Copper Cations Research Articles

Pengaruh Variasi Prekursor Terhadap Morfologi dan Aktivitas Antibakteri Nanopartikel Tembaga Menggunakan Reduktor Ekstrak Daun Gambir

Research on synthesis copper nanoparticles has been carried out by the bioreduction method with a green synthesis approach using extracts of gambir leaves (Uncaria gambir Roxb). Gambir leaf extract contains polyphenol compounds uses as a natural reducing agent to reduce copper cation from variations of prekursor (CuSO45.H2O, Cu(NO3)2.3H2O and CuCl2.2H2O). The formation of copper nanoparticles (CuNP) colloid is visually shown by color change from light brown to dark brown. Absorption peak in UV-Vis spectrophotometer analysis at 405 -427 nm which is a specific wavelength of copper nanoparticles base on phenomenon of Surface Plasmon Resonance (SPR). The X-Ray Diffraction (XRD) analysis showed formation of CuNP with a face centered cubic (fcc) crystal structure. The result of Transmission Electron Microscope show the synthesized CuNP was spherical with particle size diameter 15nm for CuSO4 prekursor, 25 nm for Cu(NO3) prekursor and 28 nm for CuCl2 prekursor. The size of nanoparticles influenced of type prekursor anions. The antibacterial activity of the synthesized nanoparticles was also tested using pathogenic bacteria Escherichia coli and Staphylococcus aureus. The results showed that copper nanoparticles were promising antibacterial agents. Antibacterial activity test on copper nanoparticles were found to have higher antibacterial activity against Gram positive bacteria S. aureus than Gram negatif E. coli.

Palladium-Catalyzed Electrooxidative Double C-H Arylation.

The electrochemical transition metal-catalyzed cross-dehydrogenative reaction has emerged as a promising platform to achieve a sustainable and atom-economic organic synthesis that avoids hazardous oxidants and minimizes undesired byproducts and circuitous functional group operations. However, a poor mechanistic understanding still prevents the widespread adoption of this strategy. In this regard, we herein present an electrochemical palladium-catalyzed oxidative coupling strategy to access biaryls in the absence of a stoichiometric chemical oxidant. The robust palladaelectrocatalysis considerably suppresses the occurrence of homocoupling and oxygenation, being compatible even with electron-deficient arenes. Late-stage functionalization and Boscalid precursor synthesis further highlighted the practical importance of our electrolysis. Remarkably, mechanistic studies including the evaluation of the reaction order of each component by variable time normalization analysis (VTNA) and initial rate analysis, H/D exchange experiment, kinetic isotope effect, and stoichiometric organometallic experiments provided strong support for the involvement of transmetalation between two organopalladium complexes in the turnover limiting step. Therefore, matching the concentrations or lifetimes of two distinct organopalladium intermediates is revealed to be a pivot to the success of electrooxidative catalysis. Moreover, the presence of cationic copper(II) seems to contribute to the stabilization of the palladium(0) catalyst instead of playing a role in the oxidation of the catalyst.

Hydrolysis of polyacrylamide in the presence of nano-sized copper particles

The process of hydrolysis of amide groups of polyacrylamide in the presence of a dispersion of nanosized copper particles obtained by the reduction of copper cations with sodium tetraborate was studied. Quantum chemical calculations showed an increase in the effective positive charge on the carbon atom in the amide group upon formation of a complex with copper. Calculation of the energy of interaction of polyacrylamide and polyacrylic acid macromolecule units with copper particles showed the possibility of replacing amide groups of the polymer that underwent hydrolysis from the surface of copper particles with amide groups that did not participate in the reaction. The degree of hydrolysis of polyacrylamide in the presence of copper particles was 89%, and in the absence of particles 22%.

