Study on synthesis and electrochemical properties of novel ferrocene-based compounds and their applications in anion recognition

Two novel ferrocene-based compounds glycidyl ester of ferrocene carboxylate (GEFC) and 1,3-diferrocenecarboxylic acid diacylglycerol (DFCDG) were synthesized and characterized by ¹H NMR and mass spectrum. The influence of some factors, namely, solvent type, potential scan rate, electrolyte concentration and [Fe] unit concentration, on the electrochemical behaviors of two novel ferrocene-based compounds was investigated, and the mechanism of the electrode processes was studied. Finally, two compounds were applied to sense the H₂PO₄⁻ by cyclic voltammetry (CV) method and it was found that the DFCDG with a symmetric structure which was synthesized through ring opening reaction of ferrocene carboxylate and GEFC showed stronger interaction with the H₂PO₄⁻ than GEFC.     

Combined effects of sucrose and copper(II) ions on the growth and copper(II) bioaccumulation properties of Candida sp

A microbiological process using Candida sp was developed for the removal of copper(II) ions in the presence of molasses as nutrient. The combined effects of sucrose (in molasses) and copper(II) ions on the growth and copper(II) bioaccumulation properties of adapted Candida cells was tested under laboratory conditions as a function of initial pH and single‐sucrose and dual‐sucrose and copper(II) ion concentrations. The optimum pH value for maximum growth and metal ion accumulation was determined as 4.0 for the microorganism. At a constant copper(II) concentration, growth and copper(II) bioaccumulation increased with increasing concentrations of molasses sucrose up to 15 gdm⁻³. Although increased initial copper(II) concentration increased the copper(II) uptake capacity of the microorganism, inhibition by copper(II) ions of the growth of Candida sp was observed at all the concentrations of copper(II) at all the sucrose concentrations studied. The non‐competitive inhibition kinetics (assuming copper(II) ions as the toxic inhibitory component) were used to define the relationship between the specific growth rate and molasses sucrose and copper(II) concentrations and model parameters were determined by using experimental data. © 2000 Society of Chemical Industry     

Synthesis, crystal structure and electrochemical properties of a novel tetranuclear silver(I) cluster based on 1,1′-bis[(2-hydroxybenzylidene)thiocarbonohydrazono-1-ethyl] ferrocene (FcL)

A novel tetranuclear silver(I) heterocyclic cluster, which is of nano-hole structure, based on 1,1′-bis[(2-hydroxybenzylidene)thiocarbonohydrazono-1-ethyl] ferrocene (FcL) has been prepared and structurally characterized by single-crystal X-ray diffractions. In addition, its electrochemical properties are also discussed. The results confirm that the receptor FcL is responsive to Ag⁺.     

Study on the influence of anionic and cationic surfactant on Au-colloid modified electrode function by cyclic voltammetry and electrochemical impedance techniques

The influence of different surfactants on Au-colloid modified electrode function has been investigated by using cyclic voltammetry and electrochemical impedance techniques. Colloidal Au was self-assembled onto the gold electrode through the thiol-groups of 1,6-hexanedithiol (HDT) monolayer. It was found that some HDT molecules stood on the gold electrode and some molecules lay on the electrode by using the quartz crystal microbalance (QCM). A cathodic peak at about 0.486 V (vs. SCE) was observed at the bare gold electrode and the Au-colloid modified electrode. Cyclic voltammetry was used to investigate the influence of different surfactants on the cathodic peak of Au-colloid modified electrode. Electrochemical impedance technique was also used to study the electron transfer ability of the redox probe on Au-colloid modified electrode after being immersed in different surfactants. The results showed that anionic surfactant and cationic surfactant exhibit different behaviors, the reason of which was discussed.     

Adsorption of copper(II) and chromium(III) ions onto amidoximated cellulose

Chemical modification of cellulose powder is performed by successive reactions with acrylonitrile in an alkaline medium followed by aqueous hydroxylamine to prepare amidoximated cellulose. Due to complexation, the amidoxime groups immobilize heavy cations from buffered solutions at various pH values. The capacity of adsorption for Cu(II) and Cr(III) ions is related to the amount of amidoxime groups in the support and to the metal concentration of the polluted solution. The formation of a 1/1 complex is proved by the adsorption limit values. Desorption of the cations is possible by treatment with a stronger complexing agent such as ethylenediaminetetracetic acid. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1624–1631, 2000     

Comparison of 1-hydroxymethyl-3,5-dimethylpyrazole and 1-benzyl-2-hydroxymethylimidazole coordination properties towards copper(II)

Using 1-hydroxymethyl-3,5-dimethylpyrazole as the starting ligand and 2-propanol as the solvent and a molar ratio Cu:L, 1:4, a dinuclear Cu(II) complex has been obtained. The microanalytical data and the crystal structure reveal that the dicopper complex with two bridging methoxide groups contains the 3,5DMePz, 1-CH₂O-3,5DMePz and BF₄⁻ ligands which are received during the coordination process. The compound shows an antiferromagnetic intramolecular interaction between the Cu(II) ions.     

