A novel copper(II) complex constructed with mixed ligands of biphenyl-4,4′-dicarboxylic acid (H2bpdc) and dipyrido[3,2-d:2′,3′-f]quinoxaline (Dpq): Synthesis,structure, electrochemistry and electrocatalysis

A novel metal–organic framework [Cu₂(bpdc)₂(Dpq)₂(H₂O)]·H₂O (1) has been obtained from hydrothermal reaction of copper chloride with the mixed ligands [biphenyl-4,4′-dicarboxylic acid (H₂bpdc) and dipyrido[3,2-d:2′,3′-f]quinoxaline (Dpq)], and structurally characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction analysis. The unique feature is that there simultaneously exist two kinds of one-dimensional (1-D) zigzag polymeric chains in complex 1. Moreover, the 1-D polymeric chains are ultimately packed into a three-dimensional (3-D) supramolecular framework through two different hydrogen bonding interactions. The adjacent different chains are linked by C–H?O hydrogen bonding interactions, and the same kind chains are further connected through C–H?π stacking interactions. Additionally, the complex 1 was used as solid bulk-modifier to fabricate renewable carbon paste electrode (Cu-CPE) by the direct mixing method. The electrochemical behavior and electrocatalysis of Cu-CPE have been studied in detail. The results indicate that Cu-CPE give one-electron quasi-reversible redox waves in potential range of 400 to ?300 mV due to the metal copper ion Cu(II)/Cu(I). The Cu-CPE showed good electrocatalytic activity toward the reduction of the bromate, nitrite and hydrogen peroxide. The electrocatalytic reduction peak currents of KBrO₃, KNO₂ and H₂O₂ showed a linear dependence on their concentrations. All of the results revealed that the Cu-CPE had a good reproducibility, remarkable long-term stability and especially good surface renewability by simple mechanical polishing in the event of surface fouling, which is important for practical application.     

Synthesis, structures, electrochemistry and electrocatalysis of two novel copper(II) complexes constructed with aromatic polycarboxylates and dipyrido[3,2-d:2′,3′-f]quinoxaline

Two novel coordination polymers [Cu₃(1,3-BDC)₄(Dpq)₂] (1) and [Cu₂(BTC)(OH)(Dpq)₂] · H₂O (2), have been hydrothermally synthesized by self-assembly of aromatic polycarboxylate ligands 1,3-H₂BDC (1,3-H₂BDC = 1,3-benzenedicarboxylate) or H₃BTC (H₃BTC = 1,3,5-benzenetricarboxylate), chelating ligand Dpq (Dpq = dipyrido[3,2-d:2′,3′-f]quinoxaline), and copper chloride. X-ray diffraction analysis reveals that each trinuclear Cu^II cluster is bridged by two coordination modes of 1,3-BDC ligands to form one-dimensional (1-D) chain structure in complex 1. Complex 2 possesses a two-dimensional (2-D) layer network composed of dinuclear [Cu₂(OH)(Dpq)₂] unit and bridging ligand BTC. The adjacent chains for 1 or the adjacent layers for 2 are further linked by π-π stacking interactions to form the three-dimensional (3-D) supramolecular frameworks. Moreover, the electrochemical properties of the two copper(II) complexes bulk-modified carbon paste electrodes (Cu-CPEs: 1-CPE and 2-CPE) have been studied, and the results indicate that both Cu-CPEs give one-electron quasi-reversible redox waves in potential range of 600 to −400 mV due to the metal copper ion Cu(II)/Cu(I). The Cu-CPEs have good electrocatalytic activities toward the reduction of nitrite and bromate in 0.1 M pH 2 phosphates buffer solution, and have remarkable long term stability and especially good surface renewability by simple mechanical polishing in the event of surface fouling, which is important for practical application.     

