Effect of atmosphericwater vapor on the kinetics of thermal decomposition of copper(II) carbonate hydroxide

The effect of atmospheric water vapor on the kinetic rate behavior of the thermal decomposition of copper(II) carbonate hydroxide, Cu₂CO₃(OH)₂, was investigated by means of TG-DTA coupled with a programmable humidity controller. With increasing water vapor pressure p(H₂O) from 0.8 to 10.6 kPa, a systematic reduction of the reaction temperature of the thermal decomposition was observed as the continuous trend from the previous works at the lower p(H₂O). Through a comparative kinetic analysis of the reaction at different p(H₂O), a catalytic action of the atmospheric water vapor on the nucleation process at the first half of the reaction was identified as the possible origin of the reduction of the reaction temperature.     

Synthesis and characterisation of phenoxo bridged dinuclear complexes of copper(II)

A series of model complexes for the type III site, in oxidised hemocyanin, containing Cu₂(μ-0Ph)³⁺ core have been synthesised using a heptadentate ligand (H₃L) formed from the Schiff base condensation of triethylenetetramine and salicylaldehyde. The ligand provides one imine and one inbuilt imidazole nitrogen and two phenolic oxygen donors with both five- and six-membered chelate rings to each metal centre. In the pentacoordinated complexes [Cu₂(L)X]·nH₂O, a third exogenous bridging ligand is present. The TG curve indicates the loss of lattice water molecules between 70 and 125°C. The residue after decomposition is CuO above 550°C. Theg values of theX-band EPR spectrum of [Cu₂L(μ-OAc)]·2H₂O in methanol glass (77 K) are typical of a variety of bridged copper(II) dimers. The copper-copper magnetic interaction is dependent on the presence and nature of X in these complexes.     

Synthesis,structures and magnetic properties of a series of polynuclear copper(II)‐lanthanide( III) complexes assembled with carboxylate and hydroxide ligands

Heterometallic copper(II)‐lanthanide(III) complexes have been made with a variety of exclusively O‐donor ligands including betaines (zwitterionic carboxylates) and chloroacetate, which are dinuclear CuLn, tetranuclear Cu₂Ln₂, pentanuclear C_u3Ln₂, and octadecanuclear C_u12 complexes. The results show that subtle changes in both the carboxylates and acidity of the reaction solution can cause drastic changes in the structures of the products. Magnetic studies exhibit that shielding of the Ln³⁺ 4f electrons by the outer shell electrons is very effective to preclude significant coupling interaction between the Ln³⁺ 4f electrons and Cu²⁺ 3d electrons in either a mono‐atomic hydroxide‐bridged, or a carboxylate‐bridged system.     

Synthesis and X-ray structural characterization of cobalt(II), copper(II), and silver(I) complexes of triphenylphosphoniopropionate

Four transition-metal carboxylate-like complexes have been synthesized from the reaction of the tertiary phosphine betaine triphenylphosphoniopropionate, Ph₃P⁺(CH₂)₂CO ₂ ^– , with Co(ClO₄)₂· 6H₂O, Cu(ClO₄)₂·6H₂O, Cu(BF₄)₂·xH₂O, and AgClO₄, respectively, and fully characterized by single-crystal X-ray analysis. [CoPh₃P(CH₂)₂CO_{2 4}(H₂O)₂](ClO₄)₂·2H₂O, 1, space groupP¯ l witha=9.195(2),b=13.000(2),c=18.795(3) Å,=102.52(1),=90.12(1),=109.28(2)° andZ=1; [CuPh₃P(CH₂)₂CO_{2 4}][Cu₂ -Ph₃P(CH₂)₂CO₂ -O,O ₄(H₂O)₂] (ClO₄)₆· 4H₂O, 2, space groupP2_l/c witha=14.225(3),b=24.624(6),c=24.297(5) Å,=94.18(1)°, andZ=2; [CuPh₃,P(CH₂)₂CO₂Me₂N(CH₂)₂NMe₂(H₂O)₂](BF₄)₂,3, space groupP2_l/c witha=17.668(2),b=13.454(3),c=15.876(2) Å,=116.45(1)°, andZ=4; [Ag₂Ph₃P(CH₂)₂CO_{2 2}(ClO₄)]₂(ClO₄)₂,4, space groupP¯ l witha=10.925(2),b=13.110(3),c=18.795(3) Å,=82.93(3),=87.45(3),=67.49(3)°, andZ=2. In complex1, the cobalt(II) atom is located in an inversion center and coordinated by four unidentate betaine ligands and a pair oftrans aqua ligands, and strong hydrogen bonds are formed between the aqua ligands and the pendant oxygen atoms of the betaine ligands. In complex2, mononuclear and dinuclear cations coexist in the asymmetric unit. In the mixed-ligand complex3 the betaine ligand acts in the unidentate coordination mode andN,N,N,N-tetramethylethylenediamine (tmen) in the chelate mode. Complex4 contains a discrete centrosymmetric tetranuclear cations in which one pair of betaine ligands act in the bidentate bridging mode and the other in both bidentate and one-atom bridging modes.     

Voltammetric determination of glucose based on reduction of copper(II)–glucose complex at lanthanum hydroxide nanowire modified carbon paste electrodes

A novel voltammetric method for the determination of β-d-glucose (GO) is proposed based on the reduction of Cu(II) ion in Cu(II)(NH₃)₄²⁺–GO complex at lanthanum(III) hydroxide nanowires (LNWs) modified carbon paste electrode (LNWs/CPE). In 0.1 mol L⁻¹ NH₃·H₂O–NH₄Cl (pH 9.8) buffer containing 5.0 × 10⁻⁵ mol L⁻¹ Cu(II) ion, the sensitive reduction peak of Cu(II)(NH₃)₄²⁺–GO complex was observed at −0.17 V (versus, SCE), which was mainly ascribed to both the increase of efficient electrode surface and the selective coordination of La(III) in LNW to GO. The increment of peak current obtained by deducting the reduction peak current of the Cu(II) ion from that of the Cu(II)(NH₃)₄²⁺–GO complex was rectilinear with GO concentration in the range of 8.0 × 10⁻⁷ to 2.0 × 10⁻⁵ mol L⁻¹, with a detection limit of 3.5 × 10⁻⁷ mol L⁻¹. A 500-fold of sucrose and amylam, 100-fold of ascorbic acid, 120-fold of uric acid as well as gluconic acid did not interfere with 1.0 × 10⁻⁵ mol L⁻¹ GO determination.     

Thermal decomposition of copper(II) and zinc carbonate hydroxides by means of TG-MS

Summary For the quantitative analyses of evolved CO₂and H₂O during the thermal decomposition of solids, calibration curves, i.e. the amounts of evolved gases vs. the corresponding peak areas of mass chromatograms measured by TG-MS, were plotted as referenced by the reaction stoichiometry of the thermal decomposition of sodium hydrogencarbonate NaHCO₃. The accuracy and reliability of the quantitative analyses of the evolved CO₂and H₂O based on the calibration curves were evaluated by applying the calibration curves to the mass chromatograms for the thermal decompositions of copper(II) and zinc carbonate hydroxides. It was indicated from the observed ratio of evolved CO₂and H₂O that the compositions of copper(II) and zinc carbonate hydroxides examined in this study correspond to mineral malachite, Cu₂CO₃(OH)₂, and hydrozincate, Zn₅(CO₃)₂(OH)₆, respectively. Reliability of the present analytical procedure was confirmed by the fairly good agreement of the mass fraction of the evolved gases calculated from the analytical values with the total mass-loss during the thermal decompositions measured by TG.     

An investigation of the thermal behavior of heterobimetallic species containing copper(II) and tetracyanopalladate(II)

Synthesis, characterization and thermal behavior of four compounds that have the general formula [Cu{Pd(CN)₄}(L)_x]_n, in which en=1,2-diaminoethane and pn=1,3-diaminopropane (L=en, x=1 (I); L=pn, x=1 (II); L=en, x=2 (III); L=pn, x=2 (IV)) were described in this work. The complexes were studied by elemental analysis, infrared spectroscopy (IR), differential thermal analysis (DTA) and thermogravimetry (TG) and the residues of the thermal decomposition were characterized by X-ray powder diffraction and found as a mixture of CuO and PdO. The stoichiometry of the compounds was established via thermogravimetric and elemental analyses and their structures were proposed as coordination polymers based on their infrared spectra. The following thermal stability sequence was found: IV<I=II<III.     

