Water-soluble Copper Research Articles

Investigation on water soluble copper(II) mono-anionic glutamate complexes with planar aromatic ligands: synthesis, crystal structures, biomacromolecular interactions and radical scavenging activities

Two water soluble copper(II) mono-anionic glutamatecomplexes -[Cu(phen)(glu)(H2O)]NO3·H2O (1) and [Cu(py-phen)(glu)(H2O)]NO3·H2O (2) - (phen: 1,10-phenanthroline, py-phen: pyrazino[2,3-f][1,10]phenanthroline, glu: glutamic acid), have been synthesized and characterized by CHN analysis, ESI-MS, FTIR and single-crystal X-ray diffraction techniques. Interaction of the complex with biomacromolecules {calf thymus DNA (CT-DNA) and bovine serum albumin (BSA)} has been investigated by electronic absorption and fluorescence spectroscopy methods. The experimental outcomes displays that the complexes 1 and 2 bind to CT-DNA by means of a moderate intercalation mode. Furthermore, the fluorescence quenching mechanism between BSA and the complexes 1 and 2 is a static quenching process. The Stern-Volmer constants, binding constants, binding sites and the corresponding thermodynamic parameters (ΔG, ΔH, ΔS) of BSA+ the complexes 1 and 2 systems were determined at different temperatures. The binding distance between BSA and the complexes 1 and 2 was calculated according to Förster non-radiation energy transfer theory (FRET). The effect of the complexes 1 and 2 on the conformation of BSA was also examined using synchronous, two dimensional (2D) and three dimensional (3D) fluorescence spectroscopy. Radical scavenging activity of the complexes 1 and 2 was determined in terms of IC50, using the DPPH and H2O2 method. In biomacromolecules interactions and radical activity studies, the complexes 1 and 2 were found to give good results.

Highly efficient electrocatalytic hydrogen evolution from neutral aqueous solution by water soluble copper (II) porphyrin

A water soluble Cu (II) porphyrin bearing para-sulfonic group at mesophenyl rings is reported as molecular electrocatalyst for H2 generation from neutral aqueous solution. Electrocatalysis study in buffer solution of pH 7.2 showed that the complex is highly active, efficient and stable toward H2 evolution. It features an observed rate constant (kobs) of 8.6 × 103 s−1 and Faradaic efficiency of 98.3% at an overpotential of 470 mV. The role of functional group on catalytic activity is also investigated by conducting heterogeneous catalysis involving Cu-porphyrin with (CuTPPS) and without (CuTPP) para-sulfonic groups. Hence differential pulse voltammetry, controlled-potential electrolysis and electrochemical impedance spectroscopic measurements show that, CuTPPS-modified electrode perform much better than that of CuTPP-modified. This may be attributed to an increase in the amount of catalyst at the vicinity of electrode surface because of the ability of para-sulfonic functional group to anchor to electrode surface. Moreover, its electron withdrawing behaviour and ability to donate proton to the solution in turn thermodynamically favour H2 evolution.

A highly sensitive chemiluminescence assay for diniconazole by using CuInS2 quantum dots

We demonstrate here the first use of water-soluble copper indium sulfide quantum dots (CuInS2 QDs) as the chemiluminescence (CL) reagent and its application to the highly sensitive detection of diniconazole. We utilized a hydrothermal method for synthesis of mercaptopropionic acid-capped CuInS2 QDs, which were characterized by TEM image, EDS, and XRD pattern. The performance of these QDs as the CL reagent was investigated by using several oxidizing agents and found that acidic potassium permanganate (KMnO4) gave the highest CL signal. CuInS2 QDs/KMnO4 as a novel CL probe was then used for assay of diniconazole based on its unique enhancing effect. In the optimum settings, a linear calibration plot was obtained for diniconazole in the concentration range of 4.0 × 10−9 mol L−1–1.5 × 10−6 mol L−1, with a limit of detection of 1.0 × 10−9 mol L−1. The study of interferences and recoveries confirmed the suitability of the method for assay of environmental water samples.

