Electrochemical behavior of Cu(II) reduced in CH3OH and DMSO

The cyclic voltammetry and the potential-time curve after galvanostaticelectrolysis were used to study the electrode processes of Cu(II) in CH_3OH solution and DMSOsolution. The electroreduction of Cu(II) to Cu on a Pt electrode proceeds in two steps: Cu(II) + evelence Cu(I); Cu(I) + e velence Cu. The reduction potential of Cu(II) in DMSO solution is morenegative than that in CH_3OH solution, and the diffusion coefficient of Cu(II) ion in DMSO solutionis larger than that in CH_3OH solution because the polarity of DMSO is larger than that of CH_3OHobservably and has a stronger solvating power.

Adsorption of Cu(II) on maghnite from aqueous solution: Effects of pH, initial concentration, interaction time and temperature

The adsorption behaviour of Cu2+ onto maghnite was conducted under batch conditions. The effect of time, pH of the dispersion, temperature and initial metal concentration on the adsorption of Cu2+ onto maghnite was investigated. In this study, 94% of Cu(II), was adsorbed on the maghnite clay when the equilibrium was reached at 120 min. The adsorption of Cu2+ was a fast process that followed the pseudo-second-order kinetics. This process could be described by the Langmuir model and gave a maximum Cu2+ adsorption capacity of 21.78 mg/g at 293 K. The thermodynamic parameters such as variation of enthalpy ΔH, variation of entropy ΔS and variation of Gibbs free energy ΔG were calculated from the slope and intercept of lnKd vs. 1/T plots. The adsorption was endothermic reaction. The adsorption process for this natural maghnite is more spontaneous because the values of ΔG are less negative. The results suggested that natural maghnite was suitable as sorbent material for the recovery and adsorption of metal ion from aqueous solutions.

Spectrofluorimetric method for determination of some angiotensin II receptor antagonists

A simple, rapid, accurate and highly sensitive spectrofluorimetric method has been developed for determination of some angiotensin II receptor antagonists (AIIRA’s), namely Losartan potassium (Los-K), Irbesartan (Irb), Valsartan (Val) and Candesartan cilexetil (Cand) in pure forms as well as in their pharmaceutical dosage forms. All the variables affecting the relative fluorescence intensity (RFI) were studied and optimized. Under the optimum conditions, linear relationships with good correlation coefflcients (0.9982–0.9991) were obtained over the concentration range from 0.006 mg/mL to 1.7 mg/mL. Good accuracy and precision were successfully obtained for the analysis of tablets containing each drug alone or combined with hydrochlorothiazide (HCTZ) without interferences from the co-formulated HCTZ or the additives commonly present in tablets.

Synthesis and Crystal Structure of a Dinuclear Cu(II) Complex with Tridentate Schiff Base and Azido Bridge

A new dinuclear copper(II) complex ([Cu(C12H17N2O)(N3)]2, C24H34Cu2N10O2) has been synthesized and characterized by X-ray structure determination. It crystallizes in the monoclinic system, space group P21/c with a = 18.529(4), b = 10.933(2), c = 14.534(3) ?, β = 111.07(3)°, V = 2748(1) ?3, Z = 4, Mr = 621.69, F(000) = 1288, Dc = 1.503 g/cm3 and μ(MoKα) = 1.590 mm?1. The structure was refined to R = 0.0647 and wR = 0.1846 for 4406 observed reflections (I > 2σ(I)). The asymmetric unit comprises two halfmolecules. The complex is a centrosymmetric dimmer in which the copper atoms are penta-coordinated by three coordination atoms from the corresponding tridentate Schiff base ligand and two bridging azide anions. The Cu(II)…Cu(II) average distance is 3.350(1) ?.

