanolic solutions of Co(II), Ni(II) and Cu(II) salts and ethanolic solution of capric acid hydrazide (L) yielded paramagnetic, high-spin bis- and tris(ligand) chelate complexes. The tris(ligand) complexes, [ML ₃]X ₂·nH₂O [M=Co(II), Ni(II);X=NO ₃ ^– , ClO ₄ ^– , 1/2SO ₄ ^2– ], have an octahedral structure formed on account of the bidentate (NO) coordination of three neutral hydrazide molecules. In the bis(ligand) complexes,ML ₂(NCS)₂ [M=Co(II), Ni(II)] and CuL ₂ X ₂·nH₂O (X=NO ₃ ^– , ClO ₄ ^– and 1/2SO ₄ ^2– ), the oxoanions and NCS^– take also part in coordination. The complexes have been characterized by elemental analysis, IR spectra, magnetic measurements, molar conductivity and TG analysis.

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Caprinsäurehydrazid-Komplexe von Co(II), Ni(II) und Cu(II)

Zusammenfassung Durch die Reaktion von wäßrig-ethanolischen Lösungen von Co(II)-, Ni(II)-und Cu(II)-Salzen mit einer ethanolischen Lösung von Caprinsäurehydrazid (L) wurden paramagnetische high-spin Bis- und Tris-Ligand-Chelatkomplexe erhalten. Tris-Ligand-Komplexe des Typs [ML ₃ X ₂·nH₂O [M=Co(II), Ni(II);X=NO ₃ ^– , ClO ₄ ^– , 1/2SO ₄ ^2– ], die eine oktaedrische Struktur besitzen, entstehen durch die Koordination von drei neutralen zweizähnigen (NO)-Hydrazidmolekülen. Bei den Bis-Ligand-KomplexenML ₂(NCS)₂ [M=Co(II), Ni(II)], sowie bei den Bis-Ligand-Komplexen CuL ₂ X ₂·nH₂O (X=NO ₃ ^– , ClO ₄ ^– , 1/2SO ₄ ^2– ) nehmen bei der Koordination außer Hydrazid auch die Säurereste teil. Die Komplexe wurden durch Elementaranalyse, IR-Spektren, magnetische Messungen, molare Leitfähigkeit und TG-Analysen charakterisiert.

     

Design,synthesis, characterization and antibacterial properties of copper(II) complexes with chromone‐derived compounds

A new series of six chromone‐derived compounds and their Cu(II) complexes was synthesized and characterized by their physical, spectral and analytical data The elemental analysis data of the complexes agree well with the proposed composition of the compounds, which were found to be dimeric in nature with two hydrazine molecules bridging the two copper atoms through coordination. The ligands and their Cu(II) complexes were screened for their in‐vitro antibacterial activity against four Gram‐negative (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Shigella flexneri) and two Gram‐positive (Bacillus subtilis, Staphylococcus aureus) bacterial strains by the agar‐well diffusion method. The ligands were found to exhibit either no or low to moderate activities against one or more of the bacterial species, whereas all the metal complexes exhibited moderate to high activities against different bacterial species. The ligands which were inactive before complexation turned active and less active ones became more active upon coordination with copper ions. Overall, the complexes 7–12 showed comparatively much higher activities than the ligands. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis,characterization, molecular modeling,and thermal analyses of bioactive Co(II) and Cu(II) complexes with diacetylmonoxime and different amines

Condensation of diacetylmonoxime with 2-amino-5-mercapto-1,3,4-thiadiazole, 2-amino-1,3,4-thiadiazole or 3-amino-5-methylisoxazole in the presence of Co(II) and Cu(II) salts with different anions produced nine complexes. The synthesized complexes have been characterized by elemental analyses, molar conductivities, thermal analyses, magnetic moments, IR, electron spin resonance, and UV-Vis spectral studies. The spectral data show that sulfur, oxygen, and nitrogen participate in chelation with the metal ions. The complexes are tetrahedral, octahedral, or square planar based on the amine used and the nature of anion. Molar conductance measurements of the complexes in DMF indicate non-electrolytes. CS Chem 3-D Ultra Molecular Modeling and Analysis Program has been used for optimization of the molecular structures of some complexes. In vitro cytotoxicities of the complexes were tested against different carcinoma cell lines. Antimicrobial activities of the complexes were screened against Gram-positive (Staphylococcus aureus), Gram negative bacteria (Escherichia coli), and fungal species (Aspergillus flavus, Candida albicans, and Microsporum canis).     