Hydrothermal Synthesis of Aqueous-Soluble Copper Indium Sulfide Nanocrystals and Their Use in Quantum Dot Sensitized Solar Cells.

A facile hydrothermal method to synthesize water-soluble copper indium sulfide (CIS) nanocrystals (NCs) at 150 °C is presented. The obtained samples exhibited three distinct photoluminescence peaks in the red, green and blue spectral regions, corresponding to three size fractions, which could be separated by means of size-selective precipitation. While the red and green emitting fractions consist of 4.5 and 2.5 nm CIS NCs, the blue fraction was identified as in situ formed carbon nanodots showing excitation wavelength dependent emission. When used as light absorbers in quantum dot sensitized solar cells, the individual green and red fractions yielded power conversion efficiencies of 2.9% and 2.6%, respectively. With the unfractionated samples, the efficiency values approaching 5% were obtained. This improvement was mainly due to a significantly enhanced photocurrent arising from complementary panchromatic absorption.

Water-soluble copper(II) complexes with 4,5-dichloro-isothiazole-3-carboxylic acid and heterocyclic N-donor ligands: Synthesis, crystal structures, cytotoxicity, and DNA binding study

Mixed-ligand copper(II) complexes based on 1,10-phenanthroline and related compounds are of interest to scientists due to their promising anticancer properties. In this study, four new water-soluble copper(II) complexes [Cu(dmbipy)L2], [Cu(phen)(H2O)L2], [Cu(dmphen)L2] and [Cu2(bipy)2L4], where HL – 4,5-dichloro-isothiazole-3-carboxylic acid, bipy – 2,2′-bipyridine, dmbipy – 2,2′-bi-4-picoline, phen – 1,10-phenanthroline, dmphen – 4,7-dimethyl-1,10-phenanthroline are reported. All complexes have been characterized by elemental and powder X-ray diffraction analysis, EPR and IR-spectroscopy. Molecular structures of the reported complexes have been determined by single crystal X–ray diffraction. Copper(II) ion, HL and heterocyclic N-donor ligands have been found to form 1:2:1 complexes that possess square bipyramid or square pyramidal geometry. The UV–vis spectroscopy and mass spectrometry have been applied to show the behavior of the compounds in solution. All complexes have been screened in vitro for their cytotoxic activity against Hep-2 and MCF-7 cell lines. They exhibit significant dose-dependent cytotoxic effect and [Cu(dmphen)L2] is found to be the most cytotoxic (IC50 = 0.97 ± 0.03 µM when compared to IC50 = 9.2 ± 0.5 µM for control, cisplatin – Hep-2 cell line). The investigation of DNA binding ability by UV–vis titration technique indicates that complexes obtained exhibit moderate binding affinity toward calf thymus DNA. Effect of [Cu(dmbipy)L2] and [Cu(dmphen)L2] on activity of drug-metabolizing enzymes cytochromes P450 has also been investigated. The addition of complexes to the hepatic microsomes of 3-MC or PB-treated rat, lead to a dose-dependent decrease of CYP’s activities. The data obtained indicate that [Cu(dmphen)L2] and [Cu(phen)(H2O)L2] can be potential anticancer agents.

Molecular mechanisms of apoptosis induction in K562 and KG1a leukemia cells by a water-soluble copper(II) thiosemicarbazone complex

Thiosemicarbazones (TSCs) and their metal complexes exhibit pronounced and selective cytotoxic potential against a broad span of cancers. Here, we assessed the anti-cancer activity of a water-soluble copper(II) complex of thiosemicarbazone (Cu-TSC) against two cancer cell lines of human leukemia. Our analysis revealed that Cu-TSC treatment results in a time and dose-dependent growth inhibition in K562 and KG1a cells while sparing normal human fibroblast (HFF2) cells. The IC50 values for the Cu-TSC treatment were measured to be 21.7 ± 1.5µM and 50.25 ± 2.5µM for K562 and KG1a cells, respectively. Cell cycle analysis indicated that Cu-TSC induces the accumulation of cells in the sub-G1 fraction as well as the reversible arrest in G0/G1 and G2/M phases in K562 and KG1a cells, respectively. Furthermore, the occurrence of apoptosis as the prime mode of cell death was verified through apoptotic body formation, phosphatidylserine externalization, and caspase-3 activation. Additionally, the real-time quantitative PCR analysis revealed that Cu-TSC triggers apoptosis in both cell lines via the upregulation of caspases-8, -9, and the changing of Bax/Bcl2 ratio. Finally, flow cytometric analysis confirmed that Cu-TSC treatment causes the enhancement of reactive oxygen species formation in both K562 and KG1a cells. Altogether, these findings suggest that Cu-TSC is a promising inducer of apoptosis in leukemia cells and carries potential as an anti-cancer compound.

Green Organic Solvent-Free Oxidation of Alkylarenes with tert-Butyl Hydroperoxide Catalyzed by Water-Soluble Copper Complex

AbstractDifferent benzylic compounds were efficiently oxidized to the corresponding ketones with aqueous 70% tert-butyl hydroperoxide (TBHP) and the catalytic system composed of CuCl2.2H2O and 2,2’-biquinoline-4,4’-dicarboxylic acid dipotassium salt (BQC). The catalytic system CuCl2/BQC/TBHP allows obtaining high yields at room temperature under organic solvent-free conditions. The interest of this system lies in its cost effectiveness and its benign nature towards the environment. Benzylic tertbutylperoxy ethers and benzylic alcohols were observed and suggested as the reaction intermediates. Analysis of organic products by atomic absorption did not show any contamination with copper metal. In terms of efficiency, CuCl2/BQC system is comparable or superior to the most of the catalytic systems described in the literature and which are based on toxic organic solvent.

Aluminum-Enhanced Fluorescence of Cu8 Nanoclusters: An Effective Method for Sensitive Detection of Fluoride in Aqueous and Bioimaging.

Here, we report glutathione-protected water-soluble copper nanoclusters (Cu8 NCs) with excellent properties of high stability, large Stokes shift, and low toxicity. The molecular formula and structure of the Cu8 NCs were confirmed through good agreement between spectroscopic results and theoretical calculations. The origin of optical properties and chemical stability of the Cu8 NCs was determined through natural bond orbital analysis combined with time-dependent density functional theory calculations. It was found that the fluorescence emission and quantum yields of Cu8 NCs could be effectively enhanced by aluminum(III) ions (Al3+) through the aggregation-induced enhanced emission mechanism. On the basis of the strong reaction of Al3+ with F-, the enhanced fluorescence of the obtained Cu8 NC-Al3+ ensemble could be selectively turned off by fluoride ions (F-), achieving highly sensitive detection of F- in aqueous with a detection limit of 0.16 μM. Also, the fluorescence of Cu8 NC-Al3+ ensemble quenched by F- could be enhanced again upon binding additional Al3+. In addition, the proposed Cu8 NC-Al3+ ensemble with enhanced fluorescence was used for bioimaging in vitro and in vivo. These results indicated that Cu8 NCs are promising materials for sequential sensing and bioimaging in the future.

Synthesis, Structural, and Cytotoxic Properties of New Water-Soluble Copper(II) Complexes based on 2,9-Dimethyl-1,10-Phenanthroline and Their One Derivative Containing 1,3,5-Triaza-7-Phosphaadamantane-7-Oxide.