Adsorption of cadmium (II) and copper (II) ions from aqueous solution using chitosan composite

The binary chitosan/silk fibroin composite synthesized by reinforcement of silk fibroin fiber into the homogenous solution of chitosan in formic acid was used to investigate the adsorption of two metals of Cu(II) and Cd(II) ions in an aqueous solution. The binary composite was characterized by Fourier transform infrared and scanning electron microscopy. The optimum conditions for adsorption by using a batch method were evaluated by changing various parameters such as contact time, adsorbent dose, and pH of the solution. The experimental isotherm data were analyzed using the Freundlich and Langmuir equations, indicated to be well fitted to the Langmuir isotherm equation under the concentration range studied, by comparing the correlation co‐efficient. Adsorption kinetics data were tested using pseudo‐first‐order and pseudo‐second‐order models. Kinetics studies showed that the adsorption followed a pseudo‐second‐order reaction. Due to good performance and low cost, this binary chitosan/silk fibroin composite can be used as an adsorbent for removal of Cu(II) and Cd(II) from aqueous solutions. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

Synthesis,crystal structure and magnetic properties of a new cyanide-bridged mixed-valence copper(I)/copper(II) clathrate

A unique cyanide-bridge mixed-valence Cu^I/Cu^II clathrate of formula [Cu^I₂(CN)₃][{Cu^II(tren)}₂(μ-CN)](CF₃SO₃)₂ [tren = tris(2-aminoethyl)amine] containing cyanide-bridged [{Cu^II(tren)}₂(μ-CN)]^3 + binuclear cations stacked between anionic honeycomb layered copper(I) cyanide networks, was synthesized and structurally characterized by single crystal X-ray diffraction. Variable-temperature magnetic susceptibility studies showed that the cyanide bridge mediates a strong antiferromagnetic interaction between the copper(II) centers (J = − 160 cm^− 1, the spin Hamiltonian being defined as H = −J S_A⋅S_B).     

Mono- and multi-component biosorption of lead(II), cadmium(II), copper(II) and nickel(II) ions onto coco-peat biomass

The potential of using coco-peat biomass (CPB) has been assessed for the removal of Pb(II), Cd(II), Cu(II) and Ni(II) ions from single and quaternary solutions. According to Langmuir isotherm, the maximum biosorption capacity of CPB was 0.484, 0.151, 0.383 and 0.181 mmol/g for Pb(II), Cd(II), Cu(II) and Ni(II) ions, respectively. Scanning electron microscopy along with energy-dispersive X-ray spectroscopy and Fourier-transform IR spectroscopy confirmed changes in the biosorbent functionality after metal sorption. Through quaternary isotherm experiments, 16.1%, 48.2%, 32.3% and 46.5% decrease in experimental uptakes were observed for Pb(II), Cd(II), Cu(II) and Ni(II), respectively, in the presence of other metal ions.     

Gas sensing and electrochemical properties of rare earthferrite,LnFeO 3 (Ln = Nd,Sm)

In this paper, nanostructured perovskite-type LnFeO₃ (Ln = Nd, Sm) oxides were synthesized by thermal treatment method (TTM). Characterization analysis conducted by X-ray diffraction (XRD), scanning electron microscopy (SEM) and micro-Raman spectroscopy, have confirmed the perovskite structure of the synthesized nanomaterials. To study the effects of Nd and Sm lanthanides substitution at the A-site on the chemical sensing performance, conductometric and electrochemical sensors based on the synthesized LnFeO₃ samples were fabricated. LnFeO₃-based conductometric and electrochemical sensors were tested for acetone and dopamine sensing, respectively. The data revealed that Nd and Sm in the A-position lead to a significant influence in the gas sensing and electrochemical properties of perovskite LnFeO₃ samples. In particular, it has been demonstrated the good gas sensing characteristics of SmFeO₃ for acetone gas (Response = R/R₀ = 8.3–20 ppm acetone at 200 °C), whereas NdFeO₃ displayed better performance as electrode for the electrochemical detection of dopamine reaching a low detection limit (LOD) of 270 nM at S/N = 3. The electrical and electrochemical characteristics of the perovskite LnFeO₃ samples were discussed in detail with respect to their chemical composition and microstructure.     

