The interactions of Cu(II) in Cu(II)-exchanged K-L gallosilicate with adsorbates containing coordinative nitrogens in ammonia, pyridine, aniline, acetonitrile and hydrazine, and with the adsorbates carbon monoxide, benzene, propanol and dimethyl sulfoxide are investigated by electron spin resonance (ESR) and electron spin echo modulation (ESEM) spectroscopies. These results are compared with those in Cu(II)-exchanged K-L aluminosilicate and the differences are discussed. Adsorption of ammonia produces a complex containing four molecules of ammonia based on resolved nitrogen superhyperfine interaction. Upon equilibrium with pyridine, Cu(II) forms a complex containing four molecules of pyridine in CuK-L gallosilicate and a complex containing only three molecules of pyridine in CuK-L aluminosilicate based on resolved nitrogen superhyperfine. Upon adsorption of aniline and acetonitrile, Cu(II) forms complexes containing two molecules of each in CuK-L gallosilicate based on resolved nitrogen superhyperfine. However, no resolved nitrogen superhyperfine between hydrazine and Cu(II) is seen. Adsorption of carbon monoxide, benzene, propanol and dimethyl sulfoxide causes changes in the ESR spectrum of Cu(II), indicating migration of Cu(II) into cation positions in the main channels where adsorbate coordination can occur. Cu(II) forms complexes with one molecule of benzene and two molecules of propanol based on ESEM data in both K-L gallosilicate and K-L aluminosilicate. However, Cu(II) interacts directly with one dimethyl sulfoxide in K-L aluminosilicate but only indirectly at a longer distance with one dimethyl sulfoxide in K-L gallosilicate based on ESEM data. 相似文献
Abstract The Cu(III) oxides were investigated first for the unusual copper oxidation state and then for the high-Tc superconductivity. In the last case this property is observed when a mixed copper valence is stabilized : Cu(I)/Cu(II) or Cu(II)/Cu(III). A new mixed valence Cu(III)/Cu(IV) has been stabilized in the three dimensional lattice of the perovskite-type oxide Lal-xSrxCuO3 (0 ≥ ′ ≥ 0,25). Chemical analysis and XPS study confirm the mixed valence. This compound shows metallic properties with an broadening of the conduction band compared to LaCu03. Such a behaviour can be explained either by the increase of the covalence of the average Cu-0 bond or by the decrease of the structural distortion induced by the substitution of Sr(II) for La(III). No superconducting property has been detected down to 4K. 相似文献
Summary Positronium reactions with Cu(II) ions in aqueous solution were investigated by measuring the concentration dependence of
lifetime spectra and of 1D-ACAR curves for the following Cu (II) complexes: [Cu(H2O)6[2+, [Cu(NH3)4 (H2O)2]2+ and [Cu(EDTA)(H2O)]2−. The combined analysis of lifetime and ACAR data shows that Cu(II) ions:a) reduce the formation of positronium (inhibition effect),b) promote both ortho ⇌ para conversion and redox reactions. It was also found that inhibition and reaction rate constants
are affected by the ligand type. 相似文献
Single-crystal Electron Paramagnetic Resonance (EPR) and optical absorption studies were performed at room temperature on Cu(II)-ion–doped bis-glycine sodium nitrate, a semiorganic nonlinear optical material (NLO). Spin-Hamiltonian parameters, obtained from single-crystal EPR spectra, recorded in three mutually orthogonal planes, revealed the presence of two magnetically inequivalent Cu(II) sites. Molecular orbital parameters were also evaluated. The optical absorption spectrum at room temperature exhibits the lowering of octahedral symmetry to an axially elongated tetragonal of Cu(II) ion in NLO. 相似文献