A series of water-soluble copper(II) complexes based on 2,9-dimethyl-1,10-phenanthroline (dmphen) and mixed-ligands, containing PTA=O (1,3,5-triaza-7-phosphaadamantane-7-oxide) have been synthesized and fully characterized. Two types of complexes have been obtained, monocationic [Cu(NO3)(O-PTA=O)(dmphen)][PF6] (1), [Cu(Cl)(dmphen)2][PF6] (2), and neutral [Cu(NO3)2(dmphen)] (3). The solid-state structures of all complexes have been determined by single-crystal X-ray diffraction. Magnetic studies for the complex 1–3 indicated a very weak antiferromagnetic interaction between copper(II) ions in crystal lattice. Complexes were successfully evaluated for their cytotoxic activities on the normal human dermal fibroblast (NHDF) cell line and the antitumor activity using the human lung carcinoma (A549), epithelioid cervix carcinoma (HeLa), colon (LoVo), and breast adenocarcinoma (MCF-7) cell lines. Complexes 1 and 3 revealed lower toxicity to NHDF than A549 and HeLa cells, meanwhile compound 2 appeared to be more toxic to NHDF cell line in comparison to all cancer lines. Additionally, interactions between the complexes and human apo-transferrin (apo-Tf) using fluorescence and circular dichroism (CD) spectroscopy were also investigated. All compounds interacted with apo-transferrin, causing same changes of the protein conformation. Electrostatic interactions dominate in the 1/2 – apo- Tf systems and hydrophobic and ionic interactions in the case of 3.

Synthesis and spectral characterizations of water soluble Cu(ii) complexes containing N-heterocyclic chelates: cell-proliferation, antioxidant and nucleic acid/serum albumin interactions

Water soluble N-heterocyclic copper(ii) complexes were synthesized, characterized and studied their DNA/protein binding interactions, antioxidation and antiproliferative potentials. The complex 4 found to be better than other complexes.

A polyamine dendritic polymer–copper complex: a reusable catalyst for the additive-free amination of aryl bromides, and iodides

Additive-free synthesis of aryl amines from aryl halides using a reusable water-soluble porphyrin-cored amine-functionalized dendritic polymer copper complex (PPECH–Amine–Cu) catalyst in aqueous media.

Lysozyme coated copper nanoclusters for green fluorescence and their utility in cell imaging

Green fluorescent, pH dependent and water soluble copper nanoclusters (3–5 nm) were synthesized by stabilizing with lysozyme and these were demonstrated for imaging in both healthy and cancer cell lines as an alternate to green fluorescent protein.

The influence of electrolyte usage on the growth of nanostructured anodic films on copper in sodium carbonate aqueous solution

Anodization of copper was performed in 0.1 M K2CO3 at 25 and 50 V. In order to study the influence of the electrolyte usage, samples were anodized in fresh electrolyte and electrolyte that was applied for anodizing for 2, 4 and 6 h. It was found that during anodization, the current oscillates with time. It means that there are cycles of adsorptions and delaminations of the anodic film of the samples. Moreover, the longer the electrolyte is used, the faster steady state of current densities without oscillations is achieved and the greater the current densities are. According to the Pourbaix diagram, the greater concentration of the water soluble copper species, the greater the CuO passivity field, thus the anodic oxides are formed much easier. For this reason, X-ray diffraction patterns revealed increasing content of tenorite phase (CuO) over cuprite (Cu2O) when the electrolyte is being re-used. For electrolytes pre-used for 6 h, no cuprite was found in the samples. Moreover, the longer the pre-usage of the electrolyte, the smaller the diameter of the grown nanowires. For anodizing performed at 25 V, nanowire diameter decreases from 55 ± 12 nm to 36 ± 7 nm (electrolyte pre-used for 6 h) in a linear manner.

Photochemical CO2 Reduction Driven by Water-Soluble Copper(I) Photosensitizer with the Catalysis Accelerated by Multi-Electron Chargeable Cobalt Porphyrin

Without using precious elements, a highly efficient and selective molecular-based photocatalytic system for CO2-to-CO conversion in fully aqueous media has been developed. Our copper(I)-based water...