Rice husk-based cellulose nanocrystal/poly(vinyl alcohol) composite film for the removal of Cu (II) cation from aqueous solution

Abstract In this study, a nanocomposite film comprising poly(vinyl alcohol) (PVA) and rice husk-derived cellulose nanocrystals (CNC) was introduced as a novel sorbent for removing copper (II) cations. First, CNC was isolated from neat rice husk, and then these particles with many ratios compared to PVA (2, 4, 6, and 10 wt.%) were added to the PVA solution to render the nanocomposite films. The obtained films were evaluated using scanning electron microscopy, Fourier-transform infrared spectroscopy, and water uptake tests. The optimal condition for the sorbent preparation was 10 wt.% of CNCs to PVA. The maximum ion adsorption percentage of the PVA/CNC 10 % film reached 55 % after 3 h exposure to 70 ppm Cu (II) ion solution at 25 °C. This research suggested a facile and feasible fabrication method of a nanocomposite film, considered a potential sorbent for the adsorption of copper (II) ions.

Enhancing Tank Leaching Efficiency through Electrokinetic Remediation: A Laboratory and Numerical Modeling Study

Electrokinetic remediation is a cost-effective and efficient method that utilizes electrical current to transport ions within the subsurface. This process aims to remediate soil contamination caused by industrial activities, which poses threats to wildlife, water quality, and air quality. To assess the impact of the electrokinetic process on tank leaching efficiency, two electrode configurations were tested: vertical and horizontal arrays. These tests considered variable electrode spacing and different voltages in the soil residue. Additionally, the movement of copper cations from the anode to the cathode under this process was investigated. Results show that the horizontal electrode array is more effective in transporting soil moisture because of its broader contact with the soil. After 20 days of using the electrokinetic method with vertical electrodes, the soil moisture content decreased by 12.28%; with horizontal electrodes, it dropped by 38.4%. Also, the concentration of copper in the soil near the cathode electrode increased from 0.54 to 0.77% after 20 days. The estimated copper ion content in the cathode area after 20 days was between 150 and 350 mol/m3, aligning closely with the measured value of 192.5 mol/m3. These results indicate that the electrokinetic process can significantly enhance copper recovery efficiency in tank leaching processes and curtail environmental side effects. Overall, this study provides valuable insights into the benefits of using the electrokinetic process to remediate leaching residue and improve the efficiency of industrial processes.

One-dimensional polymer of copper with salicylic acid and pyridine linkers: Synthesis, characterizations, solid state assembly investigation by hirshfeld surface analysis, and computational studies

A new one-dimensional polymeric copper complex [Cu(DNSA)py] with salicylic acid and pyridine was synthesized and characterized by many techniques, including FT-IR, UV–Visible, elemental, TGA/DSC, and single crystal XRD analysis. In the crystal structure, two 3,5-dinitrosalicylic ligands were chelated by the copper cation, in which one ligand was coordinated by the carbonyl O-atom and one of the carboxylate O-atoms, while another symmetry-related ligand was coordinated by the O-atoms of the carboxylate group to form distorted square pyramidal geometry. Thus, a one-dimensional polymer structure is formed, extending along the b-axis. The solid-state assembly was stabilized by various intermolecular interactions, as examined through Hirshfeld surface analysis. Voids analysis was carried out to predict the response of the crystal under external pressure. The most stable structure of the [Cu(DNSA)py] monomer resulted from density functional theory (DFT) using the B3LYP/def2-TZVPP. The 6–311G(d,p) level of theory demonstrated that the Cu atom adapts distorted square pyramidal geometry. The MEP surface and Mulliken charge distribution identified the Cu monomer atoms suitable for electrophilic and nucleophilic attacks. Frontier molecular orbital (FMO) analyses were conducted to anticipate the stability and chemical reactivity of the [Cu(DNSA)py] monomer and its ligand (DNSA). Furthermore, the quantum chemical descriptors of the title compound were obtained from EHOMO and ELUMO energy values.

Pincer Ligands as Multifunctional Agents for Alzheimer's Copper Dysregulation and Oxidative Stress: A Computational Evaluation.

