Synthesis,Characterization, Structural Description,Micellization Behavior,DNA Binding Study and Antioxidant Activity of 4, 5 and 6-Coordinated Copper(II) and Zinc(II) Complexes

Four mononuclear copper(II) and zinc(II) complexes were synthesized by the reaction of copper and zinc salts with 3,4-dichlorophenylactic acid, 2-bromophenylactic acid, biphenylacetic acid (O-donor ligand) and bipyridine (N-donor ligands) having the general formulae [(L)₂Cu(bp)(H₂O)] ( 1 ), [(BpA)₂Cu(bp)] ( 2 ), [(L)₂Zn(bp)(H₂O)] ( 3 ) and [(L*)₂Zn(bp)] ( 4 ) (L = 3,4-dichlorophenylacetate, L* = 2-bromophenylacetate bp = bipyridine, and BpA = biphenylacetate). Structures of all compounds were characterized through FT-IR spectroscopy and X-ray diffraction analysis. FT-IR spectra of all complexes confirmed the binding mode of Cu-O and Zn-O. XRD data revealed that complexes 1 – 3 exhibited distorted octahedral arrangement, whereas complex 4 has a distorted tetrahedral environment. Micellization behavior was examined with anionic surfactant (SDS) by conductance measurement as well as absorption spectral analysis. DNA binding study was assessed through viscosity measurement and UV/Vis spectrophotometry. DPPH free radical scavenging assay was measured by UV/Vis spectrophotometry. The results showed nice biological potential of all the complexes.     

Tetra(μ3-hydroxo) bridged copper(II) tetranuclear cubane complexes: synthesis,crystal structure,and DNA binding studies

The tridentate Schiff base H₂L was synthesized by the condensation of equimolar amount of 1-amino-2-propanol and salicylaldehyde. The reaction of H₂L with an equimolar amount of Cu(CH₃COO)₂·H₂O in methanol leads to the formation of the tetranuclear Cu₄L₄, 1. However, reaction of equimolar amount of H₂L, copper(II) acetate, and 2,4,6-trimethylaniline in methanol forms a mixture of products which includes a discrete mononuclear complex Cu(L′)₂, 2m (where HL′ is a bidentate ligand), in addition to the tetranuclear Cu₄L₄ species, 2c. In both tetranuclear cubane species, the tridentate H₂L is both a chelating and a bridging ligand, after deprotonation of the enolic and the phenolic OH. The copper(II) centers are five-coordinate with a [N, O₄] donor set from the ligands. The coordination geometry about each copper is distorted square pyramidal with one nitrogen and two oxygen from one ligand and two oxygen from adjacent ligands in the next unit of the cubane. In mononuclear 2m, the ligand is bidentate and the coordination geometry around copper(II) is square planar. The absorption spectra strongly suggest that tetranuclear 1 interacts with CT-DNA.     

Synthesis and characterization of two acetato-bridged dinuclear copper(II) complexes with 4-bromo-2-((4 or 6-methylpyridin-2-ylimino)methyl)phenol as ligand

The synthesis and characterization of two new acetato-bridged dinuclear copper(II) complexes are described. Both compounds have the general formula [Cu(L)(µ-O₂C–CH₃)]₂, in which L = 4-bromo-2-((4-methylpyridin-2-ylimino)methyl)phenol or 4-bromo-2-((6-methylpyridin-2-ylimino)methyl)phenol. The title compounds consist of dinuclear units with bridging acetato groups and a ligand linked to each copper via the phenol oxygen and nitrogen. Both compounds were synthesized in a one-step reaction and characterized by elemental analysis, Fourier transform infrared (FTIR), electron spin resonance (ESR), and electronic spectra and by room temperature magnetic moments. The compounds exhibit antiferromagnetic interactions at room temperature. UV-Vis spectra show four absorptions attributed to d–d transitions of copper, ligand → metal charge transfer and π → π* or n → π* transitions of ligand. The FTIR spectra indicate a Cu₂O₄C₂ ring vibration. Both complexes show room temperature magnetic moments of about 1.6 B.M. per copper. The X-band ESR studies indicate a weak half-field band, characteristic of the Cu(II)–Cu(II) dimer, observed at 1552 and 1558 G for the complexes, strongly suggesting that the hyperfine structure arises from a spin triplet species. The spectra of frozen samples in DMSO or DMF at liquid nitrogen temperature show a typical Δm = 1 transition.     