In vitro cytotoxicity of new water soluble copper(II) metallates containing 7-hydroxy-4-oxo-4H-chromene thiosemicarbazones

7-Hydroxy-4-oxo-4H-chromene Schiff bases and their corresponding water soluble copper(II) complexes were synthesized and characterized by various spectral techniques. The structural confirmation of the complexes 2 and 3 has been provided by X-ray crystallographic analysis. The binding affinities of the ligands and complexes with Calf Thymus DNA (CT-DNA) and proteins (Bovine Serum Albumin (BSA) and Human Serum Albumin (HSA)) were studied by using absorption and emission titration methods. An intercalative mode of binding with CT-DNA and a static quenching mechanism with albumin (BSA and HSA) was confirmed from the obtained results. The efficiency of the compounds in inhibiting the microbial growth was tested against various pathogenic bacteria Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pneumoniae and Acinetobacter baumannii by using Gentamicin as standard and fungi Candida albicans, Aspergillus niger, Trichophyton rubrum, Candida tropicalis and Aspergillus fumigatus by using ketoconazole as standard and a significant activity has been found for the complexes. The anticancer potential of the ligands and complexes were tested against A549 and MCF-7 cells by MTT assay using cisplatin as a standard. The complexes 1–4 showed better cytotoxic profile than cisplatin, when incubated for a period of 48 h and 72 h. The results of all the biological analyses indicated the higher activity of the complexes over the ligands. Out of the complexes, complex 3 with the more electron donating ethyl group exhibited the higher activity.

Synthesis of fluorescent pink emitting copper nanoparticles and sensitive detection of α-naphthaleneacetic acid.

Detecting NAA in food has drawn intense attention as it has imposed significant threat to people's health and the growth of food industry. Over the past few years, great importance has been attached to the application of copper nanomaterials as fluorescent probe to food and environmental detection. Here, the simple, rapid, cost effective and water soluble fluorescent copper nanoparticles were synthesized with chemical reduction sonochemical assisted method for highly selective and sensitive detection of α-naphthaleneacetic acid (NAA) by using 2-mercaptobenzothiazole (MBT) as a protecting agent and polyvinylpyrrolidone (PVP) as a stabilizing agent (MBT-PVP CuNPs). The resultant CuNPs has a spherical shape with an average diameter of 10-15 nm and strong fluorescent pink emission characteristic peak at 580 nm upon 334 nm excitation. Interestingly, upon the addition of NAA, the fluorescence of MBT-PVP CuNPs can be effectively quenched for the reason that NAA could interact with MBT via hydrogen bonding and conform copper-NAA clathrate with Cu+ via coordination bond, which shows a good linearity in the range of NAA from 0.5 to 50 μM and with a detection limit of 9.6 nM. Moreover, the prepared probe has good selectivity for NAA detection over other co-existing molecules. It is worth mentioning that this method has been successfully applied to authentic comestible sample analysis and obtained satisfying and promising results, which indicates that this strategy is likely to have a promising application potential for NAA detection in the field of food safety.

Antiproliferative activity of copper(II) glutamine complexes with N,N-donor ligands: Synthesis, characterization, potentiometric studies and DNA/BSA interactions

New water soluble copper(II) complexes, - [Cu(phen)(gln)(H2O)]NO3·H2O (1) and [Cu(dmphen)(gln)(H2O)]ClO4 (2) - (phen: 1,10-phenanthroline, dmphen: 4,7-dimethyl-1,10-phenanthroline, gln: l-glutamine), have been synthesized and characterized by CHN analysis, ATR-FT-MIR, ESI-MS and single-crystal X-ray diffraction techniques. Binary and ternary complexes of copper(II) with the selected ligands have been investigated using potentiometric methods in 0.1 M KCl aqueous ionic media at 298.2 K. The protonation constants of the selected ligands and the stability constants of the complexes 1 and 2 have been calculated from the potentiometric data using the “BEST” software package and the potentiometric results have been analyzed using the “SPE” software package. The binding interaction of the complexes with calf thymus DNA (CT-DNA) was investigated by electronic absorption and emission spectroscopic methods revealed that the complexes could interact with CT-DNA via a moderate intercalation mode. The fluorescence quenching mechanism of bovine serum albumin (BSA) by the complexes was analyzed and the binding constant has been calculated. In vitro antiproliferative effect of the complexes was examined on human tumor cell lines (Caco-2, A549 and MCF-7) and healthy cells (BEAS-2B). The complex 2 showed remarkable antiproliferative activity compared to the complex 1 and cisplatin.

Novel binuclear and trinuclear metal (II) complexes: DNA interactions and in vitro anticancer activity through apoptosis

A water soluble trinuclear copper(II) complex and a binuclear cobalt(II) complex, namely Cu3(ppbm)2(SO4)3 (1) and Co2(ppbm)2(NO3)4 (2) (ppbm = 2-(pyridin-2-yl)-1-(pyridin-3-ylmethyl)- 1H-benzo[d]imidazole), have been successfully synthesized and characterized by elemental analysis, IR Spectroscopy, electrospray ionization mass spectra (ESI-MS). The interaction of the new complexes with DNA has been explored using spectroscopy methods, indicating that the complexes 1 and 2 bind to DNA via noncovalent interactions. DNA cleavage experiment suggested that the complex 1 exhibits efficient DNA cleavage activities in the presence of ascorbate (Asc), hydrogen peroxide may serve as the major cleavage active species. The cytotoxicity assay showed that complex 1 exhibited significant inhibitory activity toward the proliferation of several tumor cell lines, with a lower IC50 value than cisplatin and complex 2, indicating that it had the potential to act as effective anticancer agent. The morphological staining assays showed that 1 apparently induced the TFK-1 cells apoptosis. Besides, cellular uptake experiment on TFK-1 cells revealed that complex 1 accumulates primarily inside the nucleus. The apoptosis was attributable to the metal-assisted generation of reactive oxygen species (ROS).

Neutralization of sewage sediments by utilization of steel industry wastes

Utilization of sewage sediments as a soil modifier is one of effective ways of man-caused disturbed lands reclaiming. To meet modern ecology requirements to reclaimed territories, the sediments must be safe by sanitary indices, have good organoleptic and grain-size properties, apart from being correspondent to norms by heavy metals and other toxic substances content in them. Wastes of urban sewage treatment plants were studied, as follows: raw sediments; excessive active mud, a mixture of wastes. Wastes of JSC EVRAZ ZSMK operation were used as neutralizing additives, as follows: aspiration dust of limestone burning plant, blooming scale. Studies showed a significant decrease in the content of water-soluble compounds of zinc, lead, copper, fluorine due to their precipitation when reacting with the added additives. The effectiveness of the deposition depends on the type of additive, its content, mixing conditions. By simply mixing of the neutralizing additive with the sample under investigation, a decrease of concentration of water-soluble compounds of zinc, copper, and fluorine was achieved. The selective effect of additives on individual elements established. Lime dust provided an excellent effect on zinc – a decrease by 50%, but had no effect on copper. The addition of scale led to a 25% reduction in the content of water-soluble copper, but did not lead to zinc precipitation. Regarding fluorine, lime was significantly more effective (a decrease by 53%) comparing with scale (a decrease of 27%). The total reduction of water-soluble compounds of the elements under study was 32.2% for lime and 32.6% for scale. Mixing the raw sediment with a neutralizing additive under heating conditions contributed to a significant increasing effect regarding copper: the decrease of its water-soluble ions down to 77% was obtained.

Water-soluble copper(i) complexes bearing 2,2′-bicinchoninic acid dipotassium salt with red-light absorption and repeatable colour change upon freezing operation

The repeatable colour change upon freezing–melting operation of a water solution of a Cu(i) complex is found. Efficient red light absorption is also one of the advantages of this complex.