Solvent Effect on the Ligand Exchange between Bis(diethyldithiocarbamato)copper(II) and Bis(diethyldiselenocarbamato)copper(II)

EPR and spectrophotometric study on the products of ligand‐exchange taking place on mixing bis(diethyldiselenocarbamato)copper(II), [Cu(Et₂dsc)₂], and bis(diethyldithiocarbamato)copper(II), [Cu(Et₂dtc)₂], solutions is reported. EPR spectra monitored at room temperature for one month period reveal a stable equilibrium among the parents (chromophores CuS₄ and CuSe₄) and the obtained mixed‐chelate [Cu(Et₂dtc)(Et₂dsc)] complex (chromophore CuS₂Se₂) in heptane, hexane, benzene, toluene, acetone, DMFA, DMSO and dichloromethane. In CCl₄ and CHCl₃ two new additional EPR spectra appear attributed to the mixed‐chelate complexes with the chromophores CuSSe₃ and CuS₃Se which are not observed with electronic spectroscopy. The intensities of all five EPR spectra decrease with the time. It is assumed that the new mixed‐chelates observed in CCl₄ and CHCl₃ are obtained in a reaction of [Cu(Et₂dtc)(Et₂dsc)] or [Cu(Et₂dtc)₂] with the ester of diselenocarbamic acid which is formed in a parallel reaction of [Cu(dsc)₂]with CCl₄ or CHCl₃.     

双氯芬酸铜(Ⅱ)、氯灭酸铜(Ⅱ)配合物合成及其清除O-2的作用

天然超氧化物歧化酶(SOD)可以专一地清除生物体内的超氧阴离子自由基O-2,从而可预防活性氧中毒、抗衰老、减少癌症等疾病的发生。但是SOD分子量大、不易透过细胞膜、在生物体内半衰期短并有异体抗原性、价格昂贵,临床使用受到很大限制。2 (2′,5′ 二氯 苯氨基) 苯乙酸(双氯芬酸)、2 (3′ 氯 苯氨基) 苯甲酸(氯灭酸)是二苯胺类衍生物,临床用作消炎镇痛药,有清除O-2的能力[1],而且活性稳定。本文制备的它们的Cu(Ⅱ)配合物,可作为SOD模拟物[2],且活性较高。1　实验部分1 1　主要试剂和仪器双氯芬酸钠(纯度99 5%河南汤阴永奈化工有限…     

Thin-layer chromatography of tris(1,10-phenanthroline)iron(II) and tris(2,2′-bipyridine)iron(II) on Sephadex G gels

Summary Gel chromatographic behaviour of tris(1, 10-phenanthroline)iron(II), tris(2,2′-bipyridine)iron(II) and tris(glycinato)cobalt(III) on Sephadex G-10 or G-25 was investigated by TLC with 0.001–1.0M NaCl as the eluent. The zone shapes and R_M values of tris(1,10-phenanthroline)iron(II) and tris(2,2′-bipyridine)iron(II) were appreciably dependent on the sample and eluent concentration, while the neutral complex, tris(glycinato) cobalt(III), exhibited the round zones with constant R_M values. The order of R_M values was found to be tris(glycinato)cobalt(III<tris(2,2∔pyridine)iron(II)<tris-(1,10-phenanthroline)iron(II) in all systems studied, although the reverse trend was expected when assuming the chromatographic behaviour of solute compounds to be controlled by the “sieving effect”. The comparison of the behaviour on Sephadex G gels with that on CM-cellulose revealed that the predominant mechanism involved is not the sieving effect, but ion-exchange and/or hydrophobic interaction.     

Thermal behaviour of hydrated copper(II) complexes

Dehydration steps of aquacopper(II) complexes with homogeneous and heterogeneous coordination sphere are investigated from the view point of structural changes taking place under their heating to the decomposition temperature and during the dehydration. The role of loosening of intra-and intermolecular hydrogen bonds in the decomposition reaction for the structure changes of the remainder, the structural presumptions of the reactants for lower hydrates formation are discussed. Activation parameters of dehydration were found to be the lower, the smaller are the structure differences between the reactants and products. They do not reflect the bond length central atomvolatile ligand, much more the overall structure differences between the starting and resulting compounds. From all data on crystal and molecular structures of dehydrated compounds is the reaction pathway best indicated by anisotropic temperature parameters of donor atoms corrected for the thermal movement of the central atom: the higher these values in the bond direction are, the lower the values of activation energies of dehydration are.     

Synthesis of ditopic ligands for the selective extraction of copper(II) nitrate and crystal structures of their Cu(II) complexes

We have synthesized two ditopic ligands for selective extraction of copper(II) nitrate. We also synthesized one cation-only binding analog for comparison. All three ligands were characterized by conventional techniques. Competitive two-phase metal ion solvent extraction experiments were performed at 25 °C over a period of 24 h. These ligands showed significant selectivity for Cu(II) ions, having the ditopic ligands extract 81 and 73% of the Cu(II) ions in a solution of different metal ions {Ni(II), Co(II), Cu(II), Zn(II), Cd(II), Pb(II)} at pH 5.09. Competitive transport experiments (water/chloroform/water) were undertaken employing each ligand separately as the ionophore in the membrane (chloroform) phase. No metal ion transport was observed, but a large concentration of Cu(II) was present in the membrane phase. Competitive anion extraction and transport were carried out with the ditopic ligands, yielding selective extraction and transport of nitrate. Furthermore, a pH isotherm of the best ditopic ligand (H₂L²) with Cu(II) was determined from pH 1.0 to 6.0, producing a pH_½ value of approximately 2.6. Finally, crystal structures of the ditopic ligands complexed with Cu(II) were determined and refined. The coordination geometry around the metal centers are distorted square planar and the Cu(II)-donor bond lengths fall within the normal range.     

Synthesis,characterization and biological properties of novel ON donor bidentate Schiff bases and their copper(II) complexes

Four novel ON donor Schiff bases (E)-3-((4-phenoxyphenylimino)methyl)benzene-1,2-diol (HL₁),(E)-3-((4-(4-biphenyloxy)phenyliminomethyl)benzene-1,2-diol (HL₂), (E)-3-((4-naphthoxyphenylimino)methyl)benzene-1,2-diol (HL₃), (E)-3-((4-(2-naphthoxy)phenylimino)methyl)benzene-1,2-diol (HL₄) and their copper(II) complexes bis((E)-3-((4-phenoxyphenylimino)methyl)benzene-1,2-diol) copper(II) (Cu(L₁)₂) bis((E)-3-((4-(4-biphenyloxy)phenylimino)methyl)benzene-1,2-diol) copper(II) (Cu(L₂)₂), bis((E)-3-((4-naphthoxyphenylimino)methyl)benzene-1,2-diol) copper(II) (Cu(L₃)₂), bis((E)-3-((4-(2-naphthoxy)phenylimino)methyl)benzene-1,2-diol) copper(II) (Cu(L₄)₂) have been synthesized and characterized by spectroscopic (FTIR, NMR, UV–visible) and elemental analysis. The crystal structures of HL₁, HL₂, HL_3, and HL₄ have been determined, which reveal intramolecular N-H?O (HL₁, HL₂, HL_3, and HL₄) hydrogen bonds in the solid state. Keto-amine and enol-imine tautomerism is exhibited by the Schiff bases in solid and solution states. The Schiff bases and their copper(II) complexes have been screened for their biological activities. In antimicrobial assays (antibacterial and antifungal), HL₄ showed promising results against all strains through dual inhibition property while the rest of the compounds showed activity against selective strains. On the other hand, in cytotoxic, DPPH, and inhibition of hydroxyl (OH) free radical-induced DNA damage assays, the results were found significantly correlated with each other, i.e. the ligands HL₁ and HL₂ showed moderate activity while their complexes Cu(L₁)₂ and Cu(L₂)₂ exhibited prominent increase in activity. As the results of these assays are supporting each other, it represents the strong positive correlation and antioxidant nature of investigated compounds.     