Synthesis, spectroscopy, and magnetic characterization of copper(II) and cobalt(II) complexes with 2-amino-5-bromopyridine as ligand

The synthesis, spectroscopic, and magnetic characterization of two new copper(II) and cobalt(II) complexes are described. Both two compounds have the general formula [M(L)₂(Cl)₂] (M = Cu (I), Co (II); L = 2-amino-5-bromopyridine). These complexes were prepared in one-step synthesis and characterized by elemental analysis, FT-IR, UV-Vis, and EPR spectroscopy. Moreover, the single crystal structure of complex I was studied by the X-ray diffraction method. This compound consists of mononuclear units consisting of two ligands linked to metal via the nitrogen of pyridine ring. The UV-Vis spectra of copper(II) and cobalt(II) complexes show three and five absorption bands, respectively, attributed to the d-d transition of the metal ion, ligand → metal charge transfer and π → π* or n → π* transitions of the ligand. The FT-IR spectra show MN₂Cl₂ vibrations at 500–300 cm^?1. The complexes show room temperature magnetic moments of 1.78 and 4.12 μ_B for Cu(II) and Co(II), respectively. The X-band electron spin resonance (ESR) spectra of Cu(II) complex in DMF or DMSO frozen at liquid nitrogen temperature show the typical ΔM_S = ±1 transition.     

4-碘吡唑铜配合物的合成、结构及量子化学研究

分别采用水热反应法和溶液培养法, 合成了两个结构新颖的铜配合物[Cu₃(Ipz)₃] (Ipz=4-碘吡唑) (1), [Cu(SO₄)(Ipz)₄]·2H₂O·CH₃OH (2)。通过元素分析、红外光谱、紫外光谱和X-ray单晶衍射方法对其结构进行了表征。晶体结构表明, 配合物1属于正交晶系, Pnma空间群;配合物2属于三斜晶系, P1空间群。配合物1和2的中心金属铜原子的化合价分别是+1和+2价, 金属的配位环境以及配体的配位模式也完全不同。配合物1中金属铜为二配位, 与配体相互连接形成一个闭合的九元环结构;配合物2中金属铜为六配位, 通过配位的硫酸根分子连接形成一条无限的一维链状结构。此外, 对这2个配合物进行了量化计算, 同时还对配合物1进行了荧光光谱分析。     

A Tale of Biphenyl and Terphenyl Substituents for Structurally Diverse Ketiminato Magnesium,Calcium and Germanium Complexes

In this paper, we have used two N,O‐ketiminato ligands ( L1 and L2 ) with biphenyl and terphenyl substituent on the nitrogen atom. Deprotonation of L1 with KN(SiMe₃)₂ and subsequent reaction with MgI₂ led to a homoleptic dinuclear magnesium complex ( 1 ) with a Mg₂O₂ four‐membered ring. Deprotonation with nBuLi and subsequent reaction with MgI₂ afforded a unusual dinuclear magnesium complex ( 2 ) with a Mg₂O₂ ring. Extension of the ligand for calcium resulted in a trinuclear calcium complex ( 3 ) with six four‐membered Ca₂O₂ rings. We could not isolate any chelating complex when L2 was used as a ligand, and only oxygen bound magnesium ( 4 ) and calcium ( 5 ) adducts were isolated. DFT studies were performed to understand this dissimilar behavior. More diverse results were obtained when lithiated L1 and L2 were treated with germanium dichloride. We were able to stabilize a monomeric germylene monochloride ( 7 ) with L1 . However, with L2 , an unusual ligand scrambling, and a C?C coupling take place, leading to the formation of a secondary carbocation with GeCl₃‐ as a counter‐anion ( 8 ). Besides, a germanium dichloride adduct ( 9 ) bound to the oxygen center of the ligand was obtained as the minor product.     