Synthesis,Crystal Structure and DNA Cleavage Activity of a Ternary Copper(Ⅱ)Complex of Dipyrido[3,2-d:2',3'-f]-quinoxaline and Glycine

A ternary copper(II) complex, [Cu(Dpq)(Gly)(H₂O)]·NO₃·1.5H₂O (Dpq=dipyrido[3,2‐d:2′,3′‐f]quinoxaline, Gly=glycine), has been synthesized and structurally characterized. The complex crystallized in a triclinic system with space group P‐1, a=6.6979(9) Å, b=7.6351(10) Å, c=18.980(2) Å, α=85.815(2) °, β=88.182(2) °, γ=71.203(2) °. The five‐coordinate copper(II) center is a distorted square pyramid. Absorption spectra, fluorescence spectra and CD spectra showed that there were interactions between the copper complex and DNA through a groove binding mode. The complex exhibited efficient DNA cleavage activity at micromolar concentration in the presence of ascorbate with hydroxyl radicals as the active species.     

Self-assembled multilayer films of poor water-soluble copper(II) complexes constructed from dipyrido[3,2-d:2′,3′-f]quinoxaline (Dpq) ligand as well as their fluorescent properties

New multilayer films were prepared by alternating adsorption of poly(sodium 4-styrenesulfonate) (PSS) and a new complex of [Cu₂(Dpq)₂(Ac)₂(H₂O)₂] (ClO₄)₂·H₂O (1) (Dpq=dipyrido[3,2-d:2′,3′-f]quinoxaline, Ac=acetate) or a related complex [Cu(Dpq)₂(H₂O)] (ClO₄)₂·H₂O (1a) by electrostatic layer-by-layer self-assembly technique, respectively. Compounds 1 and 1a have been synthesized and structurally characterized by elemental analyses, IR spectroscopy, and single-crystal X-ray diffraction analyses. Single-crystal X-ray analyses show that complexes 1 and 1a possess a dinuclear and a mononuclear structure, respectively, which are further extended into layered frameworks by π-π stacking and hydrogen-bonding interactions. The multilayer films were characterized by UV-vis spectroscopy, fluorescence spectroscopy, small-angle X-ray reflectivity measurements, and atomic force microscopy (AFM) imaging. UV spectroscopy shows that the deposition process is regular and highly reproducible from layer to layer. AFM image indicates that the film surface is uniform and smooth. The fluorescent properties of the films were studied and the results showed that the forming condition of the films had great influence on their properties.     

Binary and Ternary Metal Complexes Derived from Cu Acetate with Some Sulfur-Containing Chemotherapeutic Agents

Two ternary complexes, [Cu₂(Pir)(Pen)(OH)(Ac)H₂O] and [Cu(Pir)(Cap)(Ac)] ½H₂O (where, Pen = D-penicillamine, Cap = captopril, and Pir = piroxicam) have been synthesized and characterized using elemental analyses, spectroscopic analyses (IR, UV-vis, MS), thermal analyses (TGA), conductance measurements, and magnetic measurements. The binary complexes, [Cu₂(Pen)(OH)₂(H₂O)₂] 4H₂O and [Cu(Cap)Ac] 3/2H₂O, have also been prepared and characterized by these techniques to facilitate the interpretation of the mixed ligand complexes. The results show that D-penicillamine can coordinate two copper atoms through amino nitrogen, and thiol sulfur after displacement of a hydrogen atom. At the same time, the ligand coordinates to the second copper atom through a carboxyl group after displacement of a hydrogen from the latter group. Captopril coordinates through thiol sulfur and carbonyl oxygen. Piroxicam coordinates as a neutral bidentate ligand in the keto form through carbonyl oxygen and pyridyl nitrogen. The magnetic moment measurements of complexes containing captopril indicate the reduction of Cu(II) to Cu(I) by the thiol group.     

A fluorophore‐labelled copper complex: crystal structure,hybrid cyclic water–perchlorate cluster and biological properties

A fluorophore‐labelled copper(II) complex, aquabis(dimethylformamide‐κO )(perchlorato‐κO )[2‐(quinolin‐2‐yl)‐1,3‐oxazolo[4,5‐f ][1,10]phenanthroline]copper(II) perchlorate monohydrate, [Cu(ClO₄)(C₂₂H₁₂N₄O)(C₃H₇NO)₂(H₂O)]ClO₄·H₂O, has been synthesized and characterized. A cyclic hydrogen‐bonded water–perchlorate anionic cluster, i.e. [(ClO₄)₂(H₂O)₂]²⁻, has been identified within the structure. Each cyclic anionic cluster unit is interconnected by hydrogen bonding to the cation. The cations join into an infinite hydrogen‐bonded chain running in the [010] direction. Furthermore, interaction of the complex with calf‐thymus DNA (CT‐DNA) and cellular localization within the cells was explored. Spectroscopic studies indicate that the compound has a good affinity for DNA and stains the nucleus of the cells.     

A new POM-templated metal–organic complex based on the flexible bis-pyridyl-bis-amide ligand

A new POM-templated metal?Corganic complex [Cu₄(L)₇(H₂O)₁₂(SiMo₁₂O₄₀)₂]·7H₂O [L?=?N,N??-bis(3-pyridinecarboxamide)-1,6-hexane], has been hydrothermally synthesized and characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction analysis. The results reveal that the complex is a 2D metal?Corganic coordination framework of [Cu₄(L)₇(H₂O)₁₂] _n ⁸ⁿ⁺ cations containing decanuclear cycles with dimensions of ca. 17.55?×?57.42 ?, in which the SiMo₁₂O₄₀ ^4? anions act as non-coordinated anionic templates. The electrochemical properties of a bulk-modified carbon paste electrode of the complex have been investigated, and the results indicate that the complex-modified CPE has good electrocatalytic activity toward the reduction of nitrite in aqueous 1?M H₂SO₄ solution.     

基于二-吡嗪-(2, 3-f: 2′3′-h)-喹喔啉和吡啶-2，5-二羧酸混合配体的两个新奇金属有机超分子骨架的水热合成、晶体结构与光致发光

以二-吡嗪-(2, 3-f: 2′3′-h)-喹喔啉(Dpq)和吡啶-2,5-二羧酸(2,5-H2pda)两种混合配体与不同金属硝酸盐为原料,通过水热反应得到了两个新奇的金属有机骨架[Zn2(Dpq)2(2,5-pda)2(H2O)2]·2H2O(1)和[Cd2(Dpq)2(2,5-pda)2]·2H2O(2),并经元素分析、TG、IR、X-射线单晶衍射分析进行了表征。结构分析表明,2,5-pda采取不同的配位方式桥连金属离子分别形成了二聚物1和2D菱形网络2。在化合物1中,相邻的二聚物通过氢键和π-π堆积作用形成扭曲的a-Po超分子结构。在化合物2中,相邻的配位聚合物层通过氢键拓展成扭曲的a-Po超分子骨架,而π-π堆积起到巩固骨架的作用。化合物1和2的结构差异表明了金属离子和配体在配位聚合物自组装过程中对结构的影响。此外固态标题化合物在室温下表现出蓝色的发光性质。     

Tracking the dissolution–recrystallization structural transformation (DRST) of copper(II) complexes: a combined crystallographic,mass spectrometric and DFT study

Methanol‐ and temperature‐induced dissolution–recrystallization structural transformation (DRST) was observed among two novel Cu^II complexes. This is first time that the combination of X‐ray crystallography, mass spectrometry and density functional theory (DFT) theoretical calculations has been used to describe the fragmentation and recombination of a mononuclear Cu^II complex at 60 °C in methanol to obtain a binuclear copper(II) complex. Combining time‐dependent high‐resolution electrospray mass spectrometry, we propose a possible mechanism for the conversion of bis(8‐methoxyquinoline‐κ²N,O)bis(thiocyanato‐κN)copper(II), [Cu(NCS)₂(C₁₀H₉NO)₂], Cu1 , to di‐μ‐methanolato‐κ⁴O:O‐bis[(8‐methoxyquinoline‐κ²N,O)(thiocyanato‐κN)copper(II)], [Cu₂(CH₃O)₂(NCS)₂(C₁₀H₉NO)₂], Cu2 , viz. [Cu(SCN)₂( L )₂] ( Cu1 ) → [Cu( L )₂] → [Cu( L )]/ L → [Cu₂(CH₃O)₂(NCS)₂( L )₂] ( Cu2 ). We screened the antitumour activities of L (8‐methoxyquinoline), Cu1 and Cu2 and found that the antiproliferative effect of Cu2 on some tumour cells was much greater than that of L and Cu1 .     

Synthesis, Structure and Characterization of Two-dimensional Network Copper Complex [Cu_3(nta)_2(azpy)_2(H_2O)_2]·6H_2O

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Inorganic‐organic Microporous Solid of Wells‐Dawson Type Polyoxometalate: Synthesis,Characterization, and Electrochemical Properties

An inorganic‐organic hybrid solid (H_6/5bppy)₅[P₂W₁₈O₆₂]·4.5H₂O ( 1 ) (bppy = 4‐(5‐(4‐bromophenyl)pyridin‐2‐yl)pyridine) was hydrothermally synthesized by using pre‐constructed Wells‐Dawson type salt α‐K₆P₂W₁₈O₆₂·15H₂O as inorganic moiety. The crystal structure keeps integrated and steady under the interactions together of aryl packing, hydrogen bonding and halogen bonding. X‐ray single crystal structure analysis reveals that compound 1 contains cavities with the sizes of about 6 × 8Å, in which H₂O molecules are captured. The hybrid was used as a solid bulk modifier to fabricate a three‐dimensional bulk‐modified carbon paste electrode ( 1 ‐CPE) by direct mixing. The electrochemical and electrocatalytic behavior of the 1 ‐CPE has been studied in detail. The results exhibit that the redox ability of the Wells‐Dawson polyanions can be maintained in the hybrid solid, which has a good electrocatalytic activity toward the reduction of bromate and hydrogen peroxide. A hydrodynamic voltammetric experiment was performed to characterize the electrode as an amperometric sensor for the determination of hydrogen peroxide. The 1 ‐CPE showed long‐term stability and excellent reproducibility of surface renewal.     

Di‐μ‐hydroxo‐bis­[aqua(1,10‐phenanthroline‐κ2N,N′)copper(II)] trans‐bis(2‐{[(E)‐5‐formyl‐2‐oxido‐κO‐benzyl­idene]­amino‐κN}ethanesulfonato(2–))copper(II) hexahydrate

The title compound, [Cu₂(OH)₂(C₁₂H₈N₂)₂(H₂O)₂][Cu(C₁₀H₉NO₅S)₂]·6H₂O, is comprised of a copper‐centred complex cation and a copper‐centred complex anion; the cation lies about an inversion centre and in the anion the Cu atom lies on an inversion centre. In the doubly charged bridged dicopper cation, each Cu centre has distorted square‐pyramidal geometry. In the square‐planar dianion, two sulfonate ligands are trans coordinated to the Cu atom via a deprotonated hydroxyl O atom and an imine N atom, forming two six‐membered chelate rings. The structure is stabilized by an extensive hydrogen‐bond system and aromatic‐ring stacking interactions.     

A novel inorganic–organic hybrid compound constructed from copper(II)-monosubstituted polyoxometalates and poly(amidoamine)

A novel inorganic–organic hybrid compound constructed from copper(II)-monosubstituted polyoxometalate Na₅PW₁₁Cu(H₂O)O₃₉ (PW₁₁Cu) and poly(amidoamine) (PAMAM) dendrimer was prepared at room temperature in an aqueous solution. The title compound PW₁₁Cu/PAMAM was characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction, indicating that the PW₁₁Cu was chemically anchored to PAMAM. The compound was first used as a bulk-modifier to fabricate a chemically modified carbon paste electrode (CPE) by direct mixing. The PW₁₁Cu/PAMAM bulk-modified CPE showed well-defined cyclic voltammograms with four redox couples in 0.2 M NaAc buffer solution and high electrocatalytic activity for the reduction of hydrogen peroxide and nitrite. Furthermore, the CPE revealed good stability due to the insolubility of the title compound and the interaction between PW₁₁Cu and PAMAM.     