Synthesis,Structure and Properties of a Novel Copper(Ⅱ)-2,2'- biimidazole Complex-supported Compound:[Cu(H_2biim)_2]{[Cu(H_2biim)_2 ]_2[H_(10)W_(12)O_(44)]}·8H_2O

A new copper（II）-2,2＇-biimidazole metal-organic POMs-supported compound [Cu（H2biim）2]{[Cu（H2biim）212[H10W12O44]}＇8H2O （H2biim = 2,2＇-biimidazole） has been success- fully synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis and TG. The crystal adopts space group Pi with a = 11.800（2）, b = 13.437（3）, c = 13.685（3） A, V = 1922.5（7） A3, D,. = 3.507 g/cm3, C36H62Cu3N24W12O52, M,. = 4059.92, F（000） = 1837,μ = 18.796 mm-1, Z = 1, R = 0.0579 and wR = 0.1465 for 8734 observed reflections （I 〉 2σ（I））. X-ray crystallography analysis exhibits that the title compound consists of one [H10W12044]6- polyanion and three [Cu（H2biim）2] units. And significant π-π stacking interactions and intermolecular O-H-,.O or N-H.＇-O hydrogen-bonding interactions lead to a three-dimensional supramolecular framework. Thermal stability and magnetic property of the complex have also been investigated.

Atomic Absorption and Vibrational Spectral Magnetic Studies on the Removal of Cu(II) and Co(II) Ions Using Synthetic Nano Adsorbent Fe₃O₄

Adsorption of Cu(II) and Co(II) from aqueous solutions on synthetic nano Fe3O4 has been studied. The effect of experimental parameters such as initial concentration of the metal ions, adsorbent dosage, contact time and pH has been investigated. Optimum removal efficiency of Cu(II) ion was found to be 97.8% with the dose rate of 1.07 g/L in 60 minutes at pH = 5.5 and for Co(II) ion, it was found to be 99.2% with the dose rate of2.57 g/L in 10 minutes at pH = 5.4. The removal of Co(II) ions require only 10 minutes with the efficient removal of 99.2%, whereas Cu(II) ions require 60 minutes with the maximum removal of 97.8%. In order to understand the effective removal of Cu(II) and Co(II) ions on Fe3O4, room temperature magnetic measurement was carried out using Vibrational Spectrum Magnetometer (VSM), before and after adsorption with a maximum applied magnetic field of 20,000 G.

Biosorption of Cu(II) Ions from Aqueous Solution by Red Alga (<i>Palmaria Palmata</i>) and Beer Draff

In this study, the ability of red alga (Palmaria palmata) and beer draff (brewery waste) for Cu(II) removal was investigated. The influence of factors, such as pH, initial copper concentrations, and contact time, were also studied. Results showed the adsorption process was strongly dependent on the pH value and initial concentration. The optimum pH value was in the range of 5-6. The Langmuir isotherm model performed better than other models, suggesting monolayer adsorption prevailed in the adsorption process. The theoretical adsorption capacities for Cu(II) were 12.7 mg/g and 9.01 mg/g for red alga and beer draff, respectively. The spectroscopy analyses and desorption studies showed that chemical bonding was the main mechanism in the adsorption process rather than ion exchange. The functional groups of amino, hydroxyl, carboxyl, phenolic hydroxyl, sulphonic group and C–O, –NH stretch might be involved in adsorption. After adsorption, both materials were successfully regenerated by nitric acid at a concentration of 10 mmol/L. Furthermore, the phenomenon that only 7% of adsorbed Cu(II) on red alga and 11% on beer draff were desorbed by sodium chloride solution suggested potential alternative of both materials for the treatment of road runoff containing considerable amounts of de-icing salt.

Comparative Studies of Some Novel Cu(II) Polymeric Complexes Derived from Cyanoacetylhydrazine (CAH;L). The Role of Solvents Used on the Structure and Geometry of the Isolated Cu²⁺Complexes

Novel polymeric Cu2+ complexes derived from the reaction of cyanoacetylhydrazine (CAH;L) with CuCl2•2H2O in different solvents were synthesized and characterized. The isolated solid polymeric complexes were investigated using modern conventional physicochemical and spectral (IR, 1H-NMR, UV-Vis. ESR, Raman), magnetic and thermal studies. The results revealed that CAH behaves in different ways towards the coordination of the Cu2+ ion. The promotion of solvents to the cyano group was discussed on the basis of the solvent and the Cu2+ ion used. Magnetic and spectral studies suggest octahedral geometry is proposed for the Cu2+ complexes. EPR studies indicate the existence of polymeric complexes depending on the results of g-values. The results suggest that the number of copper atoms ranges from three to twelve atoms. The molecular modeling is drawn and some chemical characteristics are calculated such as chemical reactivity and energy components are investigated between the different types of the ligands.

