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In 1983, Linus Pauling and colleagues reported about enhanced antitumor activity of the Cu(II) complex of the simplest ATCUN (amino terminal Cu(II) and Ni(II)-binding motif) peptide (NH2-Gly-Gly-His-COOH, GGH) in the presence of ascorbate as an additive. In the following 4 decades, structural modifications of this complex were implemented, however, anticancer activity could not be significantly increased. This has led to neglecting the ATCUN motif and its Cu(II) complexes as potential chemotherapeutic agents. Furthermore, the addition of ascorbate with its positive effect on the anticancer activity has fallen into oblivion. In this work, we compared Cu(II) GGH with Cu(II) ATCUN peptides bearing β-Ala instead of Gly at the 2nd position of the peptide sequence regarding their in vitro complex stability and cytotoxicity (MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and annexin V-FITC (fluorescein isothiocyanate) apoptosis assay) towards three cancer cell lines (AGS, HeLa and NCI-N87). Such an exchange of amino acids led to an up to three-fold higher cytotoxic effect in the presence of ascorbate. We thus achieved a significant increase in the otherwise moderate cytotoxicity of Cu(II) ATCUN-like complexes. Lipophilicity assays (n-octanol/water coefficient, log P values) of the studied complexes were used to evaluate differences in the antiproliferative activity. [ABSTRACT FROM AUTHOR]

In this study, we investigate the electrochemical properties of a novel copper complex (CuL2) derived from the Schiff base ligand N-3-bromopropylsalicylaldimine (LH). We also examine its interaction with chicken blood double-stranded DNA (cb-ds DNA) in phosphate buffer solution (PB) at physiological pH 7.2 using cyclic voltammetry (CV) techniques. The interaction mechanism of nitrite with CuL2, involving the CuII/CuI redox system, is explored. The CuL2 complex was electropolymerized on glassy carbon (GC) and fluorine tin oxide (FTO). The morphology of PolyCuL2 formed on FTO was analyzed using scanning electron microscopy (SEM) and its elemental composition determined by EDX analysis. The modified electrode polyCuL2/GC exhibited efficient catalytic activity for the electroreduction of oxygen (O2) in homogeneous electrocatalytic media. The binding constant (Kb) of the DNA-CuL2 adduct, determined from CV measurements, was found to be 1.33×105, closely matching the value obtained from molecular docking studies (1.75×105). Docking studies indicate that the CuL2 complex binds to DNA in the minor groove binding mode. The anodic peak potential shift in the negative direction suggests an electrostatic interaction between CuL2 and DNA. [ABSTRACT FROM AUTHOR]

Copper–semicarbazone ligands have been extensively investigated for several medicinal applications. In this contribution, a novel copper(II) complex with a pyridoxal–semicarbazone ligand, [Cu(PLSC)Cl(H2O)](NO3)(H2O), was synthesized and characterized by X-ray crystallography, elemental analysis, UV-VIS, and FTIR spectroscopies. The stabilization interactions within the structure were assessed using the Hirshfeld surface analysis. The crystallographic structure was optimized at the B3LYP/6-311++G(d,p)(H,C,N,O)/LanL2DZ(Cu) level of theory. A comparison between the experimental and theoretical bond lengths and angles was undertaken to verify the applicability of the selected level of theory. The obtained high correlation coefficients and low mean absolute errors confirmed that the optimized structure is suitable for further investigating the interactions between donor atoms and copper, along with the interactions between species in a neutral complex, using the Quantum Theory of Atoms in Molecules approach. The electrostatic potential surface map was used to reveal distinct charge distributions. The experimental and calculated FTIR spectra were compared, and the most prominent bands were assigned. The interactions with human serum albumin (HSA) were assessed by spectrofluorometric titration. The spontaneity of the process was proven, and the thermodynamic parameters of binding were calculated. Molecular docking analysis identified the most probable binding site, providing additional insight into the nature of the interactions. [ABSTRACT FROM AUTHOR]

The title compound, bis[μ-2,2′-(4H-1,2,4-triazole-3,5-diyl)diacetato]bis[diaquacopper(II)] dihydrate, [Cu2(C6H5N3O4)2(H2O)4]·2H2O, is a dinuclear octahedral CuII triazole-based complex. The central copper atoms are hexa-coordinated by two nitrogen atoms in the equatorial positions, two equatorial oxygen atoms of two carboxylate substituents in position 3 and 5 of the 1,2,4-triazole ring, and two axial oxygen atoms of two water molecules. Two additional solvent water molecules are linked to the title molecule by O—H...N and O...H—O hydrogen bonds. The crystal structure is built up from the parallel packing of discrete supramolecular chains running along the a-axis direction. Hirshfeld surface analysis suggests that the most important contributions to the surface contacts are from H...O/O...H (53.5%), H...H (28.1%), O...O (6.3%) and H...C/C...H (6.2%) interactions. The crystal studied was twinned by a twofold rotation around [100].

A new dinuclear nickel(II) complex, [Ni2(L1)2(H2O)4]Cl4·6H2O (1), and two mononuclear copper(II) complexes, [Cu(L1)2(H2O)2](NO3)2·2H2O (2) and [Cu(L2)2(H2O)2](NO3)2·2MeOH (3) (L1 = 4-(p-methoxyphenyl)-3-(2-pyridyl)-5-(2-pyrimidinyl)-1,2,4-triazole, L2 = 4-(p-methylphenyl)-3-(2-pyridyl)-5-(2-pyrimidinyl)-1,2,4-triazole), have been synthesized and characterized by elemental analysis, IR, PXRD, and single-crystal X-ray crystallography. The crystal structure analysis shows that the [Ni2N8] unit in 1 is almost planar, in which each Ni(II) ion is coordinated by four nitrogen atoms from L1 equatorially and two water molecules axially in a distorted octahedral [NiN4O2] geometry. In complexes 2 and 3, the six-coordinated Cu(II) cation displays a distorted octahedral [CuN4O2] configuration. The intermolecular interactions in 1–3 have been investigated by 3D Hirshfeld surface analyses and 2D fingerprint plots to show that the prominent interactions are H···H and C···H/H···C contacts in 1, and H···H and N···H/H···N contacts in both 2 and 3. Furthermore, variable-temperature magnetic susceptibility of 1 indicates that there is a weak antiferromagnetic interaction between the two Ni(II) ions with J = −13.8(6) cm−1. [ABSTRACT FROM AUTHOR]

A new purine derivative, namely 6-methoxy-N7-methylpurine, with the molecular formula (C7H8N4O) was synthesized and its copper(II) complex was studied in the solid state for interaction. It is found that a highly insoluble μ-dichloro-bis-copper complex forms, wherein N3 and N9 nitrogen atoms form purine and participate in bonding. Further, the antimicrobial activity was evaluated against gram-negative, gram-positive, and fungus strains and found significant activity compared with ciprofloxacin and fluconazole. This activity was well supported by molecular docking lower binding interaction with complex and protein DNA gyrase. [ABSTRACT FROM AUTHOR]

The title compound, bis[μ-2,2′-(4H-1,2,4-triazole-3,5-diyl)diacetato]bis[diaquacopper(II)] dihydrate, [Cu2(C6H5N3O4)2(H2O)4]·2H2O, is a dinuclear octahedral CuII triazole-based complex. The central copper atoms are hexa-coordinated by two nitrogen atoms in the equatorial positions, two equatorial oxygen atoms of two carboxylate substituents in position 3 and 5 of the 1,2,4-triazole ring, and two axial oxygen atoms of two water molecules. Two additional solvent water molecules are linked to the title molecule by O—H⋯N and O⋯H—O hydrogen bonds. The crystal structure is built up from the parallel packing of discrete supramolecular chains running along the a-axis direction. Hirshfeld surface analysis suggests that the most important contributions to the surface contacts are from H⋯O/O⋯H (53.5%), H⋯H (28.1%), O⋯O (6.3%) and H⋯C/C⋯H (6.2%) interactions. The crystal studied was twinned by a twofold rotation around [100]. [ABSTRACT FROM AUTHOR]

In this study, the copper(II) complex [Cu(chromoneTSC)Cl2]•0.5H2O•0.0625C2H5OH (where chromoneTSC = (E)-N-Ethyl-2-((4-oxo-4H-chromen-3-yl)methylene)-hydrazinecarbothioamide) was synthesized and characterized; then used to carry out in vitro studies in combination with berberine chloride (BBC). The ligand and complex were characterized by elemental analysis, FTIR and NMR (1H and 13C) spectroscopy, and conductivity measurements. The cytotoxic effect was analyzed by using the CCK-8 viability assay in cancer MDA-MB-231 VIM RFP and non-cancer MCF-10A cell lines. The IC50 values for the complex and BBC were 21.2 ± 1.6 and 48.3 ± 2.4 μM, respectively at 24 h incubation, while the IC50 value of the combination treatment was 9.3 ± 1.5 in cancer cells. The co-treatment group significantly increased the number of cells in G2 phase, indicating the growth arrest of cancer cells. Moreover, the combination group showed induction of both intrinsic and extrinsic apoptotic pathways. There was also a study on the effect of the combination treatment on receptor-interacting serine/threonine-protein kinase 3 (RIPK3) and mixed lineage kinase domain-like pseudokinase (MLKL) as biomarkers of necroptosis. The results showed activation of necroptosis after treatment with the combination of the copper complex and BBC via the activation of RIPK3–MLKL pathway.

In the present work, a novel coordination polymer {[Cu(phen)(Tmdipy)(NO3)H2O](NO3) 2.5(H2O)}n (phen = 1,10-phenanthroline, Tmdipy = 4,4′- Trimethylenedipyridine), has been prepared and structurally determined by elemental analysis, IR, EPR, UV–visible and single-crystal X-ray crystallography. The complex crystallized in triclinic space group P -1, and the copper(II) shows a distorted octahedral geometry, with Jahn-Teller distortion occurring in the (4 + 2) CuN4O2 coordination sphere. The crystal structure evidences that the CP1 is formed of dinuclear [Cu(phen)(Tmdipy)(NO3)(H2O)]2 units weakly connected by nitrate anions giving rise to 1D polymeric chain structure. EPR measurement confirms about the distorted octahedral geometry of the complex. By using UV–Vis absorption, fluorescence spectroscopy, and cyclic voltammetric techniques, the binding studies of copper(II) complex with calf thymus DNA (CT-DNA) were investigated. Additionally, the gel electrophoresis method was used to examine the cleavage of pBR322 DNA by copper(II) complex and exhibited potent cytotoxic effects against human cell line (HepG2). Finally, magnetic properties, molecular docking studies and photoluminescence characteristics have been evaluated.

This articles describes the preparations of a series of Schiff base ligands [L1], [L2], and [L3] and their corresponding copper(II) complexes; [C1], [C2] and [C3]. The synthesized ligands and their copper(II) complexes were characterized using Fourier Transform Infrared (FTIR), Nuclear Magnetic Resonance (NMR) and Ultraviolet-visible (UV-Vis) spectroscopy. The ability of the compounds to inhibit bacteria species were tested against E. Coli, Staphyllococcus and Streptococcus bacterial. The results revealed that all the compounds were active against bacteria species. The inhibition rate is in order L3>L2>L1 for ligands and C3>C2>C1 for complexes. The catalytic activities of the synthesized copper(II) complexes were evaluated in the reduction of aromatic compounds in the presence of sodium borohydride which acts as reducing agent. The progress of reaction was monitored using UV-visible spectroscopy and the percentage conversion was determined from the spectroscopy data. The results showed that [C3] has the highest catalytic activities with 97.5% conversion, followed by [C2] complex with 95.2% conversion, then [C1] complex with 90.8% conversion. The optimization of the catalyst dose shows that 1.0 mg of the catalyst dose was the most optimized amount with the highest conversion of 94.6% than other dose of 0.5 mg (92.4%) and 1.5 mg (91.4%). Recyclability and reproducibility tests of copper(II) complexes confirmed that all the three complexes were active, efficient and possess excellent reproducibility with consistent catalytic performances and could be re-used again without significant decrease in the catalytic activities. [ABSTRACT FROM AUTHOR]

A complex of Cu(II) with a bidentate Schiff base, salicylaldehyde salicyloyl hydrazone (SSH), was synthesized by refluxing copper(II) chloride with this ligand. The formation of the complex, the nature of bonding, and the geometry of the complex were established via physicochemical and spectroscopic techniques. The composition of the complex was found to be a 1:2 metal-ligand ratio as Cu(SSH)2. Electronic absorption spectral studies revealed that the copper adopts a distorted tetrahedral geometry upon complexation with SSH. The optical band energy for the complex was determined from absorption spectroscopy. The obtained band gap of 2.66 eV characterizes the complex as a semiconductor. The most stable conformations of the Schiff base (SSH) and Cu(SSH)2 complex have been computed, shedding light on their structural and electronic properties, and highlighting their potential reactivity and stability. The ligand exhibits a higher reactivity towards electrophiles, while the complex displays a greater affinity for nucleophiles. The in vitro antibacterial analysis with agar cup well method and in silico molecular docking analysis indicate that both the ligand and its complex with copper have potency to inhibit bacterial infections. Based on their growth inhibition, minimum inhibitory concentration (MIC) values, and robust interaction with studied proteins of the pathogens, these compounds hold a prospective avenue for the advancement of antibiotics. [ABSTRACT FROM AUTHOR]

Under ultrasound irradiation in an ethanol solvent, a new coordination complex of Cu(II) was successfully synthesized within a 10-min timeframe through the treatment of an imidazole-based ligand (PDI) with a copper-containing salt. The formation of the complex was verified through elemental (CHN) analysis and FT-IR spectroscopy. Additionally, the supramolecular assembly and packing of atoms in the crystalline units of the copper complex were elucidated using single-crystal X-ray diffraction method. The synthesized compound exhibits an ionic nature, featuring a copper(II) cation inside the coordination sphere and a chloride anion outside of the coordination sphere. The coordination environment around the copper cation is achieved through the bonding of the N-atom of the non-protonated PDI ligands and a chloride ion. To maintain a neutral charge, a second chloride ion serves as a counterion. The bond angles surrounding the Cu(II) ion showed a somewhat deformed square planar geometry of the complex. The non-covalent intermolecular interactions were executed by Hirshfeld surface analysis (HSA), while the theoretical studies were conducted using DFT employing the B3LYP/Def2-TZVP level of theory. The consistency between the theoretical findings and experimental data attested to the reliability of the theoretical conclusions. [ABSTRACT FROM AUTHOR]

A reaction between copper(II) nitrate and trans-1,4-cyclohexanedicarboxylic acid (H2chdc) carried out under hydrothermal conditions led to a new metal-organic coordination polymer [Cu2(Hchdc)2(chdc)]n. According to single-crystal XRD data, the compound is based on bi-nuclear paddlewheel-type carboxylate blocks that are joined with polymeric chains due to the (μ3-κ1:κ2) coordination of carboxylate groups. The chains are interconnected by chdc2− bridging ligands into layers containing free COOH groups of terminal Hchdc−. The neighboring layers adopt a RCOOH···OOCR hydrogen bond-assisted arrangement into a dense-packed structure. Magnetization measurements showed the presence of a strong antiferromagnetic exchange interaction (J/kB = −495 K) inside the bi-nuclear blocks. At the same time, no significant interaction was found between the {-Cu2(OOCR)4-} units in spite of their polymeric in-chain packing. Patterns of magnetic behavior of [Cu2(Hchdc)2(chdc)]n were thoroughly analyzed and explained from a structural point of view. [ABSTRACT FROM AUTHOR]

The title copper(II) complex, [Cu(C18H19N3O3)(C3H4N2)], consists of a tridentate ligand synthesized from L-leucine and azobenzene-salicylaldehyde. One imidazole molecule is additionally coordinated to the copper(II) ion in the equatorial plane. The crystal structure features N—H...O hydrogen bonds. A Hirshfeld surface analysis indicates that the most important contributions to the packing are from H...H (52.0%) and C...H/H...C (17.9%) contacts.

Copper–semicarbazone ligands have been extensively investigated for several medicinal applications. In this contribution, a novel copper(II) complex with a pyridoxal–semicarbazone ligand, [Cu(PLSC)Cl(H2O)](NO3)(H2O), was synthesized and characterized by X-ray crystallography, elemental analysis, UV-VIS, and FTIR spectroscopies. The stabilization interactions within the structure were assessed using the Hirshfeld surface analysis. The crystallographic structure was optimized at the B3LYP/6-311++G(d,p)(H,C,N,O)/LanL2DZ(Cu) level of theory. A comparison between the experimental and theoretical bond lengths and angles was undertaken to verify the applicability of the selected level of theory. The obtained high correlation coefficients and low mean absolute errors confirmed that the optimized structure is suitable for further investigating the interactions between donor atoms and copper, along with the interactions between species in a neutral complex, using the Quantum Theory of Atoms in Molecules approach. The electrostatic potential surface map was used to reveal distinct charge distributions. The experimental and calculated FTIR spectra were compared, and the most prominent bands were assigned. The interactions with human serum albumin (HSA) were assessed by spectrofluorometric titration. The spontaneity of the process was proven, and the thermodynamic parameters of binding were calculated. Molecular docking analysis identified the most probable binding site, providing additional insight into the nature of the interactions.

Copper(II), nickel(II) and zinc(II) complexes of various peptide fragments of tau protein were studied by potentiometric and spectroscopic techniques. All peptides contained one histidyl residue and represented the sequences of tau(91–97) (Ac-AQPHTEI-NH2), tau(385–390) (Ac-KTDHGA-NH2) and tau(404–409) (Ac-SPRHLS-NH2). Imidazole-N donors of histidine were the primary metal binding sites for all peptides and all metal ions, but in the case of copper(II) and nickel(II), the deprotonated amide groups were also involved in metal binding by increasing pH. The most stable complexes were formed with copper(II) ions, but the presence of prolyl residues resulted in significant changes in the thermodynamic stability and speciation of the systems. It was also demonstrated that nickel(II) and especially zinc(II) complexes have relatively low thermodynamic stability with these peptides. The copper(II)-catalyzed oxidation of the peptides was also studied. In the presence of H2O2, the fragmentation of peptides was detected in all cases. In the simultaneous presence of H2O2 and ascorbic acid, the fragmentation of the peptide is less preferred, and the formation of 2-oxo-histidine also occurs. [ABSTRACT FROM AUTHOR]

A new tetranuclear copper(II) complex [Cu4L2(N3)2(CH3OH)2](NO3)2·4CH3OH (1) and a new trinuclear zinc(II) complex [Zn3L2(CH3COO)2] (2) have been prepared from the bis-Schiff base N,N'-bis(4-bromosalicylidene)-1,3-propanediamine (H2L) with copper nitrate and zinc acetate, respectively, in the presence of sodium azide. The complexes were characterized by elemental analysis, IR and UV-Vis spectroscopy. Molecular structures of both complexes were confirmed by single crystal X-ray determination. The Cu(II) atoms in complex 1 are bridged by phenolate oxygen atoms and end-on azide ligands. The Zn(II) atoms in complex 2 are bridged by phenolate oxygen atoms and acetate ligands. The Cu(II) atoms in complex 1 are in square planar and square pyramidal coordination. The Zn(II) atoms in complex 2 are in square pyramidal and octahedral coordination. The Schiff base ligand coordinates to the metal atoms through two phenolate O and two imino N atoms. The biological assay reveals that the copper(II) complex has effective urease inhibition. [ABSTRACT FROM AUTHOR]

The title copper(II) complex, [Cu(C18H19N3O3)(C3H4N2)], consists of a tridentate ligand synthesized from l-leucine and azobenzene-salicylaldehyde. One imidazole molecule is additionally coordinated to the copper(II) ion in the equatorial plane. The crystal structure features N--H...O hydrogen bonds. A Hirshfeld surface analysis indicates that the most important contributions to the packing are from H...H (52.0%) and C...H/H...C (17.9%) contacts. [ABSTRACT FROM AUTHOR]

A new copper(II) complex with 2-amino-6-methylpyrimidin-4-(1H)-one, [Cu(C5H7N3O)4](NO3)2·H2O (Cupyrim), has been synthesized and studied by X-ray diffraction, elemental analysis and FT-IR spectroscopy. The Cu(II) is four-coordinate in a square planar geometry by four nitrogen atoms of the four organic ligands. Hirshfeld Surface Analysis was conducted to understand crystalline packing. Overall, the structure is maintained by metal coordination as well as strong and weak (C,N)–H···O hydrogen bonds and C–H...π interactions. The IR spectrum primary peaks have been assigned to the vibration modes of the ligand functional groups. An investigation of the inhibitory properties of Cupyrim toward "Cyclin-dependent Kinase 2" (CdK2) and "inducible nitric oxide synthase" (iNOS) proteins was aided by molecular docking research. According to molecular docking, Cupyrim exhibits promising inhibitory efficacy against Parkinson's, schizophrenia, and Alzheimer's disorders. The temperature dependence of the real and imaginary part of the dielectric permittivity was analyzed with the Cole-Cole formalism as well as DSC diagrams from 45-147 °C. [ABSTRACT FROM AUTHOR]

Copper(II) and zinc(II) complexes, [Cu(esct)(4-pico)] (1), [Zn(esct)(5,5′-dmbipy)]·H2O (2), [Cu(esct)(5,5′-dmbipy)] (3), (where H2esct = 3-ethoxysalicylaldehye-N4-cyclohexylthiosemicarbazone) were synthesized by reacting copper acetate/zinc acetate with the thiosemicarbazone derivative (H2esct) along with heterocyclic bases. The thiosemicarbazone forms doubly deprotonated anions in all the complexes to coordinate via thiolate S, azomethine N and phenolate O atoms. The complexes were characterized by various spectroscopic techniques like infrared, UV–vis, 1H NMR and EPR spectra. The single crystal XRD studies confirmed the structures. All the three complexes got crystallized in triclinic space group P 1 ¯. Complexes are found to have four, five and six coordination around the metal center. The importance of van der Waals interactions in them is explained by Hirshfeld surface analysis. We have used Density Functional Theory (DFT) methods and optimized ground states of the studied complexes using the Gaussian 09 package. Electrostatic potential plots of complexes were investigated. Further, docking studies were carried out with various Epidermal Growth Factor Receptor (EGFR) enzymes. Three mixed ligand Cu(II) and Zn(II) complexes prepared from a thiosemicarbazone showed interesting geometries and structures [ABSTRACT FROM AUTHOR]

Heterocyclic structures are the basic building blocks of many naturally occurring organic compounds that are important for the development of essential biological processes in plants and animals, including carbohydrates and vitamins. They are also widely used as raw material sources to produce pharmaceuticals. In this study, three ligands from the groups of benzopyrones (chromone-2-carboxylic acid) and hydroxypyrones (maltol and coumalic acid), and a newly prepared complex of copper(II) nitrate with maltol as a ligand were investigated for their ability to inhibit cell proliferation. For research purposes, a series of solutions of the tested materials were prepared at different final concentrations (10–5 mol dm–3, 10–6 mol dm–3, and 10–7 mol dm–3), and then applied to a total of 7 selected cell lines, including one healthy cell line, while the others were tumour cell lines. The results of MTT cytotoxicity assay on the selected 2D cell models showed that none of the selected ligands exhibited antiproliferative activity at any concentration on any of the tested cell lines. The complex of copper(II) nitrate and maltol, in contrast to the tested ligands at the 10–5 mol dm–3 concentration, exhibited significant cytotoxicity as follows: KATO III > HT-29 > Hep G2 > NCI-H358 > MDA-MB-231 > Caco-2 > MRC-5. The healthy cell line (MRC-5) had a survival rate higher than 90.0 % at all tested concentrations, which led to the conclusion of the selectivity of the compound towards tumour cell lines.

A reaction between copper(II) nitrate and trans-1,4-cyclohexanedicarboxylic acid (H2chdc) carried out under hydrothermal conditions led to a new metal-organic coordination polymer [Cu2(Hchdc)2(chdc)]n. According to single-crystal XRD data, the compound is based on bi-nuclear paddlewheel-type carboxylate blocks that are joined with polymeric chains due to the (μ3-κ1:κ2) coordination of carboxylate groups. The chains are interconnected by chdc2− bridging ligands into layers containing free COOH groups of terminal Hchdc−. The neighboring layers adopt a RCOOH···OOCR hydrogen bond-assisted arrangement into a dense-packed structure. Magnetization measurements showed the presence of a strong antiferromagnetic exchange interaction (J/kB = −495 K) inside the bi-nuclear blocks. At the same time, no significant interaction was found between the {-Cu2(OOCR)4-} units in spite of their polymeric in-chain packing. Patterns of magnetic behavior of [Cu2(Hchdc)2(chdc)]n were thoroughly analyzed and explained from a structural point of view.

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Two azo dye ligands, bearing different substituents (chlorine atom or methoxy group) in the para‐position of the phenyl ring, were employed for the synthesis of two Cu(II) chelates. Full structural affirmation of complexes was assessed. X‐ray diffraction measurements revealed that the coordination geometry for Cu atoms in both complexes is square‐pyramidal with a ligand:metal ratio of 2:1 where dyes behave as monobasic bidentate ligands. Thermogravimetric analyses of the complexes and their starting dyes were performed to study their thermal stabilities and decomposition behavior confirming the thermal stability of both dyes and complexes. Antioxidative activity of the complexes has been assigned and compared with their parent ligands revealing that the presence of the electron–donor, methoxy group, in the phenyl ring, in both dye and complex, is responsible for the activity (IC50 values of 1.54 for the dye and 1.30 mM for the complex). It should be stated that the complexation of the methoxy‐substituted dye leads to enhanced antioxidative activity concurrent to a standard antioxidant molecule of ascorbic acid, making this molecule a promising antioxidant agent. Docking study with vascular endothelial growth factor receptor 2 and Aurora kinase A proteins indicate that complexes exhibit higher binding affinities to proteins than the starting ligand dyes. The most promising structure exhibiting the best docking potential toward both proteins is the complex‐bearing methoxy group. The presented results represent a promising start for further investigations of these compounds as potential therapeutic candidates for the treatment of various types of cancer. [ABSTRACT FROM AUTHOR]

Topoisomerases are interesting targets in cancer chemotherapy. Here, we describe the design and synthesis of a novel copper(II) indenoisoquinoline complex, WN198. The new organometallic compound exhibits a cytotoxic effect on five adenocarcinoma cell lines (MCF-7, MDA-MB-231, HeLa, HT-29, and DU-145) with the lowest IC50 (0.37 ± 0.04 μM) for the triple-negative MDA-MB-231 breast cancer cell line. Below 5 µM, WN198 was ineffective on non-tumorigenic epithelial breast MCF-10A cells and Xenopus oocyte G2/M transition or embryonic development. Moreover, cancer cell lines showed autophagy markers including Beclin-1 accumulation and LC3-II formation. The DNA interaction of this new compound was evaluated and the dose-dependent topoisomerase I activity starting at 1 μM was confirmed using in vitro tests and has intercalation properties into DNA shown by melting curves and fluorescence measurements. Molecular modeling showed that the main interaction occurs with the aromatic ring but copper stabilizes the molecule before binding and so can putatively increase the potency as well. In this way, copper-derived indenoisoquinoline topoisomerase I inhibitor WN198 is a promising antitumorigenic agent for the development of future DNA-damaging treatments. [ABSTRACT FROM AUTHOR]

Water oxidation reaction (WOR) is a rather sluggish process in the water splitting that hampers the extraction of hydrogen gas from water in a large scale. It is highly desirable to develop low‐cost WOR catalysts to increase the efficacy. Herein two Cu(II) complexes [Cu (DTEL)2]n(ClO4)2n (1) and [Cu(DTE)2(ClO4)2] (2) of two triazolylpyridines, 1‐(2‐hydroxy)‐4‐(2‐pyridyl)1,2,3‐triazole (DTEL) and 1‐(2‐acetoxymethyl)‐4‐(2‐pyridyl)1,2,3‐triazole (DTE), have been synthesized and characterized. The X‐ray diffraction analysis revealed that the copper centers of 1 and 2 adopted the octahedral coordination geometry with four N atoms from two DTEL or DTE ligands in the equatorial plane. The two axial sites were weakly ligated by the hydroxyl group of DTEL or perchlorate. Both complexes 1 and 2 were homogenous molecular catalysts boosting the WOR in pH 9.0 phosphate buffer solution with the overpotentials being 568 and 478 mV, rate constants (kcat) of 0.1 and 0.39 s−1, and Faradaic efficiencies of 90% and 93%, respectively. The pendant substituent on the two triazolylpyridine ligands DTEL and DTE apparently influenced the catalysis. A mechanism for the catalytic WOR mediated by 1 and 2 was suggested on the basis of the experimental data. This work illustrated that triazolylpyridines were promising scaffolds for forming metal complexes working as WOR catalysts. [ABSTRACT FROM AUTHOR]

The title compound, bis[μ-3-ethyl-5-(pyridin-2-yl)-1H-1,2,4-triazol-1-ido]bis[acetato(dimethylformamide)copper(II)], [Cu2(C9H9N4)2(C2H3O2)2(C3H7NO)2] or [Cu2(LEt)2(OAc)2(dmf)2], is a triazolate complex, which contains two 3-(2-pyridyl)-5-ethyl-triazolates (LEt)− in bidentate-bridged coordination modes. Both copper atoms are involved in the formation of a planar six-membered metallocycle Cu–[N—N]2–Cu. The inversion center of the complex is located at the mid-point of the Cu...Cu vector. Each CuII atom has a distorted trigonal–bipyramidal environment formed by the three nitrogen atoms of the deprotonated bridging 3-(2-pyridyl)-5-ethyl-triazolate unit, oxygen atoms of the OAc− group and dmf molecule. In the crystal, C—H...O hydrogen bonds link the molecules into chains running along the c-axis direction.

The dark-red title complex crystallized from an equimolar methanol solution of (E)-5-(ethylamino)-4-methyl-2-[(pyridin-2-yl)diazenyl]phenol and CuCl2(phen) (phen = 1,10-phenanthroline) as a centrosymmetric dimer, [CuCl(C14H15N4O)]2. The Cu atoms are bridged by two Cl ligands and have a slightly distorted square-pyramidal coordination, where two N atoms from the azo and the pyridine moieties, a phenolic O and a Cl atom comprise the base and the other Cl occupies the apex position. The apical Cu—Cl bond, 2.6192 (4) Å, is longer than the basal one, 2.2985 (3) Å, due to Jahn–Teller distortion. The dimers are associated via weak intermolecular hydrogen bonds and π–π stacking interactions between phenyl and pyridine rings. A monomeric by-product of the same reaction, [CuCl(phen)2]Cl·4H2O, has a trigonal–bipyramidal coordination of Cu with equatorial Cl ligand, and extensive outer-sphere disorder. In the structure of 4, the packing of cations leaves continuous channels containing disordered Cl− anions and solvent molecules. The identity of the solvent (water or a water/methanol mixture) was not certain. The disordered anion/solvent regions comprise 28% of the unit-cell volume. The disorder was approximated by five partly occupied positions of the Cl− anion and ten positions of O atoms with a total occupancy of 3, giving a total of 48 electrons per asymmetric unit, in agreement with the integral electron density of 47.8 electrons in the disordered region, as was estimated using the BYPASS-type solvent-masking program [van der Sluis & Spek (1990). Acta Cryst. A46, 194–201].

This work involved the successful synthesis of three new Schiff base complexes, including Ni(II), Mn(II), and Cu(II) complexes. The Schiff base ligand was created by reacting the malonyldihydrazide molecule with naphthaldehyde, and the final step involved reacting the ligand with the corresponding metallic chloride yielding pure target complexes. FTIR, 1 H NMR, 13 C NMR, mass, and UV/Vis spectroscopies were used to comprehensively characterize the produced complexes. These substances have been employed in this study to photo-stabilize polystyrene (PS) and lessen the photo-degradation of its polymeric chains. Several methods, including FTIR, weight loss, viscosity average molecular weight, light and atomic force microscopy, and energy dispersive X-ray (EDX) mapping, were used to assess the effectiveness of produced complexes as photo-stabilizers. These experiments supported one another and showed how well novel complexes stabilize PS photos. Hence, after 300 h of exposure to UV light with a wavelength of 313 nm, they lessen the photo-degradation of PS films containing these complexes compared to blank PS. Also, it has shown that the copper(II) complex works well as a photo-stabilizer. This is due to the highly conjugated systems in these compounds. The findings of this study have significant implications for reducing PS usage globally, which poses a serious danger to the environment, particularly the marine eco-system as a result of plastic trash. [ABSTRACT FROM AUTHOR]

A μ-chlorido-bridged tetra-nuclear copper(II) complex containing 2,3,5,6-tetra(2-pyridyl)pyrazine (tppz), chlorido, and perchlorato ligands, starting from 2-aminomethyl pyridine (AMP) and Cu(OAc)2·H2O, was synthesized. The structure of the complex was determined by single-crystal X-ray diffraction (SCXRD), Fourier transform infrared spectroscopy (FT-IR), and electronic absorption spectroscopy (UV–Vis). The redox behavior of the complex was explored by cyclic voltammetry. The tetra-nuclear structure is formed by combining the di-nuclear copper complex of the two tppz ligands with a chloride bridge. The Cu(1) center adopts a distorted octahedral geometry, whereas the other three Cu centers adopt square pyramid geometries. Crystal data of the complex are monoclinic, P21/c, a = 13.602(4) Å, b = 13.438(4) Å, c = 29.412(8) Å, α = 90°, β = 95.258(8)°, γ = 90°, V = 5353(3) Å3, Z = 4. When the SCXRD structure was examined, it was determined that the two central pyrazine rings deviated from planarity, which is one of the four criteria for aromaticity. The aromaticity of the central pyrazine rings, whose planarity is disturbed, is decreased. Based on these bond lengths, the harmonic oscillator aromaticity model (HOMA) values of the non-planar central pyrazine rings were calculated as 0.964926 and 0.942886, respectively. [ABSTRACT FROM AUTHOR]

Reaction of 3-aminobenzenesulfonic acid (HL1) with Cu(NO3)2·2.5H2O in H2O/DMF leads to the formation of the new bis(3-aminobenzenesulfonato-κN)-diaqua-bis(dimethylformamide-κO)-copper(II) complex [Cu(L1)2(DMF)2(H2O)2] (1) (HL1 = 3-aminobenzenesulfonic acid and DMF = N,N-dimethylformamide). Single crystal X-ray analysis reveals that the hexacoordinated copper(II) center adopts a distorted octahedral geometry with trans-oriented two 3-aminobenzenesulfonate ligands (L1−), two water and two dimethylformamide (DMF) molecules. Comparison of its crystal structure with that of the known bis(4-aminobenzenesulfonato-κN)diaquabis(dimethylformamide-κO)-copper(II) complex [Cu(L2)2(DMF)2(H2O)2] (2) (HL2 = 4-aminobenzenesulfonic acid) discloses that 1 and 2 are the isomers with an identical empirical formula (C18H30CuN4O10S2) and equal numbers of same coordinated solvents (DMF and water). H-bonded supramolecular structures and their corresponding topological analyses revealed a 2D with 6-connected hxl/Shubnikov plane net (3,6) for 1 and a 3D with 8-connected bcu; 8/4/c1; sqc3 net for 2, which are completely different. [ABSTRACT FROM AUTHOR]

Barium–copper(II) and barium–iron(III) coordination polymers with malonic acid dianions [BaCuII(Mal)2(H2O)4]n (1) (CCDC No. 2239603) and (2) (CCDC No. 2239902) are prepared for the first time. The complexes are built by bischelate fragments of 3d metals {M(Mal)2}x– (x = 2 for 1, x = 1 for 2) forming layers (1) or fragments coupled by OH bridges (2) in the crystal. The barium atoms coordinate O atoms of chelate-bridging malonate anions and bridging water molecules that are additionally H-bonded to the {M(Mal)2}x– fragments in 1 and 2, thus forming complex Ba–O–H...{M(Mal)2} bridges suitable for the formation of 3D and 2D polymers, respectively. The new compounds are characterized by single-crystal XRD, IR spectroscopy, CHN analysis, and powder XRD methods. [ABSTRACT FROM AUTHOR]

Two new copper(II) complexes of bidentate arylhydrazone ligands have prepared and studied. Elemental analysis, SEM-EDS, thermal gravimetric analysis (TGA), powder X-ray diffraction (XRD), and a number of spectroscopic techniques were used to determine the structures of the compounds (FTIR, UV-Vis, 1H and 13C-NMR). Using agarose gel electrophoresis, the DNA cleavage activities of the produced copper complexes were investigated in the absence and presence of hydrogen peroxide. It was also investigated the influence of compound dose on the DNA cleavage process. The results show that in the presence of an oxidant agent, all of the complexes break pBR322 DNA. At the concentration of 10 µM, [Cu(L1)2] converted the supercoil DNA into two forms, while [Cu(L1)2] formed only the nicked form. The mechanistic analyses show that the active oxidative species for DNA breakage is a species generated by hydrogen peroxide and the copper(II) metal. The compounds also cleaveged pBR322 DNA in the absence of H2O2, marginally.

In the title dinuclear CuII complex, [Cu2(NO3)(C24H46N8)(H2O)](NO3)3·3H2O, the two CuII molecules both have a square-pyramidal geometry, but the ligands in the axial positions are different: a water molecule and a nitrate ion. All nitrate ions, water molecules, and N—H groups are involved in an intermolecular hydrogen-bond network.

Cu(II) complexes of substituted Guanidines having common formula [κ2(O, N)-C6H5CONHC(NHR1)NR2]2Cu(II), in which R1 = C6H5– and R2 = C(CH3)3 (1), CH2CH2CH3 (2), CH(CH3)2 (3), 2, 6-Cl2C6H3 (4) and 4-CH3C6H4 (5) were synthesized and their structural and chemical characteristics were examined by CHN analyzer, FTIR, NMR Spectrometer (including 1H and 13C) and magnetic susceptibility balance. Two of the guanidine ligands and their Cu(II) complexes were also analyzed by single crystal X-ray diffraction. The X-ray diffraction analysis revealed that majority of the studied guanidine ligands were stable due to intermolecular and intra-molecular hydrogen bonding. The synthesized compounds are mononuclear having pseudo square planar geometry, whereas guanidine ligands attached to the metal center via oxygen and nitrogen atoms. The metallodrugs demonstrated better urease inhibition action than their parent guanidine ligands and also have shown fairly good score regarding the potato disk bioassay in comparison with the vincristine, employed as a standard drug. [ABSTRACT FROM AUTHOR]

New Cu(II) and Co(II) complexes with the N-{2-[(E)-(4-cyclohexylphenyl)iminomethyl]phenyl}-4-methylbenzene-1-sulfonamide Schiff base are prepared and characterized by 1H NMR, IR spectroscopy, and elemental analysis. The crystal structure of azomethine and its complexes is studied by XRD. The obtained XRD data show that two N,N-bidentate ligands are chelated to Cu(II) and Co(II) ions in both complexes and form a distorted tetrahedral environment of four nitrogen atoms around the ions. [ABSTRACT FROM AUTHOR]

Two distorted octahedral copper(II) coordination compounds; [Cu(AMPp)2(OClO3)2] (1) and [Cu(AMP)2(OClO3)2] (2) (2-aminomethylpiperidine and 2-aminomethylpyridine) have been synthesized on a SP Sephadex C-25 cation exchanger resin for high purity. Their structures have been determined by single-crystal X-ray diffraction, fourier transform infrared spectroscopy, and also thermal analysis. In both structures, the metal center adopts an elongated octahedral geometry in which two chelating amine ligands occupy the square plane in a trans-position, and two perchlorate ligands occupy the axial sites. The thermal stability of both complexes is relatively high. However, the thermal stability of 2 with the aromatic ring was 12 °C higher, due to intermolecular hydrogen bonds, π⋯π, and π⋯O interactions. [ABSTRACT FROM AUTHOR]

The title compound, bis[μ-3-ethyl-5-(pyridin-2-yl)-1H-1,2,4-triazol-1-ido]bis-[acetato(dimethylformamide)copper(II)], [Cu2(C9H9N4)2(C2H3O2)2(C3H7NO)2] or [Cu2(LEt)2(OAc)2(dmf)2], is a triazolate complex, which contains two 3-(2-pyridyl)-5-ethyl-triazolates (LEt)- in bidentate-bridged coordination modes. Both copper atoms are involved in the formation of a planar six-membered metallocycle Cu-[N-N]2-Cu. The inversion center of the complex is located at the mid-point of the Cu...Cu vector. Each CuII atom has a distorted trigonal-bipyramidal environment formed by the three nitrogen atoms of the deprotonated bridging 3-(2-pyridyl)-5-ethyl-triazolate unit, oxygen atoms of the OAc- group and dmf molecule. In the crystal, C-H...O hydrogen bonds link the molecules into chains running along the c-axis direction. [ABSTRACT FROM AUTHOR]

A new copper(II) complex [Cu(3,5,6-tcpa)(2,2′-bipy)Cl] (1) has been obtained through the one-pot hydrothermal reaction of copper chloride dihydrate with triclopyr (systematic name 2-((3,5,6-trichloropyridin-2-yl)oxy)acetic acid, abbreviation 3,5,6-Htcpa) and 2,2′-bipyridine (2,2′-bipy) coligands. 1 has crystallized in triclinic crystal system, P 1 ‾ space group. The central copper(II) ion displayed a distorted square–pyramidal geometry and was connected by one chlorido co-ligand (Clˉ), one 3,5,6-tcpa anionic chelator and one chelating 2,2'-bipy ligand to afford a mononuclear structure. 1 is further extended into a 3D network by the non-covalent interactions of H⋯Cl, H⋯O hydrogen bonds, aromatic π⋯π stacking together with Cl⋯Cl halogen bond interactions. The co-crystallization process, the crystal structure of 1 as well as the Hirshfeld surface analysis for 1 have been analyzed and described. In addition, the flexible conformation of phenoxy methylene group among 1, triclopyr acid and its previously reported co-crystallized compound also have been carefully compared and discussed. [ABSTRACT FROM AUTHOR]

Herein, the synthesis, structural characterization and in vitro biological evaluation of a novel Cu(II) complex with the 2-(4-aminophenyl)benzothiazole pharmacophore conjugated with the (2-pyridinyl)methylamino chelating moiety is reported for the first time. A full characterization of the Cu(II) complex was conducted by X-ray crystallography, EPR, IR, elemental and MS analysis, and its binding to CT-DNA was investigated by UV-vis spectroscopy, ethidium bromide competition studies, circular dichroism, viscometry and thermal denaturation. The data clearly indicate that the Cu(II) complex interacts with CT-DNA via intercalation, registering a difference compared to previously reported Pt(II) and Pd(II) analogues. To evaluate the anticancer activity of the complex, a series of in vitro experiments against breast, glioblastoma, prostate and lung cancer cell lines along with healthy fibroblasts were implemented. Cytotoxicity, cellular uptake, intracellular ROS production, cell cycle and apoptosis analysis revealed an increased anticancer activity towards breast cancer cells that is accompanied by an induction in intracellular ROS levels and a significant G2/M arrest followed by apoptosis. [ABSTRACT FROM AUTHOR]

The reaction between copper(II) chloride dihydrate and the (E)-2-methyl-4-(quinolin-8-yldiazenyl)benzene-1,3-diol ligand in acetonitrile leads to the formation of the title compound, [Cu(C16H12N3O2)Cl]·H2O. The ligand is deprotonated and coordinates with three donor atoms (tridentate) to the CuII ion. Individual molecules of the CuII complex are connected by chloride bridges, forming a one-dimensional coordination polymer. No photoisomerization to the cis isomer of the azo ligand was observed upon irradiation with UV light.

The effect of the Na4[CuN(CH2PO3)3]·13H2O complex compound with a chelate structure on the corrosion-electrochemical behavior of 20# steel in a borate buffer solution at pH 7.4 and natural aeration was studied using the potentiodynamic method and methods of X-ray photoelectron spectroscopy and surface scanning electron microscopy with microanalysis. It was established that in the concentration range of 0.2–1.0 mM the complex under study inhibits the anodic dissolution of the metal and drives it at higher concentrations. In terms of its effect on the corrosion-electrochemical behavior of steel, the Na4[CuN(CH2PO3)3]·13H2O complex differs significantly from the previously studied complexes Na4[ZnN(CH2PO3)3]·13H2O and Na4[Cd(H2O)N(CH2PO3)3]·7H2O. In the potential range –0.66...–0.05 V relative to the Ag,AgCl|KCl-electrode (SSCE) a layer of metallic copper is generated on the surface in the form of nano-sized crystals, shielding the surface of the steel. In the potential range of 0.05–0.13 V (SSCE), metallic copper is oxidized, and with a further increase in the potential, a layer of mixed iron and copper oxides is formed. [ABSTRACT FROM AUTHOR]

The dark-red title complex crystallized from an equimolar methanol solution of (E)-5-(ethyl­amino)-4-methyl-2-[(pyridin-2-yl)diazen­yl]phenol and CuCl2(phen) (phen = 1,10-phenanthroline) as a centrosymmetric dimer, [CuCl(C14H15N4O)]2. The Cu atoms are bridged by two Cl ligands and have a slightly distorted square-pyramidal coordination, where two N atoms from the azo and the pyridine moieties, a phenolic O and a Cl atom comprise the base and the other Cl occupies the apex position. The apical Cu--Cl bond, 2.6192 (4) Å, is longer than the basal one, 2.2985 (3) Å, due to Jahn-Teller distortion. The dimers are associated via weak inter­molecular hydrogen bonds and π-π stacking inter­actions between phenyl and pyridine rings. A monomeric by-product of the same reaction, [CuCl(phen)2]Cl·4H2O, has a trigonal-bipyramidal coordination of Cu with equatorial Cl ligand, and extensive outer-sphere disorder. In the structure of 4, the packing of cations leaves continuous channels containing disordered Cl-anions and solvent mol­ecules. The identity of the solvent (water or a water/methanol mixture) was not certain. The disordered anion/solvent regions comprise 28% of the unit-cell volume. The disorder was approximated by five partly occupied positions of the Cl- anion and ten positions of O atoms with a total occupancy of 3, giving a total of 48 electrons per asymmetric unit, in agreement with the integral electron density of 47.8 electrons in the disordered region, as was estimated using the BYPASS-type solvent-masking program [van der Sluis & Spek (1990). Acta Cryst. A46, 194-201]. [ABSTRACT FROM AUTHOR]

Three new copper(II) 5,5-diethylbarbiturate (barb) complexes of nicotinamide (nia), 2,2′-bipyridine (bpy) and triethanolamine (tea), trans-[Cu(barb)2(nia)2]⋅2H2O (1), cis-[Cu(barb)2(bpy)]⋅3H2O (2) and [Cu2(barb)2(tea)2]⋅2H2O (3), were synthesized and characterized by elemental analysis, spectroscopic (UV-Vis and FTIR) and magnetic moment measurements. Single crystal X-ray crystallographic measurements showed that 1 and 2 are mononuclear, while 3 is binuclear, in which two copper centers were bridged by deprotonated ethanol groups of two tea ligands. The barb ligand in these complexes is a bidentate N, O-donor. Thermal analysis (TG/DTA) studies in air indicated that the complexes first dehydrated and then the decomposition of nia, bpy or tea ligands occurred. The last exothermic stage was associated with degradation of the barb moiety to yield CuO as the end product. [ABSTRACT FROM AUTHOR]

The ascidian species Lissoclinum patella is found, amongst other places, around Heron Island on the Great Barrier Reef, Australia. L. patella has a cyanobacterial symbiont, Prochloron didemni , known to produce various cyclic peptides, including quantities of the cyclic pseudo-octapeptides, the patellamides. Patellamides are of pharmaceutical interest and have attracted the curiosity of coordination chemists because they can form quite stable mono- and di-nuclear transition metal complexes, particularly with copper(ii). For some patellamide derivatives, the binding of two CuII centres is cooperative and solution equilibria involving metal-free peptides, mono- and di-nuclear copper(ii) complexes, and various functions of these complexes have been described. These studies were also driven by the observation that the ascidians possess copper concentrations in excess of that in the seawater around Heron Island, and accumulation factors of approximately 104 have repeatedly been reported. New data presented here, based on inductively coupled plasma atomic emission spectroscopy (ICP-OES) and ICP-mass spectromety (MS) measurements, indicate that the 104 factor is overestimated and a factor >500 and up to approximately 3000 is more realistic. There are large quantities of cyclic peptides in Lissoclinum patella ascidians, produced by the obligate symbiont Prochloron. Ascidians accumulate copper but the generally assumed factor of 104 is much overestimated, and it is shown here that there is a significant accumulation factor >500 and up to approximately 3000. [ABSTRACT FROM AUTHOR]