Complexation Of Copper Ions Research Articles

A sequential treatment strategy by copper ion-doped nanofiber dressing for highly efficient biofilm combating and rapid wound healing

Copper ions are considered as a promising alternative to combat infected wound and accelerate wound healing. However, exhibiting good antibiofilm activity meanwhile minimizing cell toxicity remains a great challenge. To address this issue, we provide a sequential treatment strategy to combat biofilm infected wound with low copper ion (Cu2+) release (as low as 1.2 μg·mL−1). Polydopamine (PDA) adherent copper ion complex is constructed on thermoplastic polyurethane (TPU) to develop the Cu2+@PTPU nanofibers. With the application of Cu2+@PTPU wound dressing, nitric oxide (NO) gas is released by catalyzing endogenous donor, thereby rapidly eliminating more than 90 % biofilm biomass. Subsequent moderate photothermal treatment (∼47℃) significantly enhanced bactericidal effect by deconstructing bacteria membrane. As a result, the biofilm infection was eradicated in only ∼ 6h, significantly more effective than existing methods (∼24 h). Additionally, Cu2+@PTPU dressing not only exhibits excellent cell compatibility, but also promotes wound healing. In vivo study demonstrates that it reduces the level of inflammatory responses by 104 % and increases angiogenesis capacity by 115 %, compared with untreated group, thereby narrowing the wound site area by 72 % at day 14 after treatment. Overall, the Cu2+@PTPU dressing and sequential treatment strategy provide quick, safe, yet efficacious biofilm combating outcomes and facilitates rapid wound healing.

Tri-source integrated adenosine triphosphate complexed copper ions anchored to boron nitride surfaces for enhancing flame protection of waterborne epoxy coatings

The abundant C, P, and N elements in the structure of adenosine triphosphate (ATP) can act as carbon, acid, and gas sources, and thus can be used as an efficient intumescent flame retardant. Here, a layer of polydopamine (PDA) with polyhydroxyl groups was firstly loaded on the surface of BN to provide a bridging effect for the surface modification of BN. Then, ATP-Cu was immobilized on the BN surface by complexation of ATP with Cu2+, resulting in an efficient inorganic-organic-metal composite flame retardant (BNP@ATP-Cu). This composite flame retardant effectively combined the high barrier effect of BN, the high swelling property of ATP and the catalytic carbon formation activity of Cu2+. The experimental results revealed that the EP loaded with BNP@ATP-Cu showed the lowest backside temperature (171.2 °C), indicating the highest thermal barrier effect. Moreover, BNP@ATP-Cu/EP exhibited the most significant swelling characteristics (22.7 mm, 17.46) and smoke suppression effect (42.8 %). In contrast, the carbon residue of BNP@ATP-Cu/EP (30.8 %) was significantly higher than that of the other coated samples, which was related to the combined effect of BN and ATP-Cu. The above relevant results fully demonstrated the effectiveness of the composite flame retardants in improving the fire resistance of epoxy coatings.

New BDNF and NT-3 Cyclic Mimetics Concur with Copper to Activate Trophic Signaling Pathways as Potential Molecular Entities to Protect Old Brains from Neurodegeneration.

A low level of Neurotrophins (NTs), their Tyrosine Kinase Receptors (Trks), Vascular Endothelial Growth Factors (VEGFs) and their receptors, mainly VEGFR1 and VEGFR2, characterizes AD brains. The use of NTs and VEGFs as drugs presents different issues due to their low permeability of the blood-brain barrier, the poor pharmacokinetic profile, and the relevant side effects. To overcome these issues, different functional and structural NT mimics have been employed. Being aware that the N-terminus domain as the key domain of NTs for the binding selectivity and activation of Trks and the need to avoid or delay proteolysis, we herein report on the mimicking ability of two cyclic peptide encompassing the N-terminus of Brain Derived Growth Factor (BDNF), (c-[HSDPARRGELSV-]), cBDNF(1-12) and of Neurotrophin3 (NT3), (c-[YAEHKSHRGEYSV-]), cNT3(1-13). The two cyclic peptide features were characterized by a combined thermodynamic and spectroscopic approach (potentiometry, NMR, UV-vis and CD) that was extended to their copper(II) ion complexes. SH-SY5Y cell assays show that the Cu2+ present at the sub-micromolar level in the complete culture media affects the treatments with the two peptides. cBDNF(1-12) and cNT3(1-13) act as ionophores, induce neuronal differentiation and promote Trks and CREB phosphorylation in a copper dependent manner. Consistently, both peptide and Cu2+ stimulate BDNF and VEGF expression as well as VEGF release; cBDNF(1-12) and cNT3(1-13) induce the expression of Trks and VEGFRs.

ESR, UV–vis–NIR and FTIR spectroscopic characterization of charge carriers in copper salen polymeric complexes

In this work, we present spectroscopic investigation of charge carriers in copper(II) salen-type polymeric complexes. The polymers comprising monomeric complexes of copper(II) ion with N2O2 Schiff base ligands are analyzed to understand the influence of the paramagnetic metal center and electron-donating substituents in the ligand on the spectroscopic properties of oxidized polymers. Potential-driven structural changes in the polymeric complexes were monitored using electron spin resonance (ESR), ultraviolet−visible − near infrared (UV−vis − NIR) and Fourier Transform Infrared (FTIR) spectroelectrochemistry. By EPR spectroelectrochemistry, we gained insight into the magnetic properties of charge carriers formed during the initial and deep oxidation of the polymers as well as the interactions between the Cu(II)–ligand spins and ligand–ligand ones. By FTIR spectroelectrochemistry, it has been shown that the charge in the low doped polymers is delocalized within the whole repeat unit.

In-situ complexation of Cu(II) with polyethyleneimine (PEI) triggers the enhanced formation of halonitromethanes, dichloroacetonitrile, and dichloroacetamide during UV/chlorine disinfection: Cu(I) contribution and Cl· sustainable production

The complexation of copper ions (Cu(II)) with coexisting organic ligands (e.g. polyethyleneimine (PEI)) in water may pose a new threat to water quality. This study revealed that the maxima concentrations of HNMs, DCAN, and DCAcAm from Cu(II)-PEI complex during UV/chlorine disinfection were 1.54, 2.00, and 1.25 times higher than those from PEI, and the maxima concentrations of HNMs, DCAN, and DCAcAm from Cu(II)-PEI complex during chlorination disinfection were 1.22, 1.31, and 1.10 times higher than those from PEI. Meanwhile, specific Cu(II) concentration (0.25 ∼ 3.0 mg L−1) and alkaline pH were more favorable for forming HNMs, DCAN, and DCAcAm during UV/chlorine disinfection, which were highly dependent on the involvement of HO· and Cl·. Cu(II)-PEI, an in-situ formed stable complex that permitted an efficient interconversion cycle of Cu(II)/Cu(I) via concurrent metal-to-ligand charge transfer and ligand-to-metal charge transfer. The analysis and comparison of extensive products provided solid evidence for the primary role of Cu(I) and the enhanced production of Cl· in increasing HNMs, DCAN, and DCAcAm productions, rather than only Cu(II) catalysis similar to that during chlorination. The new findings broaden the knowledge of the influence of in-situ formed Cu(II)-organic complexes on forming HNMs, DCAN, and DCAcAm during UV/chlorine disinfection.

. Comparison of sorption properties of zoocompost in relation to Cd2+, Zn2+, Cu2+ ions

The study of relationships between zoocompost containing humic acids and metal ions is of great importance not only for predicting the redistribution of humic compounds and heavy metals in the environment, but also for developing methods for controlling the processes of migration of pollutants in natural environments, creating new materials for protecting the environment and remediating soils contaminated with heavy metal ions. The article compares the sorption capacity of zoocompost cultivated by the Black Lionfly fly, containing humic acids and to Zn2+, Cd2+, Cu2+ ions. It was established that with an increase in the dose of zoocompost, the concentration of heavy metal ions in the solution decreases and the cleaning efficiency reaches 94.6% for Cd2+, 75.2% for Zn2+ and 70.4% for Cu2+. A comparison of the stability constants of complex ions of cadmium, zinc and copper showed that more stable metal-humic acid complexes are formed by Cd2+ and Zn2+, while Cu2+ is characterized by a lower degree of connectivity. The obtained sorption isotherms and values of the sorption capacity of zoocompost for Cd2+ (0.490 mmol/g), Zn2+ (0.225 mmol/g) and Cu2+ (0.145 mmol/g) indicate the specific interaction between the heavy metal ions and functional groups of humic acids included in the composition of zoocompost, and also confirm the theoretical series of stability of chelates Cd < Zn < Cu.