Hydrogels based on cellulose-graft-poly (acrylic acid) copolymers (C-g-AA) were synthesized by graft copolymerization in a phosphoric acid solvent. Fourier transform infrared (FT-IR) spectra confirmed the structure of the C-g-AA. The adsorption behaviors of the hydrogels for Cu(II) and Ni(II) were investigated. The results showed that their adsorption capacity increased as the initial concentrations of metal ions and the pH value of the solution increased. Freundlich and Langmuir isotherm models were employed to analyze the data from batch adsorption experiments. The results indicated that there were very good correlation coefficients for their linearized equations. The maximum adsorption amounts of the hydrogels for the metal ions, based on the Langmuir model, were 182 and 200 mg/g for Cu(II) and Ni(II), respectively. When the initial concentration of metal ions was 1000 mg/g the actual adsorption amounts of the hydrogels for Cu(II) and Ni(II) were 181 and 183 mg/g, respectively. 相似文献
Kaolinite-bearing clay samples from Perus, São Paulo state, Brazil, were used for chemical modification process with dimethyl sulfoxide and organofunctionalized with the silyating agent (RO)3Si(CH2)3NH(CH2)2NH2 in the present study. The resulting material and natural kaolinite were subjected adsorpion process with Cu(II) and Zn(II) from aqueous solution at pH 6.0 and controlated temperature of 298 K. The Langmuir adsorption isotherm model has been applied to fit the experimental data. The results showed that the chemical modification process increases the basal spacing of the natural kaolinite from 0.711 to 0.955 nm. The energetic effects caused by Cu(II) and Zn(II) interactions were determined through calorimetric titration at the solid–liquid interface and gave a net thermal effect that enabled the calculation of the exothermic values and the equilibrium constant. 相似文献
A fluorescence sensor for selective detection of Cu(II) is realized by covalently immobilizing derivatives of rhodamine6G (R6G) on the surface of silicon nanowires (SiNWs). It features the release of R6G from the SiNWs in the presence of Cu(II), which causes a significant enhancement of the fluorescence over other metal ions. The present Cu(II) sensor has good selectivity and sensitivity, and exhibits a linear response in the range of 0.0-7.0 μM Cu(II). Different from conventional Cu(II) sensor with fluorescence quenching, the present sensor based on fluorescence enhancement facilitates the practical application. Especially, the release of the R6G from SiNWs could be utilized as fluorescent labeling for Cu(II) in microenvironment. 相似文献
An “off-on” rhodamine-based fluorescence probe for the selective signaling of Cu(II) and Fe(III) has been designed and synthesized.
The optical properties of this compound have been investigated in acetonitrile-water (1:1) binary solution. Very interestingly,
this compound showed sensitivity and selectivity towards Cu(II) during absorption process and towards Fe(III) during emission
process. So this is a nice example of an excellent dual chemosensor for two biologically/physiologically very important transition metal ions using only the two very different techniques
(absorption and emission); both cases displayed only intensity enhancement. 相似文献
This paper addresses the geometry of the catalytic Cu(II) complexes formed in the course of stereoselective Diels–Alder reaction. The parent catalyst is [Cu(II)-isopropyl-pybox](OTf)2. Ethyl glyoxylate serves as dienophile and it reacts with 1,3-cyclohexadiene. The reaction is followed by CW EPR, HYSCORE, and (pulsed) ENDOR spectroscopy and the experimental results are supported by DFT computations. It is shown that during the catalytic process, the Cu(II) complex is pentacoordinated and one of the triflate counterions is coordinated to the Cu(II) center in axial position. 相似文献
Novel Supramolecular fluorescence receptor derived from calix-system i.e. calix[4]resorcinarene bearing dansylchloride as fluorophore was designed and synthesized. The compound was purified by column chromatography and characterized by elemental analysis, NMR and Mass spectroscopy. Tetradansylated calix[4] resorcinarene (TDCR) shows a boat conformation with C2v symmetry. The complexation behaviour of metal cations [Ag(I), Cd(II), Co(II), Fe(III), Hg(II), Cu(II), Pb(II), Zn(II), U(VI) (1?×?10-4?M)] with tetra dansylated calix[4]resorcinarene (1?×?10-6?M) was studied by spectophotometry and spectrofluorometry. Red shift in the absorption spectra led us to conclude that there is strong complexation Fe(III), Co(II) and Cu(II) with TDCR. These metal cations also produce quenching with red shifts in the emission spectra. The maximum quenching in emission intensity was observed in the case of Fe(III) and its binding constant was also found to be significantly higher than that of Co(II) and Cu(II). Quantum yield of metal complexes of Fe(III) was found to be lower in comparison with Co(II) and Cu(II) complexes. Stern Volmer analysis indicates that the mechanism of fluorescence quenching is either purely dynamic, or purely static. 相似文献
Employing electron paramagnetic resonance with diethyldithiocarbamate as a spin trap it was shown that after the transection
of the rat sciatic nerve the Cu(II) content increased in the proximal stump and did not change in the distal stump. No changes
of the Cu(II) content in dorsal root ganglia L4-L5 containing sensory neurons with their peripheral processes in the damaged
nerve were registered. 相似文献
Powder ESR spectra of the [Cu2(Asp)4](H2O)2 complex show the existence of Cu(II) acetate like dimers characterized by a strong antiferromagnetic exchange interaction (J=?288 cm?1). In pyridine-dimethylformamide solutions the monomeric species prevail. Two different monomeric species, the Cu(DMF)4 of planar-distorted tetrahedral (Td) symmetry and the Cu(Asp)2(DMF)2 with elongated tetrahedral-octahedral symmetry were evidenced in DMF solution adsorbed on NaY zeolite. In 40 % Py+60 % DMF solution two monomeric species were also identified. These are Cu(Asp)2(DMF)2 and Cu(Asp)2(Py)2, the last species having a CuN2O2 chromophore in atrans squareplanar arrangement. In pyridine Cu(II)-aspirinate solution only the Cu(Py)4 monomeric species of CuN4 chromophore was evidenced. 相似文献
Extensive study of composition, stability constants and optimum conditions of Fe(III), Nl (II) and Cu(II) complexes with four azo compounds based on 4 - amlnoantlpyrene are done. The coloured complexes formed, at the optimum. conditions mentioned, can be successfully used In the mlcrodetermlnation of metal Ions In synthetic solutions as well as In Incoloy 800 alloy. The method described Is rapid, sensitive, highly accurate and reproducable. 相似文献
Zn(II), Cd(II), Hg(II), Pb(II), Cu(I) and Ag(I) complexes of 5-benzylthio-1,2,4-triazole (BTT) have been prepared and characterised on the basis of analytical and IR data. Hg(II), Cd(II), Zn(II), and Pb(II) complexes are assigned tetrahedral structure with polymeric intermolecular linkages through S and N atoms while Ag(I) and Cu(I) are proposed to have polymeric linear structure 相似文献
Two new Cu(II) complexes with Picolinic acid and Tryptophan [Cu(II)(DPTR)(H2O)2](1:1) (1) and [Cu(II)(DPTR)(Phen)] (1:1:1) (2) were synthesized, characterized and studied their DNA binding, cleavage, docking and anti-cancer properties. The molecular modeling studies were carried out with energy minimized structures of metal complexes. CT-DNA binding studies revealed that the complexes bind through an intercalative mode and show good binding propensity. The docking study also confirms the intercalative mode of binding. The hydrolytic DNA cleavage activity of these complexes has been studied using gel electrophoresis. Complex 2 shows better efficiency than 1. Cell viability experiments indicated that the ligand, complexes show significant dose dependent cytotoxicity in selected cell lines.
Graphical Abstract Two new Cu(II) complexes with Picolinic acid and Tryptophan, [Cu(II)(DPTR)(H2O)2](1:1) (1) and [Cu(II)(DPTR)(Phen)] (1:1:1) (2) were synthesized, characterized and studied their DNA binding, cleavage, docking and anti-cancer properties.