New copper(II) and zinc(II) complexes based on azo Schiff base ligand: Synthesis,crystal structure,photoisomerization study and antibacterial activity

Newly synthesized mononuclear copper(II) and zinc(II) complexes containing an azo Schiff base ligand (L), prepared by condensation of 2-hydroxy-5-(o-tolyldiazenyl)benzaldehyde and propylamine, were obtained and then characterized using infrared and NMR spectroscopies, mass spectrometry and X-ray diffraction. Ligand L behaves as a bidentate chelate by coordinating through deprotonated phenolic oxygen and azomethine nitrogen. The copper and zinc complexes crystallize in triclinic and orthorhombic systems, respectively, with space groups P⁻1 and Pca2₁. In these complexes, the Cu(II) ion is in a square planar geometry while the Zn(II) ion is in a distorted tetrahedral environment. The photochemical behaviors of ligand L, [Cu(L)₂] and [Zn(L)₂] were investigated. The azo group in L underwent reversible trans–cis isomerization under UV and visible irradiation. This process was inhibited for the complexes. In addition, ligand L and its copper and zinc complexes were assessed for their in vitro antibacterial activities against four pathogenic strains.     

Synthesis, crystal structure, spectroscopic and photoluminescence studies of manganese(II), cobalt(II), cadmium(II), zinc(II) and copper(II) complexes with a pyrazole derived Schiff base ligand

Varying coordination modes of the Schiff base ligand H₂L [5-methyl-1-H-pyrazole-3-carboxylic acid (1-pyridin-2-yl-ethylidene)-hydrazide] towards different metal centers are reported with the syntheses and characterization of four mononuclear Mn(II), Co(II), Cd(II) and Zn(II) complexes, [Mn(H₂L)(H₂O)₂](ClO₄)₂(MeOH) (1), [Co(H₂L)(NCS)₂] (2), [Cd(H₂L)(H₂O)₂](ClO₄)₂ (3) and [Zn(H₂L)(H₂O)₂](ClO₄)₂ (4), and a binuclear Cu(II) complex, [Cu₂(L)₂](ClO₄)₂ (5). In the complexes 1-4 the neutral ligand serves as a 3N,2O donor where the pyridine ring N, two azomethine N and two carbohydrazine oxygen atoms are coordinatively active, leaving the pyrazole-N atoms inactive. In the case of complex 5, each ligand molecule behaves as a 4N,O donor utilizing the pyridine N, one azomethine N, the nitrogen atom proximal to the azomethine of the remaining pendant arm and one pyrazole-N atom to one metal center and the carbohydrazide oxygen atom to the second metal center. The complexes 1-4 are pentagonal bipyramidal in geometry. In each case, the ligand molecule spans the equatorial plane while the apical positions are occupied by water molecules in 1, 3 and 4 and two N bonded thiocyanate ions in 2. In complex 5, the two Cu(II) centers have almost square pyramidal geometry (τ = 0.05 for Cu1 and 0.013 for Cu2). Four N atoms from a ligand molecule form the basal plane and the carbohydrazide oxygen atom of a second ligand molecule sits in the apex of the square pyramid. All the complexes have been X-ray crystallographically characterized. The Zn(II) and Cd(II) complexes show considerable fluorescence emission while the remaining complexes and the ligand molecule are fluorescent silent.     