Mechanistic Study and Kinetic Determination of Cu(Ⅱ) by the Catalytic Kinetic Spectrophotometric Method

A highly sensitive and selective catalytic kinetic spectrophotometric method for the determination of Cu(Ⅱ) is proposed. It is based on the catalytic effect of Cu(Ⅱ) on the oxidation of glutathione(GSH) by potassium hexacyanoferrate(Ⅲ) in acidic medium at 25.0℃. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of oxidant at 420 nm using the fix-time method. Under the optimum conditions, the proposed method allows the determination of Cu(Ⅱ) in a range of 0-35.0 ng m L^(-1) with good precision and accuracy and the limit of detection is down to 0.04 ng m L^(-1). The relative standard deviation(RSD) is 1.02%. The reaction orders with respect to each reagent are found to be 1, 1/2, and 1/2 for potassium hexacyanoferrate(Ⅲ), glutathione and Cu(Ⅱ) respectively. On the basis of these values, the rate equation is obtained and the possible mechanism is established. Moreover, few anions and cations can interfere with the determination of Cu(Ⅱ). The new proposed method can be successfully used to the determination of Cu(Ⅱ) in fresh water samples and seawater samples. It is found that the proposed method has fairly good selectivity, high sensitivity, good repeatability, simplicity and rapidity.

Investigati on sonsimultaneous determination of silver and mercury in catalytic－ligandsub stitution reaction with stopped－flow technique calibrated by synergistic effect

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The Simultaneous Determination of Cu Ph Cd and Sb by Derivative Adsorption Chronopotentiometry

The behaviour of the complexes of copper,lead,cadmium and antimony with salicylfluorone (SAF) adsorbed on HMDE has been investigated by derivative chronopotentiometry in NH_3/NH_4C1. The dependence of the peak height on the dt/dE vs E curve on preconcentration time, the pH of solution and the constant reducing current are discussed. This method achieved the simultaneous determination of copper, lead, cadmium and antimony in human hair.

Synthesis and Crystal Structure of a Dinuclear Cu(II) Complex [Cu(C_(12)H_(17)N_2O)(NCS)]_2 with Tridentate Schiff Base Ligand N-(Salicylidene)-3-dimethylaminopropylamine

A new dinuclear copper(II) complex (Cu(C12H17N2O)(NCS)2, C26H34Cu2N6O2S2) has been synthesized and characterized by X-ray structure determination. It crystallizes in the triclinic system, space group P1 with a = 11.289(2), b = 12.071(2), c = 12.113(2) ?, α = 72.90(3), β = 83.76(3), γ = 65.60(3)°, V = 1436.7(5) ?3, Z = 2, Mr = 653.79, F(000) = 676, Dc = 1.511 g/cm3, μ(MoKα) = 1.660 mm?1, the final R = 0.0334 and wR = 0.0856 for 5047 observed reflections (I > 2σ(I)). The asymmetric unit comprises two half-molecules. The complex is a centrosymmetric dimmer in which each copper(II) is coordinated in the equatorial plane to the N-(salicylidene)-3- dimethylaminopropylamine ligand through the deprotonated phenolic oxygen atom as well as the nitrogen atoms of imine and amine. The fourth coordination site is occupied by the nitrogen atom of NCS?, while the axial one by the symmetrically related phenoxy oxygen of the other monomeric unit. The Cu(II)…Cu(II) average distance is 3.110(1) ?.