Alzheimer's disease (AD) is the most common form of dementia worldwide, affecting millions of people around the globe. AD is characterized by different pathologies being beta-amyloid (Aβ) plaque formation, metal ion dysregulation, and oxidative stress (OS) central topics under investigation. Copper-Aβ complexes have been shown to induce catalytic hydrogen peroxide formation and increase OS in the brain leading to neuronal death. Pincer-type compounds are tridentate ligands that coordinate metals in a planar fashion whose properties can be tuned via group substitutions, giving rise to many possibilities in catalysis and drug discovery. In this work we evaluated the potential pharmaceutical activity of 26 pincer compounds in AD's copper ion-related oxidative stress framework. In this sense, four key aspects were considered: 1) Lipinski's rule of five, 2) blood-brain barrier permeation, 3) standard reduction potential (SRP) of the formed copper complexes, and 4) the ligand's affinity towards copper cations. The evaluation of these criteria was performed by means of bioinformatic tools and electronic structure calculations at the DFT level of theory. Our results suggest that two compounds from this set are potential antioxidant agents, whereas five of them are promissory distributor-like compounds in the context of AD.

Synthesis, crystal structure and thermal properties of poly[[μ-1,2-bis-(pyridin-4-yl)ethene-κ2N:N'-μ-bromido-copper(I)] 1,2-bis-(pyridin-4-yl)ethene 0.25-solvate

The reaction of copper(I) bromide with 1,2-bis-(pyridin-4-yl)ethene in aceto-nitrile leads to the formation of the title compound, {[CuBr(C12H10N2)]·0.25C12H10N2}n or CuBr(4-bpe)·0.25(4-bpe) [4-bpe = 1,2-bis-(pyridin-4-yl)ethene]. The asymmetric unit consists of one copper(I) cation and one bromide anion in general positions as well as two crystallographically independent half 4-bpe ligands and a quarter of a disordered 4-bpe solvate mol-ecule that are completed by centers of inversion. The copper(I) cations are tetra-hededrally coordinated as CuBr2N2 and linked by pairs of μ-1,1-bridging bromide anions into centrosymmetric dinuclear units that are further connected into layers by the 4-bpe coligands. Between the layers, inter-layer C-H⋯Br hydrogen bonding is observed. The layers are arranged in such a way that cavities are formed in which the disordered 4-bpe solvate mol-ecules are located. Powder X-ray (PXRD) investigations reveal that a pure sample has been obtained. Thermogravimetric (TG) and differential thermoanalysis (DTA) measurements show two mass losses that are accompanied by endothermic events in the DTA curve. The first mass loss correspond to the removal of 0.75 4-bpe mol-ecules, leading to the formation of (CuBr)2(4-bpe), already reported in the literature as proven by PXRD.

Determining gas-phase chelation of zinc, cadmium, and copper cations with HisHis dipeptide using action spectroscopy and theoretical calculations

Using light generated by an infrared free electron laser, action spectroscopy was performed on doubly charged complexes of the metalated dipeptide histidyl-histidine (HisHis). Metal cations used were zinc, cadmium, and copper. Molecular dynamics and quantum-chemical calculations were used to screen a large number of conformers, whose theoretical infrared spectra were compared to the recorded action spectra of these metalated complexes. The zinc and cadmium spectra display dominant features associated with an iminol binding motif of the HisHis ligand, where the metal ion coordinates with both pros (π) nitrogens of the imidazole sidechains, the terminal carbonyl oxygen, and the backbone nitrogen for which the hydrogen ordinarily bound here has migrated to a carbonyl. The copper complex was difficult to assign to a single species, because a few predicted bands are absent from the experimental spectrum. The theoretical single point energies were also calculated for all structures examined, and DFT methods were found to describe the ion conformer populations in the case of the zinc and cadmium chelates better than the MP2 prediction.

Mechanistic Insights into Copper(I) and Copper(II) Cation Exchange Reactions in CdSe Nanoplatelets

Mechanistic Insights into Copper(I) and Copper(II) Cation Exchange Reactions in CdSe Nanoplatelets

Characterization of Information-Transmitting Materials Produced in Ionic Liquid-based Neuromorphic Electrochemical Devices for Physical Reservoir Computing.

Device implementation of reservoir computing, which is expected to enable high-performance data processing in simple neural networks at a low computational cost, is an important technology to accelerate the use of artificial intelligence in the real-world edge computing domain. Here, we propose an ionic liquid-based physical reservoir device (IL-PRD), in which copper cations dissolved in an IL induce diverse electrochemical current responses. The origin of the electrochemical current from the IL-PRD was investigated spectroscopically in detail. After operating the device under various operating conditions, X-ray photoelectron spectroscopy of the IL-PRD revealed that electrochemical reactions involving Cu, Cu2O, Cu(OH)2, CuSx, and H2O occur at the Pt electrode/IL interface. These products are considered information transmission materials in IL-PRD similar to neurotransmitters in biological neurons. By introducing the Faradaic current components due to the electrochemical reactions of these materials into the output signal of IL-PRD, we succeeded in improving the time-series data processing performance of the nonlinear autoregressive moving average task. In addition, the information processing efficiency in machine learning to classify electrocardiogram signal waveforms was successfully improved by using the output current from IL-PRD. Optimizing the electrochemical reaction products of IL-PRD is expected to advance data processing technology in society.

Cu-Substituted Hydroxyapatite Powder: Mechanochemical Synthesis Using Different Copper Sources and Thermal Stability

In this paper, we present results of a study on the possibilities of the mechanochemical synthesis of copper-substituted hydroxyapatite with the replacement of calcium cations by copper cations. During the synthesis, various reagents—sources of copper cations—were used. It was found that the nature of the carrier of the doping cation plays an important role in the formation of the structure of Cu-substituted apatite. It was established that a single-phase material forms most efficiently when copper (II) phosphate is employed; however, even this reagent did not allow the introduction of a large amount of copper into the hydroxyapatite crystal lattice. Out of 10 calcium cations in the unit cell of hydroxyapatite, no more than two could be replaced by copper cations. A further increase in the copper concentration led to the formation of an amorphous product. The degree of copper substitution in hydroxyapatite increases as the oxidation state of copper increases. The thermal stability of the hydroxyapatite with the highest degree of substitution was studied. It was shown that the presence of copper cations significantly decreases the stability of hydroxyapatite. In a temperature range of 550–750 °C, it is gradually decomposed to form a mixture of rhombohedral Ca2.57Cu0.43(PO4)2 and CuO. The FTIR spectrum of Ca2.57Cu0.43(PO4)2, which is a copper-substituted β-Ca3(PO4)2, was first studied.

Preparation of amide oxime type surfactants and the chelation of copper and nickel cations

Preparation of amide oxime type surfactants and the chelation of copper and nickel cations

Optimization, Kinetics, and Isotherm Studies of Methyl Thioninium Chloride Removal from Simulated Solutions Using Chitosan Derivatives.

Methylene blue (MB) dye or methyl thioninium chloride is one of the hazardous cationic dyes that are discharged into the textile effluent causing a highly negative environmental impact. The present work targets the investigation of the adsorption performance of some chitosan-modified products toward the MB dye from simulated solutions. The claimed chitosan derivatives were prepared, characterized, and applied for the removal of lead and copper cations from an aqueous medium in a previous work. These include: N,O-carboxymethyl chitosan (N,O-CM/Cs), chitosan grafted with glutaraldehyde (Cs/GA), chitosan cross-linked with GA/epichlorohydrin (Cs/GA/ECH), and chitosan cross-linked with glutaraldehyde/methylene bis(acrylamide) (Cs/GA/MBA). The modified chitosan derivatives in this study displayed outstanding mechanical qualities, exceptional reusability, and a significant amount of adsorption capacity. The ability of prepared Cs derivatives to eradicate MB was as follows: N,O-CM/Cs (95.1 mg/g) < Cs/GA (120.1 mg/g) < Cs/GA/ECH (220.1 mg/g) < Cs/GA/MBA (270.0 mg/g). The swelling performance of the prepared sorbents was verified under different experimental conditions, and the data revealed that the maximum swelling was attained at pH = 9, temperature 55 °C, and after 24 h. The produced Cs derivatives showed exceptional reusability by maintaining higher adsorption effectiveness throughout five cycles. The MB dye was adsorbed onto the modified derivatives according to pseudo-second-order kinetics and the Langmuir model. Moreover, the adsorption process was monitored via atomic force microscopy to verify the differences between the dye-free and dye-loaded adsorbents.

Insights into Molecules of Natural Organic Matter Binding with a Copper(II) Cation: Interpretation Based on FT-ICR-MS and Differential UV–Vis Absorbance Spectra

Insights into Molecules of Natural Organic Matter Binding with a Copper(II) Cation: Interpretation Based on FT-ICR-MS and Differential UV–Vis Absorbance Spectra

Synthesis and study of composite materials based on apple pectin and copper cations

The paper presents the results of synthesis the metal-composite materials based on apple pectin and divalent metal cations - Cu2+; determining the degree of esterification and the content of free carboxyl groups of the native pectin by acid-base titration, determining the degree of inclusion of the specified cation in the polysaccharide macromolecule and studying by IR spectroscopy and fungicidal activity of native pectin and copper complexes against Penicillum sp According to the results of titration, it was found that apple pectin has a high degree of esterification (DE = 50.7%) and a low content of carboxyl groups (Kc = 2.79%), which suggests its low gelling activity. It was found that the increase in salt concentration is above 0.005 g-eq/l. leads to a decrease in the proportion of the resulting water-soluble complex. The optimal concentration of CuSO4 5H2O, at which the largest mass of the water-soluble complex is formed, is 0.005 g-eq/l. According to IR spectroscopy, the degree of substitution of sodium cations for copper cations was calculated, which amounted to 18%. It was shown that the native apple pectin does not have fungicidal activity, while the copper complex based on it is able to suppress the growth of the culture already under the action of 10 µl of the substance, and with an increase in volume to 50 µl, an even more active fungicidal activity of the copper complex appears.

Electrodialysis for Removal of Impurities in Silver Electrowinning

In this work, we investigate the potential of electrodialysis to separate copper from silver electrowinning solution. We further explore and discuss optimization of the electrodialysis process design.Ag is in a high global demand, driven mainly by its use in electronics, jewelry and as investment. The recycling potential for Ag is large and will increase in the coming years due to Ag usage in solar panels. One route of recycling Ag from End-of-life products is batch-electrowinning. In preparation, the products are melted and reshaped into scrape plates which are anodically dissolved in nitric acid solution. Typically, silver is found in alloys with less noble metals like copper, zinc, and iron. While silver is deposited on the stainless-steel cathode surface, the impurities accumulate in the electrolyte. To maintain a high purity of the recycled silver, the contaminated nitric acid solution must be replaced regularly. We investigate the potential of implementing a continues electrodialysis stage parallel to the electrowinning bath to remove copper and other divalent cations from the solution.In electrodialysis, anion- and cations-exchange membranes are stacked alternatingly between two electrodes. When a current is drawn, the cations move towards the cathode, passing the cation-exchange membrane and vice versa for the anions. Since the membranes are selective for either anions or cations, they strongly retard the passage of the opposite ion. Therefore, cations and anions are accumulated in every second compartment, while every other chamber is desalinated. By using monovalent-selective ion-exchange membranes, separation between monovalent (f. ex., Ag+) and multivalent ions (f. ex., Cu2+, Zn2+, Fe2+, Fe3+) can be achieved [1].If the concentration of impurities can be held at a constant level, the nitric acid solution can be recycled continuously rather than replaced as a batch. The only consumable required by the process is electricity. We evaluate the viability of the process and investigate the influence of pH on the process efficiency.We determined the optimal operating current for separating Cu2+ from Ag+ in an equimolar concentration of 10 mM by doing amperodynamic sweeps and recording current-voltage curves. We then tested the desalination performance of an electrodialysis stack with different commercially available anion-/cation-exchange membrane pairs. The single membrane area was 36 cm2, and 9 membranes were used in total (five anion-exchange membranes and four monovalent-selective cation-exchange membranes). The Cu2+ and Ag+ concentrations in the diluate and concentrate compartments were determined by atomic mass spectrometry, and the membranes were analyzed with scanning electrode microscopy to detect adsorbed silver. Since scaling and fouling are dominant drawbacks in industrial applications of electrodialysis, we studied the influence of pH on the adsorption of silver in the membrane.Commercial monovalent-selective cation-exchange membranes by Neosepta showed high selectivity for silver over copper. The limiting current density was 10.4 A/m2 for neutral 10 mM AgNO3 solution at a flow rate of 100 mL/min and increased by almost 10 times when we adjusted the pH to 1 using nitric acid. In neutral solution, silver was recovered to almost 100 % after two hours of electrodialysis at 10 mA, while copper leakage was 7.5 %. At pH 1, silver recovery and copper leakage were 83 % and 9 %, respectively, after two hours electrodialysis at 100 mA. Consequently, the percentage silver adsorbed in the membranes were close to 0 % in neutral solution and 17 % at pH 1. The work input was significantly higher at pH 1 due to electric current consumed by mass transport of protons. As a next step, we investigate the long-term effect on the membranes with regards to Ag and Cu adsorption, which could be stabilizing at a certain concentration of Ag and Cu or increasing over time.We conclude that electrodialysis is a promising technology for removal of impurities in Ag electrowinning from End-of-life products, justifying large room for future research on development of membranes and operational design.[1] Zimmermann, P., Tekinalp, Ö., Deng, L., Forsberg, K., Wilhelmsen, Ø., Burheim, O. (2020). Electrodialysis in Hydrometallurgical Processes. In: Azimi, G., Forsberg, K., Ouchi, T., Kim, H., Alam, S., Baba, A. (eds) Rare Metal Technology 2020. The Minerals, Metals & Materials Series. Springer, Cham.