Hetero-binuclear chelates of Mn(II), Co(II) and Cu(II) o-cresolphthalein complexonates with other metal ions

Heterobinuclear metal chelates of Mn²⁺, Co²⁺ or Cu²⁺ and some transition metal ions with o-cresolphthalein complexone have been prepared and characterized. Elemental analyses are in agreement with proposed formulae. Thermal analyses (TGA and DTA) were used to determine the degradation products; some thermodynamic parameters were calculated. IR and UV-Vis spectra identified the mode of bonding between the metal ions and the ligand as well as its geometry. Magnetic moment determination and ESR spectra of the heterobinuclear complex revealed some antiferromagnetic interaction between the metal ions, which depends mainly on the two metal ions forming the chelate. Electrochemical studies of the complexes [DC-polarography and cyclic voltammetry (CV)] confirmed the existence and the nature of the metal ions in the chelate.     

Crystal structure of bis(l-arginine)copper(II) hexachlorodimercurate, [Cu(l-Arg)2]Hg2Cl6

By means of X-ray diffraction the chain structure of [Cu(l-Arg)₂]Hg₂Cl₆ (monoclinic, a = 10.2348(9) Å, b = 9.1386(7) Å, c = 14.8521(14) Å, β = 97.455(11)°, space group P2₁) is established. The chains are formed by square-planar [Cu(l-Arg)₂]²⁺ cations of the type trans-[Cu(N)₂(O)₂] (l-Arg is the zwitter-ion of arginine; Cu-N 1.992 Å and 1.938(6) Å, Cu-O 1.953 Å and 1.967(4) Å) that are bonded to two adjacent binuclear [Cl₂Hg(μ-Cl)₂HgCl₂]^2? ions through its clorine atoms Cl (Hg-Cl bonds are within 2.34–2.78 Å). With these two additional Cu…Cl contacts Cu adopts the geometry of an elongated octahedron with two apical Cl (Cu-Cl 2.961 Å and 3.064(3) Å).     

New Ni(II)Cu(II)Ni(II) trinuclear complexes with an 5=3/2 high-spin ground

Four new heterotrinuclear complexes have been synthesized and characterized, namely {[Ni(L)₂]₂[Cu(opba)]}(ClO₄)₂, where opba denotes o-phenylenebis(oxamato) and L stands for 1,10-phenanthroline(phen) (1), 5-nitro-l,10-phenanthroline(NO₂-phen) (2), 2,2′-bipyridyl(bpy) (S) and 4,4′-dimethyl-2,2′-bipyridyl(Me₂bpy) (4). The temperature dependence of the magnetic susceptibility of {[Ni(phen)₂]₂[Cu(opba)]}(ClO₄)₂3H₂O has been studied in the 4–300 K range, giving the exchange integral J—109 cm^?1. The HMT vs. T plot exhibits a minimum at about 100 K, characteristic of this kind of coupled polymetallic complex with an irregular spin-state structure.     

大环金属铜(II)、镍(II)配合物的模板合成与晶体结构

用模板法合成了1个大环金属铜(II)配合物[CuLCl₂]·3H₂O (1)和3个大环金属镍(II)配合物[NiLCl₂] (2)，[NiL](ClO₄)₂ (3)和[NiLH₂](ClO₄)₄ (4)(L=3,10-二乙基-1，3，5，8，10，12-六氮杂十四烷)，通过X-射线衍射单晶结构分析测定了它们的晶体结构。晶体结构显示：配合物1和2的金属离子与大环配体的4个氮原子及大环平面轴向的2个氯离子以八面体配位方式配位；配合物3和4的金属离子与大环配体的4个氮原子以平面正方形配位方式配位，配合物4的侧链氮原子的质子化导致侧链结构翻转，使得其侧链与大环平面共面。     

New heterocyclic metallomesogens: synthesis,mesomorphic and thermal behaviours of Cu(II) complexes with 1,2,3-triazole-based Schiff bases ligands

Two series of new Cu(II) complexes derived from the reaction of copper acetate with the non-linear 1,2,3-triazole-based Schiff bases have successfully been synthesised. The structures of the ligands and its complexes were elucidated by elemental analysis, FT-IR, ¹H-NMR and UV–visible spectroscopic techniques. The differential scanning calorimetry and polarizing optical microscopy supported the anisotropic properties of uncoordinated ligands in which the focal conic fan-shaped texture and/or broken fan-shaped texture characteristics of respective SmA and SmC phases were recorded. However, not all of their corresponding Cu(II) complexes are mesogenic. Although the iodo-substituted ligands with even parity C₁₀H₂₉ to C₁₄H₃₃ are non-stable and exhibit SmA phase which is not reproducible, the ultimate Cu(II) complexes show exclusively stable SmA phase. This observation can be ascribed to the enhanced colinearity and molecular anisotropic by the presence of Cu-N and Cu-O coordination modes. On the other hand, the comparison studies show that different positions of ortho-hydroxyl group affect the mesomorphic and thermal behaviour of ligands and Cu(II) complexes.     