SIMULTANEOUS DETERMINATION OF Cu(Ⅱ),Zn(Ⅱ),Fe(Ⅱ),Mn(Ⅱ),Co(Ⅱ) AND Ni(Ⅱ) WITH A SINGLE SWEEP POLAROGRAPHY

A new method of simultaneous determining Cu(Ⅱ), Zn(Ⅱ), Fe(Ⅱ), Mn(Ⅱ), Co(Ⅱ)and Ni(Ⅱ) with a single sweep polarography was developed. The experiment condition was studied and the results shou that the optimum base solution is that the residue got from evaporating 25 mL mixed solution, 2.5 mL 1.0 mol/L ethylenediamine, 3.0 mL 1 .0 mol/L ammonia-ammonium chloride,5.0mL, 10 % sodium sulfite and 0.5 mL 0.5 % gelatin were mixed and diluted to 25 mL, with water.Under the condition of this base solution, the polarography wave shapes of the six cations are ideal and without overlap of the peaks. In this base solution, Cu(Ⅱ), Zn(Ⅱ), Fe(Ⅱ), Mn(Ⅱ). Co(Ⅱ) and Ni(Ⅱ)in synthetic samples were determined with relative errors 0.4-9.4 % and relative standard deviations 0.8%- 12.2%. Under this experiment condition, one fold of Pb(Ⅱ), Cr(Ⅵ) and Mo(Ⅵ ) do not interere with the determination for Cu(Ⅱ). This method has been used to the simultaneous determination of the amount of the six cations in the samples of soil and Beiqi Tea. The relative standard deviations were 0.1%-2.1 % and recoveries were 93.5%-99.0 %.

Spectrophotometric Determination of Cu（Ⅱ） in Anolyte of Electrolytic Nickel by EDTPO

N, N, N′,N′-ethylenediaminetetrakis(methylenephosphonic acid), EDTPO, was synthesized and char-acterized by element analysis. The reaction of EDTPO with Cu(Ⅱ) formes a stable blue complex with a molarabsorptivity of 2. 88 × 10￣3 L· mol￣(-1)· cm￣(-1) at 285. 1nm. The composition of the complex is determined tobe 1: 1 . The concentration of Cu (Ⅱ)obeys the Beer′s law from 12. 7μg/ml to 50. 8 μg/ml .Co(Ⅱ), Mn(Ⅱ), Pb(Ⅱ), Cd(Ⅱ), Ca(Ⅱ), Mg (Ⅱ), Cr (Ⅱ) cause a negligible interference except forFe(Ⅱ), Zn(Ⅱ) in the determination of Cu (Ⅱ) with EDTPO. The spectrophotometric determinationof Cu(Ⅱ) is developed. This method is successfully used in determination of Cu(Ⅱ)in anolyte of electrolyticnickel.

Synthesis and Determination of Stability Constants of a New Bis-1,2,4-triazole Ligand for Complexation with Zinc(II), Copper(II) and Nickel(II) in Acetonitrile

In this work, the synthesis and complexation properties of a new compound, 1,3-bis[5-(2-hydroxyphenyl)-4-phenyl- 1,2,4-triazole-3-yl-thio]propane (BTP), towards certain transition metal ions, (M(II) where M = Zn, Cu, Ni) in acetonitrile is reported. A hard-modeling strategy was applied to UV-Visible spectroscopy data obtained from monitoring the reaction between BTP and the selected metal ions to determine the concentration profiles of each species and the corresponding stability constant(s) of the complex(es). The stability constants of complexes are always defined in terms of their free metal, free ligand and complexed forms. These constants are influenced by parameters such as the type of metal, ligand, counterion or solvent. In this study, the formation constants of the complexes were determined for the synthesized ligand with several metallic cations in acetonitrile solvent by UV-Vis spectrophotometry.

SYNTHEIS, SITUCTURE AND CHARACTERIZATION OF BINUCLEAR Cu(II)COMPLEX[Cu(C_6H_5COO)_2(C_5H_6N_2)]_2.(C_4 H_8O)_2

At room temperature,dibenzoyl peroxide undergoes oxidative addition on metallic Copper Powder and 2-aminopyridine in a solvent(acetone and tetrahydrofuran), which affords the product as a binuclear Cu(II)complex [Cu (C5 H5 COO)2(C5 H5 N2)]2. (C4 H5 O)2. The structure of the complex was characterized by elemental analyses. IR spectra, TG-DTA. The structure of the compound has been solved by direct method and Fourier synthesis, and refined by block-diagonal and full matrix least-squares method to a final R of 0.04329 for 3671 independent reflection of I>e(I). The crystals are triclinic, C46H45N4O10Cu2.Z=1, Mr=943.93, space group P-1, with cell parameters, a=10.806(1); b=11.169(3);c=11.729(2)A; α=71.99(2),β=89.38(1)°; γ=81.37(1); V=1330.1A3; Dc=1.172g.cm-3;μ=8.5cm-1. The copper(II) ion is coordinated by four bridging bidentate benzoate and two 2-aminopyridine to form dimeric molecules.

CRYSTAL STRUCTURE OF A 2D SHEET－LIKE μ－CYANIDO－OXAMIDATO BRIDGED Fe（III）－Cu（II） HETERNUCLEAR COMPLEX

The synthesis is and crystal structure are reported for the sheet-like compourd [CU2(oxpn)Fe(CN )5(NO)]. there oxpn is the dianion of M, M'-bis(3-aminopropyl)oxamide. This compound crustallizes in the orthogonal space group Puma. with a=11 .413(4), b=22.242(5), c=7.736(2) A, and Z=4.The structure was refined to conventionat discrepancy factors R=0.047 and Pw=0.054. The Cu(II ) and Fe(III)centers are bridged by oxpn and cyanide, the formal behaves as a his-terdentate tigand bound to cooper(II)ion to form (II) dimers. whereas the latter bridges Cu(II) and Fe(III) centers in both symmetric and asymetric end- to-end bis-monodentate fashions, spreading out along be plane to form a 20 network. The Structure is made up of CuFe unit with Cu(II) and Fe(III) ions locating in a distorted square-based pyramid and a compressed octahedron, respectively.

Synthesis and Crystal Structure of Cu(II) Complex with 2,9-Bis(n-2',5'-diazaheptanyl)-1,10-phenanthroline

The Cu(II) complex with the ligand 2,9-bis(n-2?5?diazaheptanyl)-1,10-phenan- throline (L) has been synthesized and characterized by single-crystal X-ray diffraction. It crys- tallizes in the monoclinic system, space group P21/n with a = 12.549(4), b = 13.544(4), c = 16.767(5) ? = 107.179(5), C22H32Cl2N6CuO8, Mr = 642.98, V = 2722.5(13) 3, Z = 4, Dc = 1.569 g/cm3, ?= 1.056 mm-1, F(000) =1332, the final R = 0.0733 and wR = 0.1581. The X-ray analysis revealed that the Cu(II) ion is coordinated by six nitrogen atoms of the ligand, in which two nitrogen from phenanthroline and another two from the imine groups near phenanthroline are in the equatorial plane while the two from imine groups at the end of both arms in the axial positions. The coordination geometry can be described as a compressed octahedron.

SYNTHESIS AND CARACTERIZATION OF TERNARY COMPLEXES CONTAINING Cu(II),L-HISTIDINE AND NUCLEOTIDE

The ternary complexes containing Cu(II),L-His and nucleotide (5'-GMP and 5'-IMP)were synthesized and characterized.IR and ~1H NMR spectra show that Cu(II)binds to carboxylate oxygen and imidazole nitrogen of L-His and purine N_7 of 5'-GMP and 5'-IMP.The interaction of Cu(II)with Po_3^(2-)of 5'-GMP is present,but that for 5'-IMP is not present.

Cu(II)在对甲苯磺酸铜+DMSO中的电还原

制备了对甲苯磺酸铜并首次用于电化学实验.差示扫描量热和热重曲线测定表明,对甲苯磺酸铜结晶容易脱除全部结晶水,无水盐在空气中不潮解.用循环伏安曲线、计时电流曲线和恒电流电解后的电位-时间曲线研究Cu(Ⅱ)在二甲基亚砜(DMSO)溶液中的电还原.结果表明,Cu(II)电还原为Cu的反应分两步进行,其中第一步是可逆过程.测定了Cu(II)在DMSO溶液中的扩散系数.