Synthesis,characterization and in vitro biological activity of cobalt(II), copper(II) and zinc(II) Schiff base complexes derived from salicylaldehyde and D,L‐selenomethionine

New cobalt(II), copper(II) and zinc(II) complexes of Schiff base derived from D,L ‐selenomethionine and salicylaldehyde were synthesized and characterized by elemental analysis, IR, electronic spectra, conductance measurements, magnetic measurements and biological activity. The analytical data showed that the Schiff base ligand acts as tridentate towards divalent metal ions (cobalt, copper, zinc) via the azomethine‐N, carboxylate oxygen and phenolato oxygen by a stoichiometric reaction of M:L (1:1) to form metal complexes [ML(H₂O)], where L is the Schiff base ligand derived from D,L ‐selenomethionine and salicylaldehyde and M = Co(II), Cu(II) and Zn(II). ¹H NMR spectral data of the ligand and Zn(II) complex agree with proposed structures. The conductivity values between 12.87 and 15.63 S cm² mol^?1 in DMF imply the presence of non‐electrolyte species. Antibacterial and antifungal results indicate that the metal complexes are more active than the ligand. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis,Structure, Magnetic and Electrochemical Properties of a Dinuclear Copper Complex

A material for both magnetic coupling and electrocatalytic hydrogen evolution based on the copper complex, [(L)₂Cu₂] is formed by the reaction of CuCl₂ · 2H₂O with the tetradentate ligand 6‐(3‐aminomethylpropanol)‐2‐tert‐buty‐4‐methylphenol (H₂L), which is prepared by reaction of 2‐tert‐butyl‐4‐methylphenol, 3‐amino‐1‐propanol, and formaldehyde. Structural studies show that in the solid state complex 1 exhibits strong antiferromagnetic exchange interaction between copper(II) ions mediated by oxygen‐bridges. In liquid, 1 becomes a monomer, and can electrocatalyze hydrogen generation both from acetic acid with a turnover frequency (TOF) of 101.70 mol of hydrogen per mole of catalyst per hour at an overpotential (OP) of 941.6 mV (in DMF), and a natural buffer with a TOF of 650 mol of hydrogen per mole of catalyst per hour at an OP of 836.7 mV.     

Synthesis,structure and electrocatalytic properties of a water‐soluble copper complex supported by 2‐ethyl‐2‐(2‐hydroxybenzylideneamino)propane‐1,3‐diol ligand

The reaction of 2‐ethyl‐2‐(2‐hydroxybenzylideneamino)propane‐1,3‐diol (H₃L) with CuCl₂⋅2H₂O affords a new copper complex, [ClCu(H₂L)], which has been determined using X‐ray crystallography. In the solid, copper atom is four‐coordinated by two oxygen atoms and one nitrogen atom from the ligand and one chlorine atom. Electrochemical studies show that the complex can act as an electrocatalyst for hydrogen evolution from a dimethylformamide solution of acetic acid and a neutral buffer (pH = 7.0) with a turnover frequency of 46.2 and 482 moles of hydrogen per mole of catalyst per hour at an overpotential of 941.6 and 837.6 mV, respectively.     

Homo‐ and heteropolynuclear copper(II) complexes containing a new diimine–dioxime ligand and 1,10‐phenanthroline: synthesis,characterization, solvent‐extraction studies,catalase‐like functions and DNA cleavage abilities

A series of homo‐, heterodinuclear and homotrinuclear copper(II) complexes containing a new Schiff base ligand and 1,10‐phenanthroline were synthesized. Based on results of elemental analyses, FTIR, ¹H‐ and ¹³C‐NMR spectra, conductivity measurements and magnetic susceptibility measurements, the complexes had general compositions {[Cu(L)(H₂O)M(phen)₂](ClO₄)₂ [M = Cu(II), Mn(II), Co(II)]} and {[Cu₃(L)₂(H₂O)₂](ClO₄)₂}. The metal:L:phen ratio is 2:1:2 for the dinuclear copper(II) complexes and the metal:L ratio was 3:2 for the trinuclear copper(II) complex. The liquid–liquid extraction of various transition metal cations [Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Pb(II), Cd(II), Hg(II)] from the aqueous phase to the organic phase was carried out using the diimine–dioxime ligand. It was concluded that the ligand can effectively be used in solvent extraction of copper(II) from the aqueous phase to the organic phase. Furthermore, catalytic activitiy of the complexes for the disproportionation of hydrogen peroxide was also investigated in the presence of imidazole. Dinuclear copper(II)–manganese(II) complex has some similarity to manganese catalase in structure and activity. The interaction between these complexes and DNA has also been investigated by agarose gel electrophoresis; we found that the homo‐ and heterodinuclear copper complexes can cleave supercoiled pBR322 DNA to nicked and linear forms in the presence of H₂O₂. Copyright © 2009 John Wiley & Sons, Ltd.     

4-碘吡唑铜配合物的合成、结构及量子化学

分别采用水热反应法和溶液培养法,合成了两个结构新颖的铜配合物[Cu3(Ipz)3](Ipz=4-碘吡唑)(1),[Cu(SO4)(Ipz)4]·2H2O·CH3OH(2)。通过元素分析、红外光谱、紫外光谱和X-ray单晶衍射方法对其结构进行了表征。晶体结构表明,配合物1属于正交晶系,Pnma空间群;配合物2属于三斜晶系,P1空间群。配合物1和2的中心金属铜原子的化合价分别是+1和+2价,金属的配位环境以及配体的配位模式也完全不同。配合物1中金属铜为二配位,与配体相互连接形成一个闭合的九元环结构;配合物2中金属铜为六配位,通过配位的硫酸根分子连接形成一条无限的一维链状结构。此外,对这2个配合物进行了量化计算,同时还对配合物1进行了荧光光谱分析。     

Oxidation of bis(µ-halo)-bis[(diamine)copper(I)] complexes [LCuX]2; L = TMED, X = Cl, Br or I, L = TEED or TMPD, X = Cl, with the two electron organo oxidizing agent, tetrachloro-1,2-benzoquinone(TClBQ) in aprotic media: models for intermediates in catalytic catechol oxidase

Well structurally characterized bis(μ-halo)-bis[(diamine)copper(I)] complexes [LCuX]₂; L = TMED, tetramethylethylenediamine, X = Cl, Br or I and L = TEED, tetraethylethylenediamine, or TMPD, tetramethylpropane-diamine, X = Cl, react quantitatively with tetrachloro-1,2-benzoquinone (TClBQ) as two electron oxidizing agent in O₂-free CH₂Cl₂ or PhNO₂ to form a dimeric [LCuX]₂Cat (Cat = catechol) as indicated by cryoscopic measurements. Infrared spectra was in agreement with total reduction of TClBQ to the corresponding catechol. Electronic spectra indicated a dimeric distorted five coordinate Cu(II) and EPR spectra suggested a square pyramidal arrangement around the Cu(II) centers in [LCuX]₂Cat. The ligand field strength for diamine ligand was higher for the five member chelating ring (TMED) relative to the six membered one (TMPD). Electrochemical reduction of Cu centers in [LCuX]₂Cat were irreversible and occurred at a less negative potential when X = I.     

Synthesis, crystal structures, and properties of inorganic-organic hybrid complexes constructed from copper(II) macrocyclic fragment

Reaction of a macrocyclic copper(II) complex [Cu(L)](ClO₄)₂ · 3H₂O (I) (L = 1,3,10,12,16,19-hexaazatetracyclotetracosane) with a hexapod carboxylate ligand H₆TTHA (H₆TTHA = 1,3,5-triazine-2,4,6-triamine hexaacetic acid) and a tripod carboxylate ligand H₃TATB (H₃TATB = 4,4′,4″-S-triazine-2,4,6-triyl-tribenzoic acid) yielded two mononuclear copper(II) complexes [Cu(L)][H₄TTHA] · 4H₂O (II) and [Cu(L)][HTATB] · 4H₂O (III). The complexes I–III have been structurally characterized. The crystal structures of complexes II and III show the copper(II) ion has a distorted pentacoordinate square-pyramidal geometry with two secondary and two tertiary amines from the macrocyclic complex [Cu(L)]²⁺ and one oxygen atom from the carboxylate ligand group at the axial position. The UV-Vis spectra are utilized to discuss the hydrolysis of the complex II.     

Cobalt (II) and Copper (I) Complexes of Rigid Bidentate [N‐(2, 6‐Diisopropyl‐phenyl)imino]acenapthenone Ligand: Synthesis and Structural Studies

The cobalt(II) complex [CoCl₂(2, 6‐iPrC₆H₃‐BIAO)]₂ ( 1 ) of rigid unsymmetrical imine, carbonyl mixed ligand [N‐(2, 6‐diisopropylphenyl)‐imino]acenapthenone] (2, 6‐iPrC₆H₃‐BIAO) ( L1 ) can be achieved by the reaction of CoCl₂ and neutral [N‐(2, 6‐diisopropylphenyl)‐imino]acenapthenone] ligand. When ligand L1 reacted with CuCl in dichloromethane solution, only nitrogen coordinated copper complex [CuCl(2, 6‐iPrC₆H₃‐BIAO)] ( 2 ) was obtained. In the solid‐state structure, compound 1 is dimeric through the chelating two μ₂ chlorine atoms and each cobalt atom adopts either a distorted trigonal bipyramidal or a distorted square pyramidal arrangement. In contrast, the molecular structure of compound 2 reveals that copper is coordinated by imino nitrogen and adopts a linear arrangement around the central metal atom. The crystal structure of the rigid bidentate mixed nitrogen and oxygen ligand (2, 6‐iPrC₆H₃‐BIAO) ( L1 ) is also reported.     

Synthesis,spectral, and biological studies of transition metal chelates of N-[1-(3-aminopropyl)imidazole]salicylaldimine

Tridentate chelate complexes M[LX?·?2H₂O], where M?=?Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) have been synthesized from the Schiff base L?=?N-[1-(3-aminopropyl)imidazole]salicylaldimine and X?=?Cl. Microanalytical data, UV-Vis, magnetic susceptibility, IR, ¹H-NMR, mass, and EPR techniques were used to confirm the structures. Electronic absorption spectra and magnetic susceptibility measurements suggest square-planar geometry for copper complex and octahedral for other metal complexes. EPR spectra of copper(II) complex recorded at 300?K confirm the distorted square-planar geometry of the copper(II) complex. Biological activities of the ligand and metal complexes have been studied on Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans by the well diffusion method. The activity data show the metal complexes to be more potent than the parent ligand against two bacterial species and one fungus. The electrochemical behavior of the copper complex was studied by cyclic voltammetry.     

A new bis(azine) tetradentate ligand and its transition metal complexes: Synthesis,characterisation, and extraction properties

A new bis(bidentate) azine ligand was prepared by linking (1Z,1′Z)-1,1′-{butane-1,4-diylbis[oxybenzene-4,1-diyl(1Z)ethyl-1-ylidene]}dihydrazine to salicylaldehyde. Two kinds of binuclear copper(II) and nickel(II) complexes with different stoichiometries were prepared. Reaction of bis(azine) ligand with Cu(II) and Ni(II) acetate at a 1: 1 mole ratio gave double-stranded binuclear bis(azine) complexes with stoichiometry [M(L)(H₂O)₂]₂ containing [M(II)N₂O₂] centres while at a 2: 1 mole ratio, reaction of Cu(II) and Ni(II) chloride with bis(azine) resulted in dinuclear metal complexes with the general stoichiometry [M₂(L)Cl₂(H₂O)₂]. Structures of the bis(azine) ligand and its complexes were identified by elemental analysis, IR and UV-VIS spectra, magnetic susceptibility measurements, TGA, and powder XRD. Extraction properties of the bis(azine) ligand towards some transition metal cations and dichromate anions were also reported. It was found that the bis(azine) ligand does not extract cations but it has high extraction ability towards dichromate anions.     

Synthesis, spectral characterization, and structural investigation of mononuclear salen-type Cu(II) and Zn(II) complexes of a potentially octadentate N2O6 Schiff base ligand derived from binaphthol

A new potentially octadentate N₂O₆ Schiff base ligand, H₂L derived from the condensation of 2,2′-(1,1′-binaphthyl-2,2′-diylbis(oxy))dianiline and o-vanillin, along with its copper(II) and zinc(II) complexes, is synthesized and has been characterized by elemental analyses, IR, UV–vis, ¹H and ¹³C NMR spectra, as well as conductivity measurements. H₂L forms mononuclear complexes of 1:1 (metal:ligand) stoichiometry with Cu(II) and Zn(II), and conductivity data confirm the non-electrolyte nature of these complexes. The [ZnL] and [CuL] complexes display very different solid-state structures, as determined by X-ray crystallography. While the [ZnL] complex has a distorted octahedral geometry about the metal, the [CuL] complex displays a distorted square planar geometry about the copper, with long Cu–O(ether) distances of 2.667 Å.     

Complex of copper(II) with phenoxo and hexamethylphosphoramide ligands and its decomposition

The 2,4,6-trichlorophenoxo–hexamethylphosphoramide(HMPA)–copper(II) complex was isolated by the reaction of copper(II) chloride with 2,4,6-trichlorophenol, sodium methoxide, and HMPA in methanol solvent under an atmosphere of nitrogen. This complex has the composition of Cu·HMPA·2(C₆H₂Cl₃O). The molecular weight determination was consistent with the copper(II) complex of binuclear structure. The infrared, electronic, and ESR spectra and magnetic susceptibility of the copper(II) complex are discussed in relation to its structure. Decomposition of the copper(II) complex in refluxing benzene yielded poly(dichlorophenylene oxide), coupling product of the 2,4,6-trichlorophenoxo ligand of the copper(II) complex. Electron spin resonance (ESR) measurements on the copper(II) complex in the solid state in a degassed sealed tube at 120 ± 5°C indicated that the phenoxy radical was generated during the period of decomposition and the intensity of the ESR spectra based on copper(II) ion decreased with the measurement time. From these ESR spectra, a possible initial step involving one electron transfer of the decomposition of the 2,4,6-trichlorophenoxo–HNPA–copper(II) complex is discussed.     

Synthesis,Crystal Structure,DNA‐binding Properties and Antioxidant Activity of a Copper(II) Complex with Naphthalimide Schiff Base

The Schiff N‐allylamine‐4‐(ethylenediamine‐5‐methylsalicylidene)‐1,8‐naphthalimide (H₂L) and its copper(II) complex, [Cu(HL)₂] · 0.5DMF, were synthesized and characterized. The crystal structure of the Cu^II complex reveals a slightly distorted square‐planar arrangement provided by two N and O donors from two deprotonated ligands. In addition, the DNA‐binding properties of the ligand and Cu^II complex were investigated by fluorescence spectra, electronic absorption, and viscosity measurements. The experimental studies of the DNA‐binding properties indicated that the ligand and Cu^II complex reacted with DNA via intercalation binding mode, and binding affinity for DNA takes the order: ligand > Cu^II complex. The antioxidant assay in vitro suggested that both exhibited potential intensely antioxidant properties, and the ligand is more effective than its Cu^II complex.     

Copper(II) complex based on a V-shaped ligand, 2,6- bis (2-benzimidazolyl)pyridine: synthesis,crystal structure,DNA-binding properties,and antioxidant activities

A copper(II) complex based on a V-shaped ligand, 2,6-bis(2-benzimidazolyl)pyridine (bbp), has been synthesized and characterized by elemental analysis, molecular conductivity, ¹H NMR, IR, UV-Vis spectra, and X-ray single-crystal diffraction. The crystal structure of [Cu(bbp)₂](pic)₂?·?2DMF (pic?=?picrate) shows copper is six-coordinate forming a distorted octahedron. The interaction between Cu(II) complex and DNA was investigated by spectrophotometric methods and viscosity measurement. The experimental results suggest that the Cu(II) complex binds to DNA via intercalation. Antioxidant assay in vitro also shows that the Cu(II) complex possesses significant antioxidant activities.