A study on synthesis and thermal,spectral and biological properties of carboxylato-Mg(II) and carboxylato-Cu(II) complexes with bioactive ligands

Summary Synthesis, elemental (CHN), spectral (FTIR), thermogravimetry (TG), differential thermal analysis (DTA) and complexometric titration have been applied to the investigation of the thermal behavior and structure of the complexes: Mg(ac)₂(mpc)₃·3H₂O(I), Mg(Clac)₂(mpc)₂·3H₂O(II), Mg(Cl₂ac)₂(mpc)₂·3H₂O(III), Mg(Cl₃ac)₂(mpc)₂·3H₂O(IV) and [Cu(ac)₂(mpc)]₂·3H₂O(V) (ac=CH₃COO^-, Clac=ClCH₂COO^-, Cl₂ac=Cl₂CHCOO^-, Cl₃ac=Cl₃CCOO^- and mpc=methyl-3-pyridyl carbamate). Thermal decomposition of these complexes is a multi-stage processes. The composition of the complexes and the solid state intermediate and resultant products of thermolysis had been identified by means of elemental analysis and complexometric titration. The possible scheme of decomposition of the complexes is suggested. Heating the complexes first resulted in a release of water molecules. The TG results show that the loss of the volatile ligand (mpc) occurs in one step for complexes II, IV and V, and in two steps for complexes I and III. The final solid product of thermal decomposition was MgO or CuO. The thermal stability of the complexes can be ordered in the sequence: I=II<IV<III<V. Mpc was coordinated to Mg(II) or Cu(II) through the nitrogen atom of its heterocyclic ring. IR data suggest to a unidentate coordination of carboxylates to magnesium or copper n complexes I-V. The preliminary studies have shown that the complexes do have antimicrobial activities against bacteria, yeasts and/or fungi. The highest antimicrobial activities were manifested by the complex V.     

Complexes of substituted dipyridylpyridazines with palladium(II) and platinum(II)

Reactions of 3,6-bis(2′-pyridyl)pyridazine derivatives (n-dppn)¶ ¶For the n-dppn ligands, n stands for the size of the cyclic aliphatic ring on positions 4 and 5 of the pyridazine ring, n?=?5, 6, 8, and 12. with MX₂(PhCN)₂ (M?=?Pd, Pt; X?=?Cl,?Br) have been investigated. The new complexes cis-[PdCl₂(n-dppn)] (n?=?5,?6,?8,?12), cis-[PtCl₂(n-dppn)]?·?H₂O (n?=?5,?6), cis-[PtCl₂(8-dppn)] and cis-[PtBr₂(5-dppn)] have been characterized by elemental analyses, conductivity measurements, infrared, electronic and ¹H-NMR spectra.     

Synthesis,spectroscopy and thermal analysis of copper(II) hydrazone complexes

The chelating behavior of some hydrazones towards Cu(II) has been investigated. The isolated complexes were characterized by elemental analysis, magnetic moment, spectra (electronic, IR and ms) and thermal measurements. The IR spectra showed that the ligands are deprotonated in the complexes as bidentate, tridentate and binegative tridentate. Protonation constants of the ligands and the stability constants of their Cu(II) complexes were calculated. Square-planar, square-pyramidal, tetrahedral and/or distorted octahedral structures are proposed. The TGA data help to confirm the chemical formula of the complexes and indicated the steps of their thermal degradations.     

Thermogravimetric investigation of thermal decomposition of copper(II) complexes with methylpyrido[2,3-d]imidazole derivatives

Solid-state complexes with the formulae CuL _x X₂·nH₂O, wereL=2-methyl-, 5-methyl-, or 7-methylpyrido[2,3-d]imidazole,X=NO ₃ ^– or Cl^–,x=2 or 3, andn=1 or 2, were subjected to thermogravimetric analyses. The kinetic parameters were calculated according to the Coats-Redfern method. Reactions paths are proposed and their agreement with the data obtained from TG curves is checked.The authors thank Dr. W. Surga for XRD analyses, and Dr. B. Kowalczyk and Dr. M. Czerwinski from the Pedagogical University in Czestochowa for providing access to the computer application allowing calculation of the kinetic parameters.     