Preparation,Structure, Spectral,and Magnetic Properties of Copper(II) Halogenonicotinates: Crystal and Molecular Structure of Tetrakis(μ‐2‐chloronicotinato‐O,O′)‐diaquadicopper(II)

The characterization of the complexes [Cu₂(2‐Clnic)₄(H₂O)₂] ( 1 ), [Cu(2,6‐Cl₂nic)₂(H₂O)₂] ( 2 ) and [Cu(5‐Brnic)₂(H₂O)₂]_n ( 3 ) (where 2‐Clnic = 2‐chloronicotinate, 2,6‐Cl₂nic = 2,6‐dichloronicotinate or 5‐Brnic = 5‐bromonicotinate) was based on elemental analysis, IR, electronic and EPR spectra, and magnetic susceptibility. Complex 1 was also studied by X‐ray analysis at 298 1a and 80 K 1b . The complex 1 contains a dinuclear Cu‐acetate molecular structure in which the carboxyl groups of the 2‐chloronicotinate ligands act as bridges and water molecules are at apical positions. The stereochemistry about Cu atom at both temperatures is typical for square pyramidal geometry with CuO₄O chromophore. The Cu‐Cu distance is 2.6513(8) and 2.6382(6) Å for 1a and 1b , respectively. The Cu atoms are displaced by 0.2069(9) and 0.1973(7) Å, respectively, from the plane containing four oxygen atoms bonded to the Cu atom toward the apical water molecules. Strong and weak hydrogen bonds as well as C–Cl···π interactions in the crystal structure are discussed as well. Both complexes, monomeric [Cu(2,6‐Cl₂nic)₂(H₂O)₂] ( 2 ) and polymeric [Cu(5‐Brnic)₂(H₂O)₂]_n ( 3 ), possess octahedral copper(II) stereochemistry with differing tetragonal distortions.     

Nucleic Acid Biosensor for Detection of Human Immunodeficiency Virus Using Aquabis(1,10‐phenanthroline)copper(II) Perchlorate as Electrochemical Indicator

The electrochemical behavior of aquabis(1,10‐phenanthroline)copper(II) perchlorate [Cu(H₂O)(phen)₂]·2ClO₄, where phen=1,10‐phenanthroline, on binding to DNA at a glassy carbon electrode (GCE) and in solution, was described. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) results showed that [Cu(H₂O)(phen)₂]²⁺ had excellent electrochemical activity on the GCE with a couple of quasi‐reversible redox peaks. The interaction mode between [Cu(H₂O)(phen)₂]²⁺ and double‐strand DNA (dsDNA) was identified to be intercalative binding. An electrochemical DNA biosensor was developed with covalent immobilization of human immunodeficiency virus (HIV) probe for single‐strand DNA (ssDNA) on the modified GCE. Numerous factors affecting the probe immobilization, target hybridization, and indicator binding reactions were optimized to maximize the sensitivity and speed of the assay. With this approach, a sequence of the HIV could be quantified over the range from 7.8×10^?9 to 3.1×10^?7 mol·L^?1 with a linear correlation of γ=0.9987 and a detection limit of 1.3×10^?9 mol·L^?1.     

trans‐Di­aqua­bis(N‐acetyl­anthranilato‐O,O′)copper(II)

The title monomeric copper(II) complex, [Cu(C₉H₈NO₃)₂(H₂O)₂], (I), shows a square‐planar coordination and has an inversion centre at the Cu atom. The carboxyl­ate group of the N‐acetyl­anthranilate ion acts as a monodentate donor ligand to copper and as an acceptor of an intramolecular O—H?O hydrogen bond from the coordinated water mol­ecule, with an O?O distance of 2.581 (2) Å.     