Synthesis, X-ray and antibacterial activity of new copper(II) thiosemicarbazone complexes derived from 4-formyl-3-hydroxy-2-naphthoic acid

New thiosemicarbazone ligand derived from 4-formyl-3-hydroxy-2-naphthoic acid (H3L·CH3OH (1)) and their two copper(II) complexes with composition [Cu(H2L)Cl]2.2(dmf) (2), [Cu(H2L)NO3(dmf)] (3) were synthesized and characterized by thermal analysis, IR-, EPR- spectroscopy and single X-ray diffraction method. In both complexes the mono-deprotonated ligand coordinate tridentate to Cu(II) ion by ONS donor atoms provided by phenolic oxygen, azomethine nitrogen and thiol sulfur. In 2 binuclear complex has the square–planar environment of one copper(II) completed by Cl- anion, while a tetragonal pyramid of other metal is formed by Cl- anion and S atom from the neighboring organic ligand. The copper ion in the mononuclear complex 3 adopt a square-pyramidal structure, where the coordination number of copper(II) ion is adjusted to 5 by O atoms of NO3− anion and dimethylformamide molecule. Magnetic investigations of complex 2 revealed the presence of noticeable magnetic couplings between Cu(II) ions, while compound 3 shows the behavior typical of magnetically isolated Cu(II) centers. The compounds tested against St. aureus, C. albicans, E. coli and Kl. Pneumonia were found to be more active against gram-positive bacteria strains.

Study of Structural Elucidation, Degradation Kinetics and Antimicrobial Analysis of Copper (II) Sesame-Soap Complexes with Urea and Thiourea Ligand in Non-aqueous Solvents

Abstract: Surfactants have great importance in biological and drug industries and the complexes of metallic soaps with various ligands are used in approximately every region of national economy. Therefore, our keen interest to study of degradation kinetics and biological importance of Cu (II) surfactants in non-aqueous and non-polar solvent benzene. Present research work has been initiated with synthesis, systematic study of structural elucidation, thermal degradation, kinetics and biocidal activities of copper (II) sesame-soap complexes with macrocyclic nitrogen and sulphur containing donar ligands like urea and thiourea. The thermal degradation of copper (II) sesame-soap complexes were carried out for analysis of degradation kinetics and estimation of kinetic and thermodynamic parameters using different methods at heating rate 10oC min-1. Copper (II) sesame-soap complexes of such ligands have also been analysed against Staphylococus aureus. This research work consolidates the synthesis of copper (II) sesame soap-urea and thiourea complexes by conventional methods and the structure of these complexes were assigned according to elemental analysis and molecular weight determinations. IR, NMR and ESR spectral studies have also been done to understand structural aspects. The anti-microbial activities of copper (II) sesame-soap urea and thiourea complexes have been evaluated by testing against Staphylococus aureus. The present research work includes information of thermal analysis using TGA technique to find out their kinetic and thermodynamic parameters by using diverse equations such as Coats-Redfern equation, Horowitz-Metzger equation, Broido equation, Piloyan–Novikova equation. Moreover, the results obtained from anti-microbial screening have been used to analyze the anti-microbial activities of copper (II) sesame-soap urea and thiourea complexes against gram-positive bacteria Staphylococus aureus. These results show that complexes of copper ion co-ordinated with different nitrogen, oxygen and sulphur containing ligands, are very important in the field of pharmaceutical chemistry due to its significant role in the inhibition activity. The study of these complexes concludes that the synthesized complexes were found to possess appreciable bactericidal properties at different concentrations because chelation increases the anti-microbial potency.

Development of Sustainable and Active Food Packaging Materials Composed by Chitosan, Polyvinyl Alcohol and Quercetin Functionalized Layered Clay.

In order to solve the problems of insufficient active functions (antibacterial and antioxidant activities) and the poor degradability of traditional plastic packaging materials, biodegradable chitosan (CS)/polyvinyl alcohol (PVA) nanocomposite active films reinforced with natural plant polyphenol-quercetin functionalized layered clay nanosheets (QUE-LDHs) were prepared by a solution casting method. In this study, QUE-LDHs realizes a combination of the active functions of QUE and the enhancement effect of LDHs nanosheets through the deposition and complexation of QUE and copper ions on the LDHs. Infrared and thermal analysis results revealed that there was a strong interface interaction between QUE-LDHs and CS/PVA matrix, resulting in the limited movement of PVA molecules and the increase in glass transition temperature and melting temperature. With the addition of QUE-LDHs, the active films showed excellent UV barrier, antibacterial, antioxidant properties and tensile strength, and still had certain transparency in the range of visible light. As QUE-LDHs content was 3 wt%, the active films exhibited a maximum tensile strength of 58.9 MPa, representing a significant increase of 40.9% compared with CS/PVA matrix. Notably, the UV barrier (280 nm), antibacterial (E. coli) and antioxidant activities (DPPH method) of the active films achieved 100.0%, 95.5% and 58.9%, respectively. Therefore, CS/PVA matrix reinforced with QUE-LDHs has good potential to act as an environmentally and friendly active packaging film or coating.

Exploring copper (II) porphyrin complexes and their derivatives for electrochemical analysis and biological assessment in the study of breast cancer (MCF-7) cell lines

In this study, several derivatives of tetraphenylporphyrin were synthesized, each with unique meso-substituent groups including phenyl, methoxyphenyl, butyloxyphenyl, octyloxyphenyl, and dectyloxyphenyl. Additionally, their corresponding copper complexes were prepared and thoroughly characterized. The structural confirmation of all compounds was established through CHN elemental analysis, mass spectrometry, and FT-IR spectroscopy. As the number of carbon atoms in the alkyl long-chain increased, a slight red shift in the electronic absorption band was observed, which was attributed to the electronic influence of the alkyl group. DFT analysis indicated that electron density predominantly localized on the porphyrin ring of both the metal free porphyrins and copper (II) porphyrin complexes, with relatively low electron density in the p orbital of the meso-aryl long-chain substituent group. EPR spectroscopy of the Copper (II) ion complexes revealed signals, indicating their paramagnetic properties. Additionally, the Copper (II) tetraphenylporphyrin (CuTPP) complexes displayed two reversible oxidation peaks at +0.97 V and +1.35 V, whereas other derivatives exhibited lower oxidation potentials. The cytotoxicity of these compounds against MCF-7 cell lines was assessed using MTT assay, revealing cytotoxic effects in all cases. Among them, Copper (II) tetrakis (4-methyloxyphenyl)porphyrin (CuTOMPP) demonstrated the highest potential, with an IC50 value of 32.07 μg/mL.

The role of ion dissolution in metal and metal oxide surface inactivation of SARS-CoV-2.

Anti-viral surface coatings are under development to prevent viral fomite transmission from high-traffic touch surfaces in public spaces. Copper's anti-viral properties have been widely documented, but the anti-viral mechanism of copper surfaces is not fully understood. We screened a series of metal and metal oxide surfaces for anti-viral activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease (COVID-19). Copper and copper oxide surfaces exhibited superior anti-SARS-CoV-2 activity; however, the level of anti-viral activity was dependent on the composition of the carrier solution used to deliver virus inoculum. We demonstrate that copper ions released into solution from test surfaces can mediate virus inactivation, indicating a copper ion dissolution-dependent anti-viral mechanism. The level of anti-viral activity is, however, not dependent on the amount of copper ions released into solution per se. Instead, our findings suggest that degree of virus inactivation is dependent on copper ion complexation with other biomolecules (e.g., proteins/metabolites) in the virus carrier solution that compete with viral components. Although using tissue culture-derived virus inoculum is experimentally convenient to evaluate the anti-viral activity of copper-derived test surfaces, we propose that the high organic content of tissue culture medium reduces the availability of "uncomplexed" copper ions to interact with the virus, negatively affecting virus inactivation and hence surface anti-viral performance. We propose that laboratory anti-viral surface testing should include virus delivered in a physiologically relevant carrier solution (saliva or nasal secretions when testing respiratory viruses) to accurately predict real-life surface anti-viral performance when deployed in public spaces.IMPORTANCEThe purpose of evaluating the anti-viral activity of test surfaces in the laboratory is to identify surfaces that will perform efficiently in preventing fomite transmission when deployed on high-traffic touch surfaces in public spaces. The conventional method in laboratory testing is to use tissue culture-derived virus inoculum; however, this study demonstrates that anti-viral performance of test copper-containing surfaces is dependent on the composition of the carrier solution in which the virus inoculum is delivered to test surfaces. Therefore, we recommend that laboratory surface testing should include virus delivered in a physiologically relevant carrier solution to accurately predict real-life test surface performance in public spaces. Understanding the mechanism of virus inactivation is key to future rational design of improved anti-viral surfaces. Here, we demonstrate that release of copper ions from copper surfaces into small liquid droplets containing SARS-CoV-2 is a mechanism by which the virus that causes COVID-19 can be inactivated.

Synthesis, characterization and theoretical aspects of copper and zinc divalent ion complexes with azo dye derived from 4,5-diphenylimidazole

Azo dye ligand derived from 4,5-diphenyl imidazole and 4,4-diaminodiphenylmethane was synthesized by diazomium coupling reaction. In this reaction an amine (4,4-diaminodiphenylmethane was converted to the diazonium salt and coupled with 4,5-diphenyl imidazole. The bright coloured Cu(II) and Zn(II) complexes with this ligand were synthesized by refluxing the latest with both metals chloride salts. The prepared compounds were characterized by 1H-NMR, 13C-NMR, FTIR, UV-Visible, molar conductivity and atomic absorption. By the infrared data, the coordination between copper and zinc ions and the azo ligand achieved through the nitrogen of the azo group and one of the nitrogen atoms in the imidazole ring. By the molar conductivity test, the non- electrolytic nature of both complexes was also confirmed. The suggested structure for these complexes is octahedral. Using density functional theory (DFT) some theoretical data was obtained for the synthesized complexes. The obtained data include the highest occupied and the lowest unoccupied molecular orbitals energy (HOMO and LUMO), electron density, thermodynamic functions (ΔG°, ΔS°, ΔH°, ΔE°), ionization potential (IP), electron affinity (EA), electrophilicity(ὠ), electronegativity (En), chemical hardness (η) and dipole moment (μ). According to these studied parameters some properties of the two complexes were explained and discussed.
 KEY WORDS: Cu(II) and Zn(II) complexes, Azo ligand, 4,5-Diphenylimidazole, 4,4-Diaminodiphenylmethane, Theoretical study
 Bull. Chem. Soc. Ethiop. 2024, 38(2), 313-323. 
 DOI: https://dx.doi.org/10.4314/bcse.v38i2.4

Synthesis of a novel nanomagnetic N4 bis schiff base complex of copper(ii) as an efficient catalyst for click synthesis of tetrazoles.

In this study, we have prepared a novel bis-Schiff-base copper(ii) complex by modifying Fe3O4 with acetylacetone functionalities and subsequently forming a Schiff base with 2-picolylamine and CuCl2 through a template method. Immobilization of 2,4-pentanedione and its reaction with 2-picolylamine enabled the synthesis of 1,3-diketimines (HNacNac) as an anionic ligand. This unique design resulted in a tetradentate N4 coordination sphere for copper(ii) ion complexation. The resulting heterogeneous catalyst, [Fe3O4@Sil-Schiff-base-Cu(ii)], efficiently catalyzed the click condensation of diverse aryl nitriles with sodium azide to produce 5-substituted 1H-tetrazoles in high yields and selectivity. The catalyst demonstrated remarkable stability and recyclability without appreciable loss of catalytic activity, as confirmed by hot filtration and reusability studies.

Preliminary Investigation of Copper(II) Ion Binding or Complex Coordination in Lysozeme Molecules

Preliminary Investigation of Copper(II) Ion Binding or Complex Coordination in Lysozeme Molecules

8-hydroxyquinoline-N-oxide copper(II)- and zinc(II)-phenanthroline and bipyridine coordination compounds: Design, synthesis, structures, and antitumor evaluation

Fourteen novel tumor-targeting copper(II) and zinc(II) complexes, [Cu(ONQ)(QD1)(NO3)]·CH3OH (NQ3), [Cu(ONQ)(QD2)(NO3)] (NQ2), [Cu(NQ)(QD2)Cl] (NQ3), [Cu(ONQ)(QD1)Cl] (NQ4), [Cu(ONQ)(QD3)](NO3) (NQ5), [Cu(ONQ)(QD3)Cl] (NQ6), [Zn(ONQ)(QD4)Cl] (NQ7), [Zn(ONQ)(QD1)Cl] (NQ8), [Zn(ONQ)(QD5)Cl] (NQ9), [Zn(ONQ)(QD2)Cl] (NQ10), [Zn(ONQ)(QD6)Cl] (NQ11), [Zn(ONQ)(QD7)Cl] (NQ12), and [Zn(ONQ)(QD3)Cl] (NQ13) supported on 8-hydroxyquinoline-N-oxide (H-ONQ), 2,2′-dipyridyl (QD1), 5,5′-dimethyl-2,2′-bipyridyl (QD2), 1,10-phenanthroline (QD3), 4,4′-dimethoxy-2,2′-bipyridyl (QD4), 4,4′-dimethyl-2,2′-bipyridyl (QD5), 5-chloro-1,10-phenanthroline (QD6), and bathophenanthroline (QD7), were first synthesized and characterized using various spectroscopic techniques. Furthermore, NQ1–NQ13 exhibited higher antiproliferative activity and selectivity for cisplatin-resistant SK-OV-3/DDP tumor cells (CiSK3) compared to normal HL-7702 cells based on results obtained from the cell counting Kit-8 (CCK-8) assay. The complexation of copper(II) ion with QD2 and ONQ ligands resulted in an evident increase in the antiproliferation of NQ1–NQ6, with NQ6 exhibiting the highest antitumor potency against CiSK3 cells compared to NQ1–NQ5, H-ONQ, QD1–QD7, and NQ7–NQ13 as well as the reference cisplatin drug with an IC50 value of 0.17 ± 0.05 μM. Mechanistic studies revealed that NQ4 and NQ6 induced apoptosis of CiSK3 cells via mitophagy pathway regulation and adenosine triphosphate (ATP) depletion. Further, the differential induction of mitophagy decreased in the order of NQ6 > NQ4, which can be attributed to the major impact of the QD3 ligand with a large planar geometry and the Cl leaving group within the NQ6 complex. In summary, these results confirmed that the newly synthesized H-ONQ copper(II) and zinc(II) coordination metal compounds NQ1–NQ13 exhibit potential as anticancer drugs for cisplatin-resistant ovarian CiSK3 cancer treatment.

Ammonium-Amine Co-Activation: Promoting the Sulfurization of Azurite and Its Effect on Xanthate Adsorption.

Enhanced sulfurization has always been the focus of research on the flotation of copper oxide minerals. In this study, combined ammonium-amine salts were innovatively applied to improve the sulfurization of azurite. Flotation tests were carried out to evaluate the promoting effect of ammonium-amine co-activation on the sulfurization-xanthate flotation of azurite, and the microstructure evolution of sulfurized products was investigated to reveal the mechanism underlying this promoting effect. Compared with single ammonium (amine) salt activation, ammonium-amine co-activation improved the floatability of azurite to a greater extent, i.e., the flotation recovery increased by over 4 percentage points. ToF-SIMS, ICP-OES, FESEM-EDS, AFM, XRD, and UV-vis analyses indicated that ammonium-amine co-activation combined the advantages of inorganic ammonium for buffering pH and organic amine for copper ion complexation, thus promoting the growth of sulfurized crystal products (covellite) and enhancing the adhesion stability of sulfurized products on azurite. Therefore, increasing amounts of copper sulfide components were generated under the ammonium-amine-Na2S system, promoting the adsorption of additional xanthate on azurite. This study provides theoretical support for the application of combined ammonium-amine salts for the sulfurization flotation of copper oxide.

Dual techniques for trace copper determination: DES/Dithizone based liquid phase microextraction-flame atomic absorption spectrophotometry and digital image based colorimetric probe

In this study, a sample preparation procedure was developed to preconcentrate copper ions from aqueous samples for determination by flame atomic absorption spectrometry (FAAS) and digital image based colorimetry (DIC) systems. This was achieved by complexing copper ions with dithizone (Cu-DZ) and extracting the complex from aqueous solution in a single step. For the DES/DZ-FAAS system, a low detection limit of 2.3 ng mL−1 was recorded over a broad and linear working range. For the DIC system, the linear relationship between the change in red color intensity of the red–green–blue (RGB) color scale and the concentration of copper in the Cu-DZ complex was utilized for the validation of the method. The DIC system also recorded a broad and linear working range with a satisfactory detection limit of 14.7 ng mL−1. Spike recovery experiments performed with eucalyptus tea extracts yielded high recovery results in the range of 91–107%.

Photocatalytic Activity and Thermal Stability of Hybrid Metal-Polymer-Coordinated Complexes Derived from Gallic Acid and Ethylenediamine.

Three new hybrid metal-polymer-coordinated complexes (MPCs) of copper(II), cobalt(II), and nickel(II) ions with an organic polymer derived from gallic acid and ethylenediamine (GAEtH) were synthesized. The structures of GAEtH and MPCs were characterized with FT-IR, ultraviolet (UV)-Vis, 1H and 13C NMR spectroscopy, and elemental and thermogravimetric analysis. The results reveal that the organic polymer GAEtH exhibits an infinite one-dimensional chain structure, while the hybrid MPCs have a double chain structure, with the two chains joined by metal ions. The thermodynamic and kinetic parameters of the thermal degradation stages were determined by the Coats Redfern method, and the photocatalytic behaviors of the MPCs were investigated through the decomposition of methyl orange dye under UV irradiation.

Copper(II), Cobalt(II), Nickel(II) And Zinc(II) Complexes Obtained From Dipicolinic Acid And Morpholine: Synthesis, Characterization, Biological Evaluation And In Silico Studies

With morpholinium counter ion a set of new complexes of Copper(II), Cobalt(II), Nickel(II) and Zinc(II) ions were synthesized and characterized. UV-visible, IR, powder XRD and thermal studies have been utilized to characterize the synthesized complexes. The structures of the complexes were optimized using DFT studies and screened for their antioxidant and anti-inflammatory activities. The results of In vitro antioxidant and anti-inflammatory activity studies indicated the appreciable biological activity of the synthesized complexes. All the synthesized complexes exhibited very good stability under physiological conditions for 72 h. Molecular docking studies performed with cyclooxygenase enzymes (COX-1 and COX-2) revealed the significant interaction between the complexes and the enzymes through many hydrogen bonds with very good binding energies.

Does the aging behavior of microplastics affect the process of denitrification by the difference of copper ion adsorption?

Riparian sediment is a hot zone for denitrification that can withhold copper and microplastics (MPs) from outside. It has been proven that MPs affect denitrification and the existing forms of copper in the environment. However, the impact of copper on sediment denitrification under exposure to MPs remains unclear. This study revealed the response of sediment denitrification to copper availability under the adsorption of MPs and the complexation of MP-derived dissolved organic matter (DOM). These results showed that MP accumulation inhibited denitrification. However, aged MPs increased the activity of nitrite reductase (12.64%), nitrogen dioxide reductase (37.68%), and electron transport (28.93%) compared with pristine MPs. The aging behavior of MPs alleviated 28.18% nitrite accumulation and 16.41–118.35% nitrous oxide emissions. Thus, the aging behavior of MPs alleviated the inhibition of denitrification. Notably, we resolved the copper ion adsorption and complexation by MPs, MP-derived DOM contributed to the denitrification process, and we found that the key nitrogen removal factors were affected by KL, KM, and K2. These results fill a gap in our understanding of biochemical synthesis of MPs during denitrification. Furthermore, it can be used to build a predictive understanding of the long-term effects of MPs on the sediment nitrogen cycle.