Voltammetric behavior of Pd(II) and Ni(II) ions and electrodeposition of PdNi bimetal in N-butyl-N-methylpyrrolidinium dicyanamide ionic liquid

In this study, the voltammetric behavior of Pd(II), Ni(II), and mixtures of Pd(II) and Ni(II) was carried out in room-temperature N-butyl-N-methylpyrrolidinium dicyanamide ionic liquid (BMP-DCA IL). Electrodeposition of PdNi bimetal was achieved by controlled-potential electrolysis at iron wire electrodes from BMP-DCA containing various molar ratios of PdCl₂/NiCl₂. BMP-DCA shows good solubilities to PdCl₂ and NiCl₂, respectively, leading to the convenience for preparing the electrodepositing baths. By tuning the molar ratios of Pd(II)/Ni(II) in the electrodepositing baths and/or the applied potentials, PdNi coatings with various atomic contents of Pd could be obtained. Among these PdNi bimetallic coatings, the PdNi coatings with atomic ratios of ∼80/20 had the highest oxidation current in methanol oxidation reaction (MOR) in 1 M NaOH and exhibited the best poisoning tolerance. Powder X-ray diffraction analysis indicated that two separate metallic phases belonging to Pd and Ni existed in the PdNi coatings. The diffraction signal of Pd was very broad, indicating the tiny crystal size of Pd in the bimetal coatings. The scanning electron spectroscopic micrographs of PdNi coatings demonstrated that the Pd_∼80Ni_∼20 coatings had three-dimensional structures. This morphological characteristic implied that the composition and the surface morphology of the PdNi coatings equivalently contributed to the electrocatalytic activity toward MOR. The Pd_∼80Ni_∼20-coated iron-electrode (Fe/Pd_∼80Ni_∼20) was used to detect methanol and the linearity was observed in 3.53 μM to 758.88 μM using hydrodynamic chronoamperometry where a potential of −0.1 V (vs. Ag/AgCl) was applied.     

Kinetic analysis of the sorption of copper(II) ions on chitosan

The removal of copper ions from aqueous effluents by chitosan was studied in equilibrium and agitated batch contacting systems. The sorption capacities of chitosan for copper ions are 1.26 and 1.12 mmol g^?1 at pH 3.5 and 4.5, respectively. The equilibrium experimental data were best correlated by the Langmuir equation. The kinetics of sorption were studied at an initial solution pH of 4.5 and a chitosan particle size of 355–500 µm. The kinetics were analyzed using four models: the pseudo‐first‐order, pseudo‐second‐order, modified second‐order and Elovich equations. The rate parameters for the four models were determined and the Elovich equation provided the best correlation of the experimental kinetic data. Copyright © 2003 Society of Chemical Industry     

Synthesis,structure and properties of a new NH-1,2,3-triazole-based octanuclear copper(II) complex

An octanuclear copper complex, [Cu₈(L)₁₀(OH)₄Cl₂·(DMF)₂]·2DMF ( HL= 4-(2-bromophenyl)-2H-1,2,3-triazole) has been synthesized. Single crystal diffraction reveals that it crystallizes in the triclinic space group P − 1. The complex shows fluorescent quenching compared with the free ligand. The {Cu₈} displays overall strong antiferromagnetic (AF) coupling via hydroxyl groups, κ₂-N,N-trizaoles and κ₃-N,N,N-trizaoles, and the complex exhibits AF ordering under low temperature with T_N = 8.5 K.     

Copper (II) ions and copper nanoparticles‐loaded chemically modified cotton cellulose fibers with fair antibacterial properties

This work describes the release of copper(II) ions from cellulose fibers, which have been chemically modified by periodate‐induced oxidation of cellulose, followed by covalent attachment of biopolymer chitosan. The release of copper(II) ions has been investigated in physiological fluid (PF) and protein solution (PS) both at 37°C. Fibers have demonstrated excellent antibacterial activity against E. coli. Finally, their borohydride‐induced reduction has yielded copper nanoparticle‐loaded fibers, with average diameter of particles, nearly 28.94 nm. The formation of copper nanoparticles has been established by surface plasmon resonance and FTIR spectroscopy. These fibers also show fair biocidal action against E. coli. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Separation of gold(III) ions from copper(II) and zinc(II) ions using thiourea–formaldehyde or urea–formaldehyde chelating resins

Thiourea–formaldehyde (TF) and urea–formaldehyde (UF) chelating resins were synthesized and these resins were used in the separation of gold(III) ions from copper(II) and zinc(II) base metal ions. In the experimental studies, the effect of acidity on gold(III) uptake and gold(III) adsorption capacities by batch method, and loading and elution profiles of gold(III) ions, gold(III), copper(II), and zinc(II), dynamic adsorption capacities and the stability tests of TF and UF resins by column method were examined. By batch method, the optimum acidities were found as pH 2 and 0.5M HCl, and gold(III) adsorption capacities in the solutions including copper(II) and zinc(II) ions were obtained as 0.088 and 0.151 meq Au(III)/g for UF and TF resins, respectively. On the other hand, by column method, the dynamic adsorption capacities were calculated as 0.109 meq Au(III)/g with TF, 0.023 meq Au(III)/g with UF, 0.015 meq Cu(II)/g with TF, 0.0057 meq Cu(II)/g with UF, and under 6.1 × 10^?5 meq Zn(II)/g with TF or UF. TF resin was more effective in the separation and the concentration of gold(III) ions from copper(II) and zinc(II) ions than UF resin. It was seen that sulfur atoms contributed the gold(III) adsorption comparing with oxygen atoms. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Enhancing the ozonation of industrial wastewater with electrochemically generated copper(II) ions

This study evaluates the effect of adding electrochemical copper(II) ions into an ozonation process for treating industrial wastewater. Combining the processes resulted in a synergy that enhanced the reduction of physicochemical parameters (COD, TOC, color, turbidity, Z-Potential, and conductivity). In only 15 minutes the integrated process reduced the COD by 83%, TOC by 78 %, color by 93%, turbidity by 77%, and conductivity by 27% at relatively low current density (12.5 mA cm^?2). Thus, the combination of the electrochemical and ozonation processes noticeably improves wastewater quality, decreases the process time, and reduces the sludge production.     

Cationic conjugated polyelectrolyte-based fluorometric detection of copper(II) ions in aqueous solution

A series of water-soluble cationic polyfluorene copolymer containing 2,2′-bipyridine moieties (PFP-P_1-3) in the backbone were designed and synthesized as the fluorescent probes for Cu²⁺ ions. In the absence of the Cu²⁺ ion, the PFP-P₂ exhibits strong fluorescence emission in aqueous solution. Upon adding the Cu²⁺ ion, the PFP-P₂ coordinates to Cu²⁺ ions through weak N?Cu interactions, and its fluorescence is efficiently quenched by the Cu²⁺ ion with a Stern-Volmer constant (K_sv) of 1.44 × 10⁷ M⁻¹. The new method has high sensitivity with a detection limit of 20 nM. The minor interference from other heavy metal ions clearly shows that the PFP-P₂ can be used as the Cu²⁺ ion probe with good selectivity.     

In situ synthesis and dielectric properties of copper(II) and nickel(II) chiral Schiff base complexes

Two chiral Schiff base-containing complexes, [Cu(L¹)](ClO₄)₂·H₂O (1, L¹ = (S,S)-N1,N2-bis((1H-imidazol-4-yl)methylene)cyclohexane-1,2-diamine) and [Ni(L²)₂](ClO₄)₂ (2, L² = (S,S)-N1-((1H-imidazol-4-yl)methylene)cyclohexane-1,2-diamine) were synthesized from the reaction mixture of 1H-imidazole-4-carbaldehyde, (S,S)-1,2-diaminocyclohexane and Cu(ClO₄)₂·6H₂O or Ni(ClO₄)₂·6H₂O in methanol. Single-crystal X-ray diffraction analyses reveal that the in situ generated chiral Schiff base ligands L¹ and L² are bisubstituted and monosubstituted, respectively, corresponding to the different metal ions Cu^II and Ni^II. Variable-frequency and -temperature dielectric properties of 1 and 2 have been studied.     

Retention of cadmium ions from aqueous solutions by poly(ammonium acrylate) enhanced ultrafiltration

Cadmium removal from aqueous solution by polyelectrolyte enhanced ultrafiltration (PEUF) with relatively low transmembrane pressure was investigated at varying conditions of polyelectrolyte and cadmium concentrations, transmembrane pressure, ionic strength and pH. The poly(ammonium acrylate), with two average molecular weights (8000 and 15 000 Da) were used as polyelectrolyte. Flux declines during ultrafiltration of polyelectrolyte solutions. An effort has been made to evaluate these resistances independently at different operating conditions. The hydraulic membrane resistance is higher for processing solutions of PAmA₈ than solutions of PAmA₁₅. The study of ionic strength effect demonstrates that it decreases the retention of cadmium ions and increases the permeate flux. More than 99% of cadmium was retained for a NaNO₃ feed concentration less than 5 × 10⁻² mol L⁻¹. The pH effect study on the cadmium recovery revealed a maximum retention around 98% for pH 4.