Synthesis and properties of the chain-like polymeric copper (II) complexes bridged by bis(diphenylphosphino oxide)ethane

At room temperature, the chain-like polymeric copper (II) complexes bridged by bis (diphenylphosphino oxide) ethane (dppeO2), [Cu(dppeO2)X2]n[X=Cl(1), Br(2)] have been prepared and characterized by elemental analysis, 31P NMR, TG-DTA and X-ray analysis for [ CuBr2 (dppeO2) ] n The chain is composed of subunits containing tetrahedron coordinated copper (II) atoms. The four-coordinated copper (II) atom is ligated to another four-coordinated copper (II) atom through dppeO2. The coordination sphere of copper(II) atom is completed by two monodentate bromide and two oxygen atoms from bridging dppeO2. Crystal data are as follows: C26-H24CuP2BnO2, 0.50 mm× 0.40 mm×0.40 mm, monoclin-ic, space group: C2/c, λ= 0.07107 nm(Mo Ka), a = 1.2286(2) nm, b=2.0555(8) nm, c = 1.0652(2) nm, β = 97.366(9)°, V = 2.668nm3, Z = 4, Dcalc = 1.628 g·cm-3, R = 0.066; Rw = 0.091.     

Coprecipitation of Amino Acids with Mixed Hydroxide of Iron(III) and Copper(II)

Abstract

A coprecipitation method for concentrating amino acids from aquatic environments with a mixed hydroxide of iron(III) and copper(II) was developed. The percent coprecipitation of glycine, alanine, glutamic acid, aspartic acid, and lysine, being independent of pH in the range of 8.5 to 9.5, was more than 95%.     

Synthesis,spectral characterization,anticancer and antibacterial studies of cyclodiphosph(V)azane derivatives and their copper(II) complexes

The new cyclodiphosph(V)azane derivatives (1,3-dimethyl-2,4-dioxo-2',4'-bis(2,4-bis(dimethylaminopropylimino)cyclodiphosph(V)azane (H₂L¹) (1,3-dimethyl-2,4-dioxo-2',4'-bis(2,4-bis(dimethylaminoethylimino)cyclodiphosph(V)azane (H₂L²) and (1,3-dimethyl-2,4-dioxo-2'-(dimethylaminoethylimino)-4'-(dimethylaminopropyl-imino)cyclodiphosph(V)azane (H₂L³) containing four active coordination centers (NNNN) and their Cu(II) complexes have been synthesized and characterized by elemental analyses, spectroscopic methods, molar conductance as well as thermal and magnetic measurements. The UV–Vis and mass spectra of the ligands and their Cu(II) complexes were also recorded. The copper(II) complexes were found to have magnetic moments of 1.58–1.69 B. M. corresponding to one unpaired electron. The possible geometries of the complexes were assigned on the basis of EPR, electronic, and infrared spectral studies. The absence of water molecules in all complexes was supported by thermal studies. All the thermal decomposition processes ended with the formation of CuO. The kinetic and thermodynamic parameters have been calculated. The ligand (H₂L³) and its Cu(II) complexes were screened for their anticancer studies against human breast cancer cell lines MCF-7 and minimum inhibitory concentration was calculated. The screening was extended to the antibacterial activity using Kirby–Bauer single disk susceptibility test for all compounds.     

Thiocyanate-selective electrode based on N-salicylidene-benzylamineato copper(II) complex

Highly selective poly(vinyl chloride) (PVC) membrane electrode based on N-salicylidene-benzylamineato copper(II) complexes [Cu(SBA)₂] as new carriers towards thiocyanate-selective electrode was reported. The influence of membrane composition, pH and possible interfering anions were investigated on the response properties of the electrode. The resulting electrode exhibits anti-Hofmeister selectivity sequence: SCN⁻ > ClO₄⁻ > Sal⁻ > I⁻ > Br⁻ > NO₃⁻ > NO₂⁻ > SO₃²⁻ > H₂PO₄⁻ > Cl⁻ > SO₄²⁻, and a near-Nernstian potential linear range for thiocyanate from 1.0 × 10⁻¹ to 9.0 × 10⁻⁷ M with a detection limit of 7.0 10⁻⁷ M and a slope of , over a wide pH range of 3.0–9.0 in phosphate buffer solution at 20°C. The proposed electrode has a fast response time of about 5–10 s and can be used for at least 3 months without any considerable divergence in potential. The electrode was successfully applied to the determination of thiocyanate in waste water and human urine and saliva samples. Published in Russian in Elektrokhimiya, 2008, Vol. 44, No. 3, pp. 293–299. The text was submitted by the authors in English.