Synthesis,characterization, electrochemical behavior and antioxidant activity of new copper(II) coordination compounds with curcumin derivatives

Five new copper(II) coordination compounds were prepared by template synthesis, using curcumin, 2-hydrazinobenzothiazole and metal salt (copper chloride, bromide, acetate and nitrate) in 1:2:1 and 1:2:2 molar ratio. The complexes were characterized by elemental and thermogravimetric analysis, IR, UV–Vis and mass spectroscopic methods and cyclic voltammetric studies. On the basis of physico-chemical measurements the following formulae have been assigned to the complexes: [Cu(H₂L)(H₂O)₂]Cl₂·H₂O, [CuL]·H₂O, [Cu(H₂L)(H₂O)Br]Br·5H₂O, [Cu₂L(H₂O)₄](NO₃)₂·2H₂O and [Cu₂(H₂L)(NO₃)₄]·H₂O, where H₂L is the hydrazone ligand formed in the reaction conditions. Metal complexes were tested for antioxidant activity by photochemiluminescence and this activity was quantified by comparison with TROLOX®, as standard. The results show that all complexes are more potent antioxidant agents than curcumin.     

Synthesis and characterization of potassium 1,3-bis(N-methylpiperazino)propan-2-O-xanthate and the complexes of Co(II), Ni(II) and Cu(I) ions

Potassium 1,3-bis(N-methyl piperazino)propan-2-O-xanthate (LK), and its complexes with Co(II), Ni(II) and Cu(I) ions have been prepared and characterized as [CoL₂(H₂O)₂], [NiL₂(H₂O)₂]·2H₂O and CuL·2H₂O by FT-IR, ¹H and ¹³C?NMR spectroscopies, elemental analyses, magnetic susceptibility and TGA techniques.     

Redox-active antifungal cobalt(II) and copper(II) complexes with sterically hindered o-aminophenol derivatives

Co(II) complexes with 4,6-di(tert-butyl)-2-aminophenol (HL^I) and 2-anilino-4,6-di(tert-butyl)phenol (HL^II) have been synthesized and characterized by means of physico-chemical methods. The compounds HL^I and HL^II coordinate in their singly deprotonated forms and behave as bidentate O,N-coordinated ligands; their low-spin Co(II) complexes are characterized by CoN₂O₂ coordination modes and square planar geometry. Both the free ligands and their Co(II) and Cu(II) complexes (we have produced and characterized the latter before) exhibit a pronounced antifungal activity against Aspergillus niger, Fusarium spp., Mucor spp., Penicillium lividum, Botrytis cinerea, Alternaria alternata, Sclerotinia sclerotiorum, Monilia spp., which in a number of cases is comparable with that of Nystatin and Terbinafine or even higher. The reducing properties of the ligands and their metal(II) complexes, as well as their antifungal activities, were found to decrease in the order: Cu(L^I)₂ > Cu(L^II)₂ ? Co(L^I)₂ > Co(L^II)₂ > HL^I > HL^II.     

TG,DTA and electrical conductance properties of some Cu(II) AND Mn(II) bisazo- dianils complexes

The TG and DTA of a new series of Mn(II) and Cu(II) complexes with a number of newly prepared bisazo-dianil ligands were studied in the temperature range (20-700°C). The TG and DTG curves display to main steps, the first one within the temperature range (25-330°C) correspond to the elimination of water or and ethanol from the complexes. The second step within the range (350-625°C) is due to the decomposition of the complexes yielding the metal oxides as the final product. The rate constants of the dehydration and decomposition reactions were determined, from which some kinetic parameters were evaluated. The DTA curves show that the dehydration of the metal complexes is an endothermic reaction. In all cases the anhydrous metal complexes undergo exothermic decomposition reactions to give the metal oxide. The thermodynamic parameters (ΔE, ΔH, ΔS, ΔG) for the occurring processes are calculated. The electrical conductivities of the solid complexes were measured and the activation energy of the complex and its free ligand are also calculated. This revised version was published online in August 2006 with corrections to the Cover Date.     

Comparative study of Cu(II) catalytic sites immobilized onto different polymeric supports

The catalysts with copper(II) ions stabilized onto different polymeric matrixes are prepared on either bulk (Cu/chitosan, Cu/polyethyleneimine-polyacrylic acid (PPA), and Cu-diiminate-impregnated polystyrene, polyarylate, or polymethylmethacrylate) or composite supports (egg-shell type Cu/chitosan/SiO₂ and Cu/PPA/SiO₂). The morphology of the samples and peculiarities of Cu(II) cationic sites are studied by SEM and ESR methods, and the catalyst activities are compared in oxidation of o- and p-dihydroxybenzenes by air in water. The catalytic activity of Cu(II) centers is governed by the coordination of isolated copper ions: for the most active catalysts, i.e., Cu/chitosan and Cu/PPA, the symmetry of isolated Cu²⁺-sites approximates a coordinatively unsaturated square-planar structure. At the same time, accessibility of active sites to water differs for different polymers, so the contribution of hydrophilicity to the reaction pattern cannot be excluded. Redox transformations of the active sites in the course of catalytic tests do not cause copper leaching from the polymer matrix. The binary composite systems with a film of low-loaded hydrofilic Cu-polymer supported on macroporous SiO₂ demonstrate substantially higher activity in oxidation of hydroquinone and 3,4-dihydroxyphenylalanine, as compared with the bulk Cu/polymer samples. In turn, the specific activity of Cu/chitosan/SiO₂ exceeds significantly that of Cu/PPA/SiO₂ due to stabilization of a thinner and more uniform film of chitosan at the surface of silica.     

Synthesis and characterization of a new pyrrolidine containing sulfur ligand and the transition metal complexes of Co(II), Ni(II) and Cu(I)

Potassium 1,3-dipyrrolidinopropan-2-O-xanthate (LK), and its complexes with Co(II), Ni(II) and Cu(I) have been prepared and characterized as [CoL₂(H₂O)₂]?·?2H₂O, [NiL₂(H₂O)₂] and CuL?·?2H₂O by FT-IR, ¹H and ¹³C NMR spectroscopies, elemental analyses, magnetic susceptibility and TGA techniques.     

Synthesis and characterization of a tetramethyl furanone functionalized diiminedioxime,a potential ligand for Cu radiopharmaceuticals,and its copper(II) and nickel(II) complexes

As part of our on-going effort to develop ⁶⁴Cu-based radiopharmaceuticals for PET (positron emission tomography) imaging of multidrug resistance in cancer, we prepared a tetramethylfuranone-functionalized diiminedioxime ligand, TMFPreH (TMFPreH = 4-[3-(4-hydroxyimino-2,2,5,5-dimethyl-dihydro-furan-3-ylideneamino)-propylimino]-2,2,5,5-tetramethyl-dihydrofuran-3(2H)-one oxime) and its Cu(II) and Ni(II) complexes. When the copper(II) complex was prepared from Cu(ClO₄)₂ in ethanol, it was isolated as a Cu(II)-bridged dimer, but when it was prepared from Cu(OAc)₂ and heated in acetone, an unusual example of an acetone adduct of the ligand is formed by reduction of one of the imine double bonds by the solvent. The Ni(II) complex is square pyramidal with the perchlorate counterion at the apex.     

Bioactive Co(II), Ni(II), and Cu(II) Complexes Containing a Tridentate Sulfathiazole-Based (ONN) Schiff Base

New Co(II), Ni(II), and Cu(II) complexes were synthesized with the Schiff base ligand obtained by the condensation of sulfathiazole with salicylaldehyde. Their characterization was performed by elemental analysis, molar conductance, spectroscopic techniques (IR, diffuse reflectance and UV–Vis–NIR), magnetic moments, thermal analysis, and calorimetry (thermogravimetry/derivative thermogravimetry/differential scanning calorimetry), while their morphological and crystal systems were explained on the basis of powder X-ray diffraction results. The IR data indicated that the Schiff base ligand is tridentate coordinated to the metallic ion with two N atoms from azomethine group and thiazole ring and one O atom from phenolic group. The composition of the complexes was found to be of the [ML₂]∙nH₂O (M = Co, n = 1.5 (1); M = Ni, n = 1 (2); M = Cu, n = 4.5 (3)) type, having an octahedral geometry for the Co(II) and Ni(II) complexes and a tetragonally distorted octahedral geometry for the Cu(II) complex. The presence of lattice water molecules was confirmed by thermal analysis. XRD analysis evidenced the polycrystalline nature of the powders, with a monoclinic structure. The unit cell volume of the complexes was found to increase in the order of (2) < (1) < (3). SEM evidenced hard agglomerates with micrometric-range sizes for all the investigated samples (ligand and complexes). EDS analysis showed that the N:S and N:M atomic ratios were close to the theoretical ones (1.5 and 6.0, respectively). The geometric and electronic structures of the Schiff base ligand 4-((2-hydroxybenzylidene) amino)-N-(thiazol-2-yl) benzenesulfonamide (HL) was computationally investigated by the density functional theory (DFT) method. The predictive molecular properties of the chemical reactivity of the HL and Cu(II) complex were determined by a DFT calculation. The Schiff base and its metal complexes were tested against some bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis). The results indicated that the antibacterial activity of all metal complexes is better than that of the Schiff base.