Rhodamine 6G based molecular ion-active switches of optical and fluorescent properties

A series of rhodamine 6G derivatives with o -hydroxyarylime substituents was synthesized. The obtained compounds in acetonitrile are capable of H+ induced transformation of the spirolactam form into open form. The process is accompanied by the formation of new long-wave absorption maxima at 527-529 nm and fluorescence bands at 557-560 nm. The compound containing 2-hydroxy-4-dimethylaminophenyl substituent in the presence of Zn2+ cations displays switching of emission at 429 nm. This fluorescence is quenched selectively by the CN- anion. Copper(II) cations cause the transformation of the spirostructure of rhodamine with a 2-hydroxy-3- tert -butylbenzofuran group into an open form. Isomerization occurs with a chromogenic naked-eye effect - a change in the color of the solution from pale yellow to pink and the appearance of fluorescence at 556 nm. The observed ion-induced spectral transformations can be used in design of optical and fluorescent chemosensors.

Antibacterial Cu or Zn-MOFs Based on the 1,3,5-Tris-(styryl)benzene Tricarboxylate.

Metal-organic frameworks (MOFs) are highly versatile materials. Here, two novel MOFs, branded as IEF-23 and IEF-24 and based on an antibacterial tricarboxylate linker and zinc or copper cations, and holding antibacterial properties, are presented. The materials were synthesized by the solvothermal route and fully characterized. The antibacterial activity of IEF-23 and IEF-24 was investigated against Staphylococcus epidermidis and Escherichia coli via the agar diffusion method. These bacteria are some of the most broadly propagated pathogens and are more prone to the development of antibacterial resistance. As such, they represent an archetype to evaluate the efficiency of novel antibacterial treatments. MOFs were active against both strains, exhibiting higher activity against Staphylococcus epidermidis. Thus, the potential of the developed MOFs as antibacterial agents was proved.

Mesoporous silicas of MCM-48 and MCM-41 types doped with copper by modified template ion-exchange method as effective catalysts for low-temperature reduction of nitrogen oxide with ammonia

Mesoporous silica materials of MCM-48 and MCM-41 types were synthetized by surfactant directed methods and modified with copper by template ion-exchange (TIE) protocol and its extended version including post-treatment of modified silicas with ammonia solution. Obtained samples were characterized with respect to their textural parameters (low-temperature N2 sorption), porous structure, chemical composition, surface acidity (NH3-TPD), form and aggregation of deposited copper species (UV–vis-DRS) as well as their reducibility (H2-TPR). It was shown that application of TIE method resulted in deposition of copper into MCM-48 in more dispersed forms comparing to MCM-41. Both, in the case of MCM-41 and MCM-48, treatment of the samples with ammonia directly after copper introduction resulted in deposition mainly monomeric copper cations. The catalysts containing such dispersed copper species were more active in the low-temperature NH3-SCR process. The NO conversion above 90% with selectivity to N2 above 97% was obtained in the temperature range of 225–325 °C. CuO aggregates, deposited on mesoporous silicas, were found to be active in the side process of direct ammonia oxidation at higher temperatures.