A New Mixed‐Valent Copper Cyanido Complex and a New Copper(II) Acetato Complex,Prepared with an Ionic Liquid

When copper(II) acetate is treated with the ionic liquid n‐butylmethylimidazolium cyanide (BMIm‐CN), in ethanol solution, two new copper coordination compounds are obtained. (BMIm)₂[Cu₄(CN)₇] comprises a 3D coordination polymer of cyanide bridged copper ions. This anionic coordination polymer contains Cu^I as well as Cu^II ions, i.e. it is a mixed‐valent compound. The polymer can be described as honeycomb structure with the BMIm⁺ cation being located in the cages. The second compound obtained from the chemical reaction is (BMIm)[Cu₂(OAc)₅][Cu(OAc)₂(H₂O)]₂ · C₂H₅OH, which can be described as double‐salt. The first unit (BMIm)[Cu₂(OAc)₅] contains paddle wheel copper(II) acetato moieties, which are bridged by additional acetato ligands and form infinite chains. The second part of the double salt is the neutral, [Cu(OAc)₂(H₂O)]₂ complex. These two parts as well as the co‐crystallized ethanol molecule are connected through a network of hydrogen bridges.     

(−)‐Sparteine copper(II) diacetate

The chiral nitrogen‐chelating alkaloid (?)‐sparteine acts as a bidentate ligand, reacting with copper(II) acetate in ethanol to form the title complex, [Cu(CH₃COO)₂(C₁₅H₂₆N₂)], with the two acetate groups occupying the remaining coordination sites in a monodentate fashion to produce a distorted four‐coordinate tetrahedral structure. The dihedral angle between the N—Cu—N and O—Cu—O planes is 45.8 (3)°.     

Two Novel 3D Copper Phthalate Coordination Complexes Incorporating Isomeric Flexible Bis(pyridylformyl)piperazine Ligands

Two novel metal‐organic coordination complexes [Cu(3‐bpfp)(pht)(H₂O)] · 2H₂O ( 1 ) and [Cu₃(4‐bpfp)(pht)₂(OH)₂] · 2H₂O ( 2 ) were hydrothermally synthesized by self‐assembly of phthalic acid (H₂pht), flexible bis(pyridylformyl)piperazine ligands [3‐bpfp = bis(3‐pyridylformyl)piperazine, 4‐bpfp = bis(4‐pyridylformyl)piperazine], and copper chloride. Single crystal X‐ray diffraction analysis revealed that the adjacent Cu^II ions are connected by pht showing different coordination modes [a bis(monodentate) coordination mode for 1 and a monodentate‐bidentate coordination mode for 2 ] to form 1D Cu‐pht‐Cu chains in 1 and 2D Cu‐pht layers in 2 . In compound 1 , a twofold interpenetrated CdSO₄‐like topology is formed by connection of 3‐bpfp. Using the isomeric ligand 4‐bpfp instead of 3‐bpfp resulted in the formation of 2 , which displays a novel 3, 4, 4, 4‐connected tetranodal 3D coordination polymeric framework. The ligand 3‐bpfp adopts a μ₂‐bridging coordination mode in 1 (by ligation of the pyridyl nitrogen atoms), whereas the ligand 4‐bpfp adopts a μ₄‐bridging coordination mode (by ligation of pyridyl nitrogen and carbonyl oxygen atoms) in 2 . Moreover, the electrochemical properties of carbon paste electrodes bulk modified with the two copper complexes were studied.     

Synthesis and magnetism of 6-nitrobenzimidazolate and imidazolate-bridged copper(II) complexes

Summary Four new trinuclear copper(II) complexes, [Cu(phen)-(NBzIm)] (ClO₄) (1), [Cu(bpy)(NBzIm)](ClO₄) (2), [Cu-(Me₂-bpy)(NBzIm)](Ac)·1/2H₂O (3) and [Cu(Me₂-bpy)-(Im)](ClO₄)·1/2H₂O (4) (phen = 1, 10-phenanthroline, bpy = 2,2-bipyridine, NBzIm = 6-nitrobenzimidazolate ion, Im=imidazolate ion) have been prepared and characterized by variable temperature magnetic susceptibility measurements. A weak antiferromagnetic spin exchange interaction operates between copper(II) ions, exchange integrals evaluated as J =-23.82 cm^-1 for (1); and J=-21.91 cm^-1 for (2).