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Self-assembly of M(ClO4)2 (M(II) = Mn(II), Co(II), Ni(II), Cu(II), and Zn(II)) with dicyclopentyldi(pyridine-3-yl)silane (L) as a donor in a mixture of acetonitrile and toluene produces crystals consisting of M6L12 double-stranded macrocycles. The geometry around the M(II) cations is a typical octahedral arrangement, but the metallamacrocycles' outer axial coordination environment is sensitive to the M(II) cations. The conformation of the unique metallamacrocycles is informatively dependent on the nature of the coordination around the M(II) cations via subtle co-ligand competition among perchlorate anions, water, and acetonitrile. Both the coordinated acetonitriles and the solvate molecules of the crystals are removed at 170 °C, thereby transforming the crystals into new crystals that return to their original form in the mixture of toluene and acetonitrile. Catalytic oxidation of 3,5-di-tert-butylcatechol using [Cu6(ClO4)8(CH3CN)4L12]4ClO4·5C7H8 is much faster than those using the transformed product, [Cu(ClO4)2L2], and a simple mixture of Cu(ClO4)2 + L. [ABSTRACT FROM AUTHOR]

Herein, we present a dark-green crystalline tetranuclear Cu(II) Schiff base complex {C1 = [Cu4L4](ClO4)4(DMF)4(H2O)} using a N,N,O donor ligand (HL), namely 2-(((2-hydroxypropyl)imino)methyl)-6-methoxyphenol. Spectro-photometrical investigation on the β-lactamase-like activity of this coordinately saturated system revealed its catalytic inefficiency towards hydrolysis of nitrocefin as a model substrate. This complex has attracted significant interest as a promising photo-catalyst owing to its narrow band gap (2.40 eV) as predicted from DFT calculations and its higher responsivity towards UV light. Therefore, C1 is effectively involved in the photocatalytic reduction of perchlorate to Cl− in the presence of a hole scavenger (H2O–MeOH) under prolonged UV irradiation and itself becomes photo-cleaved to yield a new dark-brown colored chlorobridged dinuclear crystalline complex C2 {[CuL(H2O)2Cl3]H2O}. Furthermore, C2 was deployed as a functional β-lactamase model and was found to show a remarkable catalytic proficiency towards the hydrolysis of nitrocefin in 70 : 30 (V/V) MeOH–H2O medium. This pro-catalyst C2 has been speculated to generate an aqua bridged active catalyst that plays a crucial factor in hydrolysis. This phenomenon was again experimentally established by potentiometric pH titration where C2 displays only one pKa value (7.11) in the basic pH range, indicating the deprotonation of the bridged water molecule. Based on several other kinetic studies, it may be postulated that the hydrolysis of nitrocefin is initiated by the nucleophilic attack of a bridging hydroxide, followed by very fast protonation of the intermediate to furnish the hydrolyzed product. It is noteworthy that the rate of nitrocefin hydrolysis is greatly inhibited in the presence of external chloride concentration. To the best of our knowledge, this is the first report on the photochemical behavior of such a tetranuclear copper(II) Schiff base complex. Our current interest is focused on inventing a potent β-lactamase inhibitory therapeutic as well as elucidating its mechanism through comprehensive chemical analysis. [ABSTRACT FROM AUTHOR]

Neutral Cu(I) complexes containing Schiff bases as chelating N‐donors and phosphines as P‐donors were efficiently isolated and characterized. The imines were obtained by straightforward condensation between pyrrole‐2‐carboxaldehyde and the corresponding aromatic amines. The structure of most of the Cu(I) species was elucidated through single‐crystal X‐ray diffraction. The Cu(I) complexes exhibited intense absorptions around 400–500 nm ascribed to MLCT transitions. For some Cu(I) derivatives, orange‐ and red‐orange emissions were detected upon excitation with near‐UV and blue irradiation in the solid state. The emission maxima were red‐shifted once the benzothiazole‐derived Schiff base or Xantphos were employed as chelating ligands. Microsecond‐long lifetimes, wide emissions, and large Stokes shifts suggest the involvement of triplet states in the luminescent process. Electrochemical measurements and DFT calculations were employed to rationalize the photoluminescence properties, which were ascribed to mixed 3LC/3MLCT transitions. [ABSTRACT FROM AUTHOR]

Two new transition metal complexes of a dipyrazinylpyridine (dppy) ligand 3,4-diethoxyphenyl-2,6-di(pyrazine-2-yl)pyridine L, {[CuL2]Cl2 (1) and [ZnL2]Cl2 (2)}, have been synthesized and characterized using NMR (for L and 2), UV-vis spectroscopy, ESR (for 1), HRMS, elemental analysis and DFT study. Upon interaction with bovine serum albumin (BSA), complexes 1 and 2 demonstrated varying binding capabilities, with 1 displaying superior binding (binding constant 4.5 x 104 M-1) towards BSA than 2 (binding constant 1.2 x 104 M-1). Similarly, with calf-thymus DNA (ct-DNA), 1 showed better binding affinity (1.1 x 106 M-1) than 2 (8.5 x 105 M-1) as observed from UV-visible spectroscopy. The mechanism that leads to the quenching of BSA fluorescence by 1 and 2 is attributed to static quenching. The complexes demonstrated an intercalative binding mode with ct-DNA, and molecular docking has been employed to elucidate the biomolecular interactions with the complexes. Circular dichroism spectra have been utilized to confirm the binding and assessment of the interactions with the biomolecules. Furthermore, studies of the anticancer potentials of 1-2 were evaluated using the Dalton's lymphoma (DL) cancer cell line. Following 48 hours of treatment, the IC50 values for 1 and 2 were identified as 24 mM and 28 mM, respectively, indicating their potency in inhibiting cancer cell growth. [ABSTRACT FROM AUTHOR]

A tridentate pyrazolone‐furan Schiff's base ligand, [(E)‐4‐(((5‐[2‐fluorophenyl]furan‐2‐yl)methylene)amino)‐1,5‐dimethyl‐2‐phenyl‐1,2‐dihydro‐3H‐pyrazol‐3‐one] (PFSB), was produced by condensation between compounds 5‐(2‐fluorophenyl)furan‐2‐carbaldehyde and 4‐amino‐1,5‐dimethyl‐2‐phenyl‐1,2‐dihydro‐3H‐pyrazol‐3‐one. Spectroscopic characterization evidence suggested the tridentate nature (ONO) of pyrazolone‐furan Schiff's base ligand (PFSB) and coordinated to the metal (II/III) moieties through nitrogen and oxygen donor sites giving tetra‐ and/or hexa‐coordinated geometry to complexes. The complexes have been supported by elemental analyses, molar conductance, magnetic moments, spectral analyses, EPR, ligand field parameters, XRD, and thermogravimetric measurements. Theoretical optimization employing the density functional theory (DFT) was accomplished on the molecular structures of the compounds in question, and subsequently, the quantum chemical descriptors were computed. Cr(III), Co(II), Ni(II), and Zn(II) complexes were allocated octahedral coordination, while the Cu(II) complex was allocated square‐planar coordination. The SEM, TEM, XRD, AFM, and EDX of the studied complexes unveiled distinct and strong diffraction peaks, signifying their crystalline nature, and providing evidence of their particle sizes being within the nano‐size. The crystal sizes calculated for all complexes were determined to be ranging from 27.73 to 76.39 nm. However, the Cr(III) complex exhibited a particle size exceeding 100 nm. The interactions between metal complexes and calf thymus DNA, and their potential for mimicking insulin activity, were investigated in a controlled lab setting by measuring their ability to inhibit alpha‐amylase. The anti‐microbial potential of the ligand (PFSB) and complexes (C1‐C5) were tested. The viscosity and UV–Vis absorption determinations were utilized to assess the calf thymus DNA (CT‐DNA) interaction with the nano‐sized metal (II/III) chelates. Our flow cytometry data indicate significant levels of apoptosis and cell cycle arresting in both liver and breast cancer cell lines. [ABSTRACT FROM AUTHOR]

Novel divalent chelates of Co (II), Cu (II), Zn (II) and Ni (II) were prepared and described of the form [M (NTM)(CH3COO)2] where NTM = [1‐(4‐nitrophenyl)‐1H‐1,2,3‐triazol‐4‐yl)methanol ligand. Elemental analyses, infrared red, 1H and 13CNMR, electronic, magnetic susceptibility, conductivity measurements and X‐ray diffraction studies were used to assess our divalent metal complexes. Moreover, the stability and stoichiometry of the novel metal chelates were examined through the job's method in solutions. Correlation of all spectroscopic techniques states that NTM acts as a bi‐dentate NO ligand to afford octahedral complex geometry for all the investigated metal chelates. Thermodynamic and kinetics factors for various thermal degradation phases were calculated. Moreover, B3LYP/LANL2DZ/6‐311 g(d,p) theoretical study has been applied for estimating the MEP and quantum chemical reactivity descriptors of studied molecules. Moreover, the UV–Vis absorption spectra for the investigated molecules are predicted via the time‐dependent DFT (TD‐DFT) calculations. In addition, MOE‐ docking was tested on two different proteins, the receptor of (3HB5) breast cancer mutant oxidoreductase as well as the receptor of Glucosamine‐6‐phosphate synthase in complex with glucosamine‐6‐ phosphate of (2VF5) E.coli and COVID‐19 protease. The results recommended that the (NTMCo), (NTMNi), (NTMCu) and (NTMZn) complexes showed the highest inhibitory activity compared to the other NTM ligands as antimicrobial and breast cancer candidates. Furthermore, in‐vitro anti‐bacterial, anti‐fungal, cytotoxic and anti‐oxidant performances for the selected ligand as well as its chelates were studied. All metal chelates presented superiority, proceeding free organic ligand ineffective management, definitely NTMCu complex. [ABSTRACT FROM AUTHOR]

A new copper (II) complex containing the mono basic ligand (HL) azo naringenin was synthesized and structurally characterized by analytical, magnetic, and various spectroscopic techniques. An octahedron geometry was proposed for the assigned molecular formula [Cu(L)(CH3COO)(OH2)2]. Processing of powder X‐ray diffraction data for the copper (II) complex in question by the Expo 2014 computer program confirmed the proposed structure inferred from the spectroscopic studies. The DNA binding ability of the free ligand and its copper (II) complex was tested, and the results obtained demonstrated the stronger DNA binding ability of the copper (II) complex over the azo naringenin ligand. The antioxidant potency of copper (II) complex was investigated via the DPPH free radical‐scavenging assay. The present azo naringenin ligand and its copper (II) complex have shown diverse biological potentials including antitumor, antifungal, and antibacterial activities. [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]

Three new coordination polymers (CPs), {[Cu(NDC)(Fbtx)(H2O)] ⋅ 1.5H2O}n (1), {[Co(NDC)(Fbtx)(H2O)2] ⋅ 0.5Fbtx}n (2), and [Co2(NDC)2(Fbtx)]n (3), were synthesized by employing acid‐base mixed ligands of rigid 1,4‐naphthalenedicarboxylic acid (H2NDC) and flexible bis(1,2,4‐triazole‐1‐ylmethyl)‐2,3,5,6‐tetrafluorobenzene (Fbtx) under both hydrothermal and microwave‐assisted reaction conditions. Single‐crystal structure analysis establishted that both compounds 1 and 2 exhibit two‐dimensional (2D) layered structures, while compound 3 features a three‐dimensional (3D) complicated framework. The geometries of metal ions vary from square pyramidal (in 1 and 3) to distorted octahedral (in 2). Topological strudy showed that compounds 1 and 2 have exposed common 4‐connected 44‐sql net, while compound 3 has made a novel 4,5‐connected net with point symbol of (43 ⋅ 62 ⋅ 7)(43 ⋅ 64 ⋅ 72 ⋅ 8). The catalytic performance of the three complexes for the solvent‐free ring‐opening polymerization of L‐lactide has been investigated. The results indicated that compound 3 with coordinatively unsaturated cobalt(II) sites showed good activity and the molecular weight of the polymer obtained was high. Moreover, the complex 3 catalyst could be recycled up to five times with the retention of both catalytic activity and crystal structure. [ABSTRACT FROM AUTHOR]

Two new copper(II) complexes (1 and 2) with reduced L -histidine Schiff bases were synthesized and characterized using single-crystal X-ray diffraction, powder X-ray diffraction, UV-visible spectroscopy, and thermal analysis. Single-crystal analysis reveals that 5-methyl-containing 1 possesses a simple phenoxo-bridged binuclear unit, while 5-bromine-substituted 2 possesses a metal–organic cage (MOC) structure. The as-prepared complexes as artificial metallohydrolases displayed catalytic activity towards the hydrolysis of both PNPP (p-nitrophenyl picolinate) and PNPA (p-nitrophenyl acetate). These two complexes provided 28-fold (for 1) and 39-fold (for 2) rate enhancements in comparison with spontaneous hydrolysis of PNPA, respectively. With regard to PNPP, its hydrolysis was accelerated by two orders of magnitude in the presence of 1 or 2. Additionally, positive micellar effects of bis(hexadecyldimethylammonium)hexane bromide (16-6-16) and N-octyldocosylammonium bromide (C22H45N(CH3)2C8H17Br, abbr. C22/8) were observed for the PNPA hydrolysis by 1 or 2, resulting in 1.3 to 3.9 times acceleration compared to that in buffered aqueous solution. In micellar solution of N,N-dimethyl-n-lauroylsarcosine sodium (LSS), no obvious rate enhancement was observed for the PNPA hydrolysis by 1 or 2. [ABSTRACT FROM AUTHOR]

The interactions with calf thymus DNA (CT-DNA) of three Schiff bases formed by the condensation of hesperetin with benzohydrazide (HHSB or L1H3), isoniazid (HIN or L2H3), or thiosemicarbazide (HTSC or L3H3) and their CuII complexes (CuHHSB, CuHIN, and CuHTSC with the general formula [CuLnH2(AcO)]) were evaluated in aqueous solution both experimentally and theoretically. UV–Vis studies indicate that the ligands and complexes exhibit hypochromism, which suggests helical ordering in the DNA helix. The intrinsic binding constants (Kb) of the Cu compounds with CT-DNA, in the range (2.3–9.2) × 106, from CuHTSC to CuHHSB, were higher than other copper-based potential drugs, suggesting that π–π stacking interaction due to the presence of the aromatic rings favors the binding. Thiazole orange (TO) assays confirmed that ligands and Cu complexes displace TO from the DNA binding site, quenching the fluorescence emission. DFT calculations allow for an assessment of the equilibrium between [Cu(LnH2)(AcO)] and [Cu(LnH2)(H2O)]+, the tautomer that binds CuII, amido (am) and not imido (im), and the coordination mode of HTSC (O−, N, S), instead of (O−, N, NH2). The docking studies indicate that the intercalative is preferred over the minor groove binding to CT-DNA with the order [Cu(L1H2am)(AcO)] > [Cu(L2H2am)(AcO)] ≈ TO ≈ L1H3 > [Cu(L3H2am)(AcO)], in line with the experimental Kb constants, obtained from the UV–Vis spectroscopy. Moreover, dockings predict that the binding strength of [Cu(L1H2am)(AcO)] is larger than [Cu(L1H2am)(H2O)]+. Overall, the results suggest that when different enantiomers, tautomers, and donor sets are possible for a metal complex, a computational approach should be recommended to predict the type and strength of binding to DNA and, in general, to macromolecules. [ABSTRACT FROM AUTHOR]

This study investigates the influence of ligand charge on transition energies in a series of CuN2S2 complexes based on dithiocarbazate Schiff base ligands using Cu K-edge X-ray absorption spectroscopy (XAS) and Kβ valence-to-core (VtC) X-ray emission spectroscopy (XES). By comparing the formally Cu(II) complexes [CuII(HL1)] (HL12− = dimethyl pentane-2,4-diylidenebis[carbonodithiohydrazonate]) and [CuII(HL2)] (HL22− = dibenzyl pentane-2,4-diylidenebis[carbonodithiohydrazonate]) and the formally Cu(III) complex [CuIII(L2)], distinct changes in transition energies are observed, primarily attributed to the metal oxidation state. Density functional theory (DFT) calculations demonstrate how an increased negative charge on the deprotonated L23− ligand stabilizes the Cu(III) center through enhanced charge donation, modulating the core transition energies. Overall, significant shifts to higher energies are noted upon metal oxidation, emphasizing the importance of scrutinizing ligand structure in XAS/VtC XES analysis. The data further support the redox-innocent role of the Schiff base ligands and underscore the criticality of ligand protonation levels in future spectroscopic studies, particularly for catalytic intermediates. The combined XAS-VtC XES methodology validates the Cu(III) oxidation state assignment while offering insights into ligand protonation effects on core-level spectroscopic transitions. [ABSTRACT FROM AUTHOR]

The magnetic properties of the trinuclear Schiff base complexes M2UL7 (MII=Co, Ni, Cu; L7=N,N'‐bis(3‐hydroxysalicylidene)‐2,2‐dimethyl‐1,3‐propanediamine), exhibiting the [M(μ‐O)2]2U core structure (3d‐5 f‐3d subsystem), have been investigated theoretically using scalar relativistic ZORA/DFT computations combined with the broken symmetry (BS) approach. The calculated coupling constants JMU between the adjacent M1−U and M2−U agree with the observed ferromagnetic (Ferro) character observed in the case of the Cu2UL7 complex, the antiferromagnetic (AF) character of the Ni2UL7 one is consistent with the experimentally observed AF behaviour for Co2UL7. The structural parameters, in particular the M−U distances and the M−Ob−U angles, as well as the electronic factors driving the superexchange couplings are discussed. The bond orders and the magnetic molecular orbital analyses reveal that the U(5 f) covalent contribution to the bonding within the M−O−U coordination is more important in the Co2UL7 and Ni2UL7 complexes than in the Cu2UL7 congener, thus favouring AF coupling between the transition metal and the uranium magnetic centers, in the first complexes. The analyses are supported by the study of the mixed ZnMUL7 and M2ThL7 systems, where the CoII (3d7) and NiII (3d8) paramagnetic ions are replaced by the diamagnetic ZnII(3d10) one, whereas in the second complex, the UIV(5f2) paramagnetic center is replaced by the diamagnetic ThIV(5f0) one. The Natural Populations Analyses confirm the crucial role of spin delocalization that is at work in favour of the AF vs. Ferro magnetic character of the M−U−M (M=Ni, Co) and Cu−U−Cu coordination, respectively. [ABSTRACT FROM AUTHOR]

The activation of molecular oxygen remains a persistent challenge to the scientific community owing to its poor selectivity, especially towards organic substrates. In biological systems, phenoxazinone synthase and catechol oxidase are two copper-based metalloenzymes that have been extensively studied because of their catalytic properties in the formation of a phenoxazinone core and quinones, which subsequently produce value-added compounds. Inspired by the design of a native catechol oxidase metalloenzyme, two copper(II) complexes (1 and 2) with dipicolylamine (DPA)-derived tridentate ligands L1 (4-methyl-N,N-bis(pyridin-2-ylmethyl)aniline) and L2 (2,4,6-trimethyl-N,N-bis(pyridin-2-ylmethyl)aniline) are synthesized. The tridentate ligands provided similar environmental facilities for attachment with three histidine moieties found in nature and our goal is to understand their biomimicking activity. On the amine nitrogen center, basicity is varied by systematic substitutions via methyl groups, thus affecting the bond strength of the apical chloride atom, which results in increased lability. The ligands were thoroughly characterized using different spectroscopic methods, i.e., FT-IR, 1H NMR, UV-vis spectroscopy, and ESI mass spectrometry. The molecular structures of 1 and 2 were elucidated using single-crystal X-ray diffraction, which confirms their distorted square pyramidal geometries with two distinct chlorines attached in a cis fashion. The investigation of their catalytic abilities was performed under ambient aerobic conditions in methanol with both o-aminophenol and 3,5-ditertbutyl catechol, which provided kinetic values that correlated with their structural modifications. Toluene-appended 1 (kcat 525 h−1 for o-aminophenol and 612 h−1 for 3,5-ditertbutyl catechol) showed almost twice the activities of mesitylene-derived 2 (kcat 255 h−1 for o-aminophenol and 343 h−1 for 3,5-ditertbutyl catechol). Mass spectroscopy supported their probable mechanisms for both substrates and confirmed the involvement of molecular oxygen in the reaction. EPR studies further confirmed radical generation during adduct formation in the case of catechol oxidation. This study offers detailed information regarding metal–ligand cooperation and their biomimicking activity, which directs the importance of designing suitable bioinspired catalysts. [ABSTRACT FROM AUTHOR]

This work focuses on the relationship between the coordination chemistry and antimicrobial activity of Zn (II) and Cu(II) complexes of histatin 5 and the products of its hydrolysis: its N-terminal fragment (histatin 5-8) and C-terminal fragment (histatin 8). Cu(II) coordinates in an albumin-like binding mode and Zn(II) binds to up to 3 His imidazoles. The antimicrobial activity of histatins and their metal complexes (i) strongly depends on pH - they are more active at pH 5.4 than at 7.4; (ii) the complexes and ligands alone are more effective in eradicating Gram-positive bacteria than the Gram-negative ones, and (iii) Zn(II) coordination is able to change the structure of the N-terminal region of histatin 5 (histatin 5-8) and moderately increase all of the studied histatins' antimicrobial potency. [ABSTRACT FROM AUTHOR]

In this work, a series of aldehyde‐substituted phthalocyanine compounds (1, 3, and 5) were prepared by the cyclotetramerization of the 4‐(5‐(diethylamino)‐2‐formylphenoxy) phthalonitrile (a) and the corresponding metal salts. Schiff base‐substituted phthalocyanines (2, 4, and 6) were derived from an aldehyde‐substituted phthalocyanine (1, 3, and 5) via the reaction of aldehyde‐substituted phthalocyanines with an amine reagent. The compounds that were obtained were characterized using FT‐IR, 1H {13C} NMR, UV–Vis, and MS spectra (a and 1–6). The inhibitory qualities of synthesized aldehyde and Schiff base‐substituted complexes against the enzymes butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) were assessed. The majority of phthalocyanines exhibited strong enzyme‐inhibiting properties. Out of the six produced phthalocyanines, 3 and 4 displayed the most intriguing profiles as submicromolar selective AChE inhibitors (IC50 = 0.060 μM), whereas 1 demonstrated the most potent BChE inhibitor (IC50 = 0.024 μM). The aggregation studies of CoPcs, CuPcs, and ZnPcs (1–6) were also carried out in this work. [ABSTRACT FROM AUTHOR]

Three novel ternary complexes [MII (PDA)(o‐phen)(H2O)] (MII = CoII, NiII, and CuII) were synthesized using 2,6‐pyridinedicarboxylicacid as a primary ligand and 1,10‐phenanthroline(o‐phen) as the auxiliary ligand and analyzed by FT‐IR, mass, UV–Vis, thermogravimetry analysis, and conductivity measurement data. Based on electronic spectral measurements, all three of the metal complexes were found to have octahedral stereochemistry. The way metal complexes interact with ct‐DNA was studied using various methods including absorption spectroscopy, fluorescence spectroscopy, and viscosity measurements. UV–Vis absorption technique has been used to explore the binding characteristics of M (II) complexes with ct‐DNA. The complexes bind to DNA via groove mode of binding, according to the spectral data. The salt‐dependent binding of ternary metal complexes to ct‐DNA has been studied by UV–Vis spectrophotometric titration experiment. Furthermore, gel electrophoresis is used to examine how the metal complexes interacted with the pBR322 DNA. The outcomes showed that these compounds can function as efficient DNA cleaving agents. Studies on the complexes' in vitro antibacterial activity demonstrated their importance and good antimicrobial activity at three distinct concentrations (50, 75, and 100 g/mL). [ABSTRACT FROM AUTHOR]

Using the aldehyde amine condensation procedure and the triphenylamine group as the skeleton structure, the new triphenylamine-aromatic aldehyde-succinylhydrazone probe molecule DHBYMH was created. A newly created acylhydrazone probe was structurally characterized by mass spectrometry (MS), NMR, and infrared spectroscopy (FTIR). Fluorescence and UV spectroscopy were used to examine DHBYMH's sensing capabilities for metal ions. Notably, DHBYMH achieved a detection limit of 1.62 × 10−7 M by demonstrating exceptional selectivity and sensitivity towards Cu2+ ions in an optimum sample solvent system (DMSO/H2O, (v/v = 7/3); pH = 7.0; cysteine (Cys) concentration: 1 × 10−4 M). NMR titration, high-resolution mass spectrometry analysis, and DFT computation were used to clarify the response mechanism. Ultimately, predicated on DHBYMH's reversible identification of Cu2+ ions in the presence of EDTA, a molecular logic gate was successfully designed. [ABSTRACT FROM AUTHOR]

A new Cu(II) complex, [CuL1L2(CH3COO)2(H2O)]·H2O, was synthesized by the reaction of Cu(CH3COO)2·H2O, 6-phenylpyridine-2-carboxylic acid (HL1), and 4-[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]pyridine (L2) in ethanol-water (v:v = 1:1) solution. The Cu(II) complex was characterized using elemental analysis, IR, UV-vis, TG–DTA, and single-crystal X-ray analysis. The fluorescence properties of the copper complex were also evaluated. The structural analysis results show that the Cu(II) complex crystallizes in the triclinic system with space group P-1. The Cu(II) ion in the complex is five-coordinated with one O atom (O2) and one N atom (N1) from one 6-phenylpyridine-2-carboxylate ligand (L1), one N atom (N2) from 4-[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]pyridine ligand (L2), one O atom (O4) from acetate, and one O atom (O5) from a coordinated water molecule, and it adopts a distorted trigonal bipyramidal geometry. Cu(II) complex molecules form a two-dimensional layer structure through intramolecular and intermolecular O-H...O hydrogen bonding. The two-dimensional layer structures further form a three-dimensional network structure by π-π stacking interactions of aromatic rings. The analysis of the Hirschfeld surface of the Cu(II) complex shows that the H...H contacts made the most significant contribution (46.6%) to the Hirschfeld surface, followed by O...H/H...O, N...H/H...N and C...H/H...C contacts with contributions of 14.2%, 13.8%, and 10.2%, respectively. In addition, the photocatalytic CO2 reduction using Cu(II) complex as a catalyst is investigated under UV-vis light irradiation. The findings reveal that the main product is CO, with a yield of 10.34 μmol/g and a selectivity of 89.4% after three hours. [ABSTRACT FROM AUTHOR]

Patterns of the preconcentration of Cu(II) and Zn(II) ions from aqueous solutions with N-nonanoyl-N'-mesylhydrazine by ion flotation are studied depending on the initial concentration of the coligends, pH of the solution, conditioning time, and temperature. Based on the data of IR spectroscopy and elemental analysis, an assumption is made about the composition of the floated compounds. It is shown that the extraction of Zn(II) significantly depends on the initial concentration of the metal and the time of solution conditioning. A decrease in the recovery of the studied ions with increasing solution temperature is established; for Cu(II) this effect is more pronounced. The kinetics of the process is described using a classical first-order model; the obtained values of flotation constants for Zn(II) ions are fivefold higher than those for Cu(II). The conditions for the selective separation of Cu(II) ions under collective flotation conditions are determined. [ABSTRACT FROM AUTHOR]

Schiff bases represent a class of biologically active and structurally diverse organic compounds that may be involved in copper(II) coordination as N,O-donor ligands. A redox-active biometal, copper is known to play a significant role in cellular metabolism and accounts for a wide range of biological activities exhibited by its compounds, namely antibacterial, antiproliferative, antifungal, antiinflammatory, etc. 4,6-Di-tert-butyl-2,3-dihydroxybenzaldehyde-derived Schiff bases and their Cu(II) complexes have been synthesized and characterized by means of FT-IR, UV-Vis, NMR and ESR spectroscopy, mass-spectrometry, elemental, XRD and thermogravimetric analysis, electrochemical measurements, quantum chemical calculations and molecular docking studies. The compounds were tested in vitro for antibacterial activity on Gram-positive and Gram-negative bacteria, bovine serum albumin and haemoglobin binding, as well as for hemolytic activity and for antioxidant activity in DPPH and ABTS assays. The synthesized ligands and their copper(II) complexes have been found to possess low cell toxicity and exhibit antioxidant activity higher than that of Trolox. Furthermore, several copper(II) complexes have demonstrated antibacterial activity comparable to those of tetracycline and streptomycin. The results obtained have been corroborated by molecular docking studies and interpreted in terms of the effects of copper(II) coordination by the organic ligand on radical-scavenging and bactericidal properties, protein affinity and toxicity of the latter. [ABSTRACT FROM AUTHOR]

Two newly designed ligands, [4-chloro-2-((((2-pyridyl)ethyl)imino)methyl)phenol] (HL1) and [4-bromo-2-((((2-pyridyl)ethyl)imino)methyl)phenol] (HL2), have been chosen to synthesize two Cu(II) dimeric Schiff base complexes, [CuL1Cl]2 (1) and [CuL2Cl]2 (2), with the aim of studying their catalytic activity towards oxidation of alcohols by using H2O2 as a terminal oxidant and reduction of nitroarenes by using NaBH4 as a reducing agent. The complexes have been characterized using physicochemical techniques and single crystal X-ray diffraction. DFT calculations of both the complexes have also been performed. Complex [CuL1Cl]2 (1) exhibited a higher catalytic efficiency in each reaction and therefore it was selected for building a magnetically separable catalyst by attaching it to surface modified magnetic nanoparticles. Then, our goal was to modify further complex 1 with iron oxide and isonicotinic acid (ISNA), for easy magnetic separation. The new Fe3O4@ISNA@CuL1 catalyst underwent comprehensive characterization, including FT-IR, SEM, TEM, and PXRD analyses, confirming successful copper complex immobilization on the magnetic nanoparticles. These catalysts maintained stability in aqueous and organic media, enabling alcohol oxidation with H2O2 in acetonitrile and nitroarene reduction with sodium borohydride in an aqueous environment. The surface modification with magnetic nanoparticles facilitated easy separation using an external magnet. The novelty of this work lies in its straightforward preparation, minimal time consumption, reduced use of hazardous chemicals, and cost-effectiveness. The catalysts showed recyclability up to five times without significant loss of activity. Furthermore, our synthesized catalysts demonstrated non-toxicity and environmental friendliness. [ABSTRACT FROM AUTHOR]

Since the discovery of cisplatin in the 1960s, the search for metallo-drugs that are more efficient than platinum complexes with negligible side effects has attracted much interest. Among the other metals that have been examined for potential applications as anticancer agents is copper. The interest in copper was recently boosted by the discovery of cuproptosis, a recently evidenced form of cell death mediated by copper. However, copper is also known to induce the proliferation of cancer cells. In view of these contradictory results, there is a need to find the most suitable copper chelators, among which Schiff-based derivatives offer a wide range of possibilities. Gathering several metal complexes in a single, larger entity may provide enhanced properties. Among the nanometric objects suitable for such purpose are dendrimers, precisely engineered hyperbranched macromolecules, which are outstanding candidates for improving therapy and diagnosis. In this review article, we present an overview of the use of a particular Schiff base, namely pyridine–imine, linked to the surface of dendrimers, suitable for complexing copper, and the use of such dendrimer complexes in biology, in particular against cancers. [ABSTRACT FROM AUTHOR]

A mesogenic glycine based Schiff base compound of the type, (E)‐methyl 2‐((2‐hydroxy‐4‐(tetradecyloxy)benzylidene)amino)acetate (HL) has been successfully synthesized and characterized using analytical and spectroscopic techniques. The Schiff base compound was evaluated for chemosensor activity towards different metal ions using fluorescence spectroscopy. The experiment reveals highly efficient and selective "turn‐on" and "turn‐off" responses of the fluorescence intensity towards zinc(II) and copper(II), respectively, in presence of other metal ions. The binding constant and the stoichiometry ratio were determined using Benesi‐Hildebrand equation giving 1 : 1 stoichiometry. The limits of detection for both the metal ions were estimated from the fluorescence titration experiments. The reversibility nature of the Schiff base probe was also studied using EDTA as chelating ligand. The compound, HL exhibits two INHIBIT logic gates with chemical inputs (i) Zn2+ (IN1) and Cu2+ (IN2) and (ii) Zn2+ (IN1) and EDTA (IN2). An IMPLICATION logic gate was also obtained when Cu2+ (IN1) and EDTA (IN2) serve as chemical inputs. The compound was found to exhibit potent antibacterial activity and efficient binding interaction with BSA. Molecular docking studies were carried out in order to ascertain the degree of interaction and the nature of binding of the compound with the proteins. [ABSTRACT FROM AUTHOR]

Metal complexes derived from Schiff bases are known to have a wide range of applications, spanning the areas of material and medicinal sciences. Herein, a Schiff base ligand, (Z)‐2‐(((4‐chlorophenyl)imino)methyl)naphthalen‐1‐ol HL, was synthesized via a condensation reaction between 2‐hydroxy‐1‐naphthaldehyde and 4‐chloroaniline using methanol as a solvent in the presence of a catalytic amount of formic acid. The obtained ligand was further reacted with Mn(II), Ni(II), and Cu(II) using their acetate salts in a 1 : 2 stoichiometric ratio of metal to ligand to afford complexes C1–C3, respectively. Physicochemical and analytical techniques consisting of FTIR, UV‐Vis, elemental (CHN and metal content), TGA, HRMS, 1H, and 13 C NMR spectroscopy were deployed to establish the formation of the compounds. Results show that the ligand coordinated with the metal ions through the oxygen and nitrogen atoms of the phenolate and azomethine moieties, respectively, forming ON‐type complexes. Furthermore, the free ligand and its complexes were evaluated for their antioxidant activity compared to the standard (ascorbic acid) using an in vitro DPPH radical scavenging assay. From this investigation, C1 demonstrated higher radical scavenging activity than the free ligand, the complexes, and the standard (ascorbic acid). But the ligand has better scavenging activity than C2 and C3 at higher concentrations. DFT was also used to examine the electronic properties of the compounds, and the data obtained corroborated well with the experimental study. [ABSTRACT FROM AUTHOR]

In the present study the behavior of Cu(II) and Zn(II) complexes with ethylenediamine and 2,2′:6′,2′′ terpyridine in an aqueous environment was studied by classical MD simulations. Special attention was paid to the effect of Cu2+ for Zn2+ substitution on complex water surroundings and mobility. The replacement of a metal ion affects the structure of the complex water environment only in the vicinity of its location. However, it changes such a characteristic as the lifetime of a water molecule in the first coordination shell of a metal which can significantly affect the mobility of the complex. Moreover, the degree of influence on translational and rotational mobility can be different. [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]

Antibiotic resistance is currently a global health emergency. Metallodrugs, especially metal coordination complexes, comprise a broad variety of candidates to combat antibacterial infections. In this work, we designed a new family of Schiff base zinc(II) complexes with iminopyridine as an organic ligand and different inorganic ligands: chloride, nitrate, and acetate. The antibacterial effect of the Zn(II) complexes was studied against planktonic bacterial cells of Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) strains. The results showed a moderate biocide activity in both types of planktonic bacteria, which arises from the metal complexation to the Schiff base ligand. Importantly, we confirmed the crucial effect of the metal, with Zn(II) improving the activity of Cu(II) counterparts previously reported. On the other hand, the impact of the inorganic ligands was not significant for the antibacterial effect but was relevant for the complex solubility. Finally, as proof of concept of topical antibacterial formulation, we formulated an emulsion containing the most lipophilic Zn(II) complex and confirmed a sustained release for 24 h in a vertical cell diffusion assay. The promising activity of iminopyridine Zn(II) complexes is potentially worth exploring in more detailed studies. [ABSTRACT FROM AUTHOR]

[Cu(5‐ClSal‐Trp)(bpy)]·CH3OH (1) and [Cu(3,5‐ClSal‐Trp)(bpy)]·H2O (2) (5‐ClSal‐Trp: Schiff base derived from 5‐chlorosalicylaldehyde and tryptophan, 3,5‐ClSal‐Trp: Schiff base derived from 3,5‐dichlorosalicylaldehyde and tryptophan, bpy: 2,2′‐bipyridine) have been synthesized and analyzed by CHN analysis, FTIR, electronic absorption spectroscopy, ESI‐MS and XRD techniques. Interaction of the complexes with biomolecules {calf thymus DNA (CT‐DNA) and bovine serum albumin (BSA)} has been researched by fluorescence and electronic absorption spectroscopy. The results show that the complexes can bind via a moderate intercalation binding mode. According to the results obtained with both methods, the logKb and logKSV values of the complexes were found to be very close to each other. BSA quenching mechanism was found to be static. The results showed that the interaction between the complexes and BSA is driven by the hydrogen bond and van der Waals interaction. Additionally, the r values of the complexes (the complex 1 = 0.59 nm and the complex 2 = 0.53 nm) calculated from FRET theory suggested that the distance between the complexes (acceptor) and BSA (donor) is quite close. The complexes exhibited free radical scavenging activity compared to the standard antioxidant β‐carotene and catechin. Antiproliferative efficiency of the complexes on both breast cancer cells (MCF‐7 and MDA‐MB‐231) were also researched using the Sulforhodamine B (SRB) viability assay. It was found that the complex 1 (IC50 = 10.99 μM) exhibited higher cytotoxicity than cisplatin (IC50 = 15.6 μM) against MDA‐MB‐231 cell line. Additionally, intracellular reactive oxygen species (ROS) formation was determined by dihydroethidium (DHE) fluorescent staining. N‐acetylcysteine (NAC) was used as an efficient reactive oxygen species (ROS) scavenger. It was observed that newly synthesized Cu (II) complexes exhibited anti‐growth potential in human breast cancer cells. Additionally, it was determined that the complexes induced reactive oxygen species (ROS) formation in cells in a dose‐dependent manner. [ABSTRACT FROM AUTHOR]

Gelatin, resulting from collagen, a naturally occurring protein found in ligaments and tissues, is formed through the boiling of connective tissues, bones and animal skins, commonly sourced from cows. Its exceptional properties, including the ability to form strong, transparent gels and flexible films, easy digestibility, solubility in hot water and positive binding action, make gelatin a highly valuable resource in various industries such as food processing, pharmaceuticals, photography and paper production. It is regarded as non-toxic, biocompatible, biodegradable and generally safe for use. Gelatin serves as a key ingredient in the manufacturing of a wide range of products, with a notable example being hard gelatin capsules, which come in varying levels of solubility in water. In this study, a Schiff base was synthesized by modifying gelatin with salicylaldehyde in ethanol at room temperature, a mixture of gelatin-Schiff base added to appropriate copper chloride sonicated in ethanol, the mixture was poured onto glass plates and allowed to dry. Modified gelatin film was produced and characterized using FTIR spectroscopy, while its surface properties were examined through Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Furthermore, the modified gelatin film's potential biological activity was assessed against bacterial strains. The antibacterial screening tests revealed that the modified gelatin exhibited promising antibacterial activity against microorganisms, indicating an improvement in its antibacterial efficacy. These findings highlight the enhanced antibacterial potential of the modified gelatin film, further contributing to its versatility and potential applications in various fields. Different molecular weight distributions within the gelatin can lead to variations in film formation and subsequent surface features. Additionally, the composition of the gelatin film, including the presence of any crosslinking agents or modified functional groups, can further influence the resulting surface morphology. This study focuses on the preparation of modified gelatin films using suitable aldehyde compounds and explores their potential for pharmaceutical applications. Various techniques assessment of biological activity will be employed to investigate the properties and performance of the modified gelatin films. [ABSTRACT FROM AUTHOR]

Here we describe the synthesis and characterization of three Schiff bases based on 4-aminoantipyrine, ligand A, ligand B, and ligand C. Ligand A was synthesized by reacting 4-aminoantipyrine with hydrazine, ligand B by reacting 4-aminoantipyrine with ethylenediamine, and ligand C by reacting 4-aminoantipyrine with benzaldehyde and hydrazine. The synthesis of the desired Schiff base derivatives was successfully achieved, as confirmed by elemental analysis, Fourier-transform infrared (FT-IR) spectroscopy, and nuclear magnetic resonance (1H and 13C NMR) spectroscopy. The obtained experimental results exhibited excellent agreement with previously published data. To evaluate the reactivity of the synthesized Schiff bases in forming stable metal complexes, their reaction with copper(II) ions was examined. The results indicated that ligand A and ligand B effectively utilized the four nitrogen atoms (NNNN) from the 4-aminoantipyrine-N and azomethine-N groups to coordinate with copper(II) ions, while ligand C coordinated with the copper(II) ions using its four azomethine nitrogen atoms. Furthermore, the manufactured copper(II) complexes were subjected to thermal treatment in the air at 600 °C for 3 h, resulting in the successful generation of copper(II) oxide. Scanning electron microscopy-energy-dispersive X-ray analysis data demonstrated that the produced copper(II) oxide exhibited high purity and possessed a uniform and well-structured morphology. [ABSTRACT FROM AUTHOR]

The primary objective of the current framework was to synthesize novel mononuclear 1:1:1 complexes involving FeLG, CoLG, NiLG, CuLG, and ZnLG, where the ligand (L) is identified as 4-[(4-oxo-4,5-dihydro-1,3-thiazol-2-yl)hydrazono]methylphenyl-4-methylbenzenesulfonate, and glycine (G) serves as the coligand. Comprehensive characterization of the investigated complexes was achieved through various analytical techniques, including FTIR, UV-Vis spectroscopy, elemental analysis, mass spectra, magnetic susceptibility measurements, molar conductivity assessments, and thermogravimetric analysis (TGA). The determination of stoichiometry was performed employing the molar ratio technique, revealing the octahedral geometry inherent in the isolated metal complexes. Employing a density functional theory (DFT) approach, the molecular structures of the designated compounds were theoretically elevated, and quantum chemical descriptors were derived to provide a deeper insight into their electronic properties. Furthermore, the inhibitory potential of these compounds against fungal strains and pathogenic bacteria prevalent in the Arab environment was evaluated using the disc diffusion method, emphasizing their role in combating diseases affecting humans, animals, and plants. Notably, the metal complexes exhibited superior antibacterial activity, as evidenced by a higher activity index. Molecular docking investigations were conducted to ascertain the inhibitory effects of the compounds on the 1FJ4 protein, with ZnLG emerging as the compound with the highest binding affinity. These results suggest the promising candidacy of these compounds as antimicrobial agents, particularly in the context of combating bacterial and fungal infections. [ABSTRACT FROM AUTHOR]

New 2-[(4-[(4-methylphenyl)sulfonothioyl)methylene]aminobenzoic acid ligand-Co(II), Ni(II), and Cu(II) complexes are synthesized and characterized in this article. Elemental analysis, mass spectroscopy, conductivity tests, magnetic susceptibility, Fourier transform infrared spectroscopy, thermogravimetric analysis, electronic absorption spectroscopy, and density functional theory calculations were used to determine the coordination mode, and geometry of the synthesized compounds. The Schiff-base ligand was shown to be mononegatively charged and coordinate to metal ions in a bi-dentate mode through azomethine nitrogen (-CH=N-) and carboxylic Oxygen (-COOH). Density functional theory (DFT) calculations were performed in addition to the experimental data to assess the most probable structures of the complexes. In addition, the biological activities of these compounds were evaluated by in vitro antibacterial and antifungal assays. These novel Co(II), Ni(II), and Cu(II) compounds were shown to be active against a wide variety of microorganisms, including Gram-positive and Gram-negative bacteria, as well as fungi. Following that, molecular docking was used to analyze the complexes' interactions with bacterial proteins, validating the therapeutic potential of the metal-containing compounds. [ABSTRACT FROM AUTHOR]

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 nonelectrolytic 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. [ABSTRACT FROM AUTHOR]

The ligand design factors that may influence the isolation of metallosupramolecular helicates or mesocates still deserve to be investigated. In this sense, dinuclear nickel(II), copper(II) and zinc(II) compounds were obtained by electrochemical synthesis using a family of five Schiff base ligands, H2Ln (n = 1–5), derived from bisphenylmethane and functionalized with bulky tert-butyl groups in the periphery and ethyl groups in the spacer. Six of the new complexes were characterized by X-ray crystallography, thus demonstrating that the helicate structure is predominant in the solid state. 1H NMR studies were performed for the zinc complexes to analyze if the helical architecture of the metal complexes is retained in solution. These studies reveal that the presence of a tert-butyl group in the ortho position with respect to the OH group is an essential factor identified for the existence of a helicate conformation in solution. [ABSTRACT FROM AUTHOR]

DNA minor groove binders (MGBs) are excellent carrier structures for chemotherapeutic applications with minimal side effects and dependable sequence specificity. The copper complex with the iminoenolate ligand exhibits excellent catalytic activity in azide–alkyne cycloaddition reactions. In this work, the structure–activity relationship (SAR) of copper(II) complexes with methoxy, unsubstituted and fluoro β-iminoenolate ligands (1a–c) was investigated towards DNA interactions and cytotoxicity. Molar conductance of complexes 1a–c was studied in methanol, and it provided evidence for the non-electrolytic nature of all three complexes in the solution. The DNA interactions with complexes 1a–c were investigated by absorption titration, competitive fluorescence titration with 4′,6-diamidino-2-phenylindole (DAPI), thermal denaturation and viscosity measurements. These four techniques reveal that complexes 1a–c bind to ds-DNA in the minor groove region. The calculated binding constant (Kb) values from the interaction studies reveal a higher binding propensity for the fluoro-substituted Cu(II) complex (1c) than the other complexes. Molecular docking studies reveal the DNA minor groove binding of complex 1c with a preference for the AT-rich region over the GC-rich region. Photocleavage studies revealed that 1a–c cleave PUC 19 DNA effectively in the presence of the reducing agent ascorbic acid. Mechanistic studies suggest that the hydroxyl radical (OH˙) plays a major role in DNA cleavage. The in vitro cytotoxicity study performed in human cancer cell lines viz., MDA-MB-231 (human breast cancer) and HEp-2 (human larynx epithelioma cancer) revealed that the fluoro-substituted complex (1c) was more cytotoxic than the other two complexes (1a–b) in vitro, with IC50 values of 24.2 μg mL−1 against the HeLa cell line and 32.7 μg mL−1 against MDA-MB-231. The findings imply that tuning the substituent in a ligand can improve the bioactivity of a metal complex. [ABSTRACT FROM AUTHOR]

There is a strong interest in monitoring copper in environmental waters, but its direct analysis suffers from strong matrix interferences. This is why, a sample pretreatment based on solid‐phase extraction (SPE) is often used but conventional sorbents usually lack specificity. It is overcome with ion‐imprinted polymers (IIPs). This work evaluates for the first time the use of the dummy approach for the synthesis of Cu(II)‐targeting IIPs. Two analog ions Ni(II) and Zn(II) were tested as templates and the resulting IIPs were packed in SPE cartridges. The SPE procedure was designed by optimizing a washing step following the sample percolation, to eliminate the interfering ions retained on the IIP by non‐specific interactions. To optimize the washing step, solutions at different pH or containing tris(hydroxymethyl)aminomethane as a complexing agent at different concentrations were tested and combined. Zn‐IIP appeared more promising than Ni‐IIP, showing excellent specificity and a high selectivity. Its retention capacity was determined to be 100 µg/g, and different isotherm models were evaluated to fit with the adsorption data. Finally, applications to mineral and sea waters were successfully completed and led to high and repeatable extraction recoveries for Cu(II) (88 ± 1% and 83 ± 3%, respectively). [ABSTRACT FROM AUTHOR]

The current work reports the synthesis of mixed ligand‐metal complexes of (2‐(2‐oxoacenaphthylen‐1 ylidene)hydrazinecarbothioamide) (L1) and carbamothioyl‐2‐chloronicotinohydrazonic acid (L2) and imidazole (im), triphenylphosphine (PPh3) and pyridine (py) ligands with Cu (II), Zn (II), Fe (II) and Co (II) salts.The chacterization was done through FT‐IR, NMR, UV‐visible, and elemental analysis. The X‐ray diffraction (XRD) patterns of [Cu(L1)(im)2(SO4)] demonstrated the crystalline morphology. In the FT‐IR spectra of the ligands, the characteristic frequencies corresponding to ν(C=N) (imine) and ν(C=S) (thiocarbonyl) were observed around 1650 and 1130 cm−1 respectively, which shifted upon complexation. In the 1H NMR spectra, the peak due to the NH proton was observed downfield, whereas that of ‐NH2 was observed comparatively upfield owing to its secondary amine nature. The molecular docking was performed against transforming growth beta (tgf‐β), protease of SARS‐CoV‐2 (Mpro) and aspartate kinase (Asp) kinase.The molecular simulation with the docked complex of [Zn(L2)(py)2(SO4)] and [Zn(L1)(PPh3)2(SO4)] with Asp kinase showed significant stability during the simulation time of 100 ns. The relative free energies of the simulated complexes were calculated with the molecular mechanics Poison‐Boltmann surface area (MM‐PBSA). The complexes were tested against ten bacterial strains and showed enhanced antibacterial activity than the ligands. [Cu(L1)(im)2(SO4)], [Zn(L1)(im)2(SO4)], [Fe(L1)(im)2(SO4)] and [Co(L1)(im)2(Cl2)] were found to be active against E.coli. [ABSTRACT FROM AUTHOR]

Herein, the design and synthesis of three new copper(II) chloro-benzoato complexes (2C4NB = 2-chloro-4-nitrobenzoate; 2C5NB = 2-chloro-5-nitrobenzoate) with N-/O-donor, i.e. ethanolamine (ethmn) and N-hydroxyethyl-ethylenediamine (N-hyden), [Cu(ethmn)2(2C4NB)2] (1), [Cu(N-hyden)2](2C5NB)2 (2), and [Cu(N-hyden)2(2C4NB)2] (3), have been achieved for the first time under ambient conditions. All the three complexes (1–3) were structurally characterized, along with elemental and spectroscopic analyses (UV-visible, FT-IR) and other studies. Structure elucidation using single crystal X-ray diffraction clearly revealed the exact geometry and nature of bonding, i.e. covalent (1), ionic (2), and covalent (3), with distorted octahedral geometry in all cases. Deep insights into the X-ray structures of complexes 1–3 indicated that the disorientation of the nitro-group from its mean plane in 2C4NB of complexes 1 and 3 is lesser compared to that of 2C5NB of complex 2, resulting in different natures of coordination complexes. Packing analysis showed that various weak (non-covalent) interactions such as O–H⋯O, N–H⋯O, C–H⋯O, anion⋯π, and C–H⋯π play an important role in the lattice stabilization of complexes 1–3, in agreement with the Hirshfeld surface analysis revealing an interplay of non-covalent interactions in the lattice stabilization of these complexes, supporting the packing analyses. Theoretical calculations estimated the total interaction energies and band gap (i.e. HOMO–LUMO energy differences) of complexes 1–3. Antimicrobial activities of complexes 1–3 were evaluated, and the results showed that all the three complexes exhibited remarkable activities against both Gram-positive (B. cereus and S. aureus) and Gram-negative bacteria (E. coli, S. typhi, P. aeruginosa, and S. flexneri). The potential antibacterial efficacy of complexes 1 and 2 is comparable to that of chloramphenicol. In addition, molecular docking investigations of complexes 1–3 clearly showed that in silico and experimental anti-microbial studies were similar in terms of their performance. Complexes 1–3 showed docking scores of −7.6, −7.4, and −7.5 kcal mol−1 against SARS-CoV-2 (PDB ID: 7Z0P), which were better than the standard drugs chloroquine and molnupiravir against SARS-CoV-2. [ABSTRACT FROM AUTHOR]

A novel coumarin-derived Schiff base fluorescent probe was reported to detect Cu2+ ions in human cells. It was synthesized by the reaction between 7-(diethylamino)coumarin-3-carbohydrazide and pyridoxal 5′-phosphate. The probe has good stability and it exhibited obviously decreasing fluorescent response at λ 490 nm upon addition of Cu(II) ions. The fluorescent probe showed high selectivity for Cu(II) ions compared to other metal ions. The probe has been successfully applied to detect Cu(II) ions in human cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • The environmentally friendly magnetic MS-Sp-P [5] -bodipy microcapsule sensor has successfully synthesized for the selective and sensitive detection of Cu(II) and Hg(II) ions in aqueous media. • The magnetic MS-Sp-P [5] -bodipy microcapsule sensor surface was characterized by several techniques such as FT-IR, SEM, XRD. • The photophysical measurements were fluorometrically performed for the detection of Hg(II) and Cu(II) ions in the fluorescence spectroscopy that the limit of detection is 0.06 µM and 2.27 µM. respectively. In this study, a new bodipy/pillar[5]arene functionalized magnetic MS-Sp-P[5]-bodipy microcapsule sensor was prepared based on the use of environmentally friendly for the selective and sensitive detection of Cu(II) and Hg(II) ions in aqueous media. SEM results used in the characterization process of the materials synthesized at each stage confirmed the structural and morphological changes in the pore structure, while other characterization results (FT-IR and XRD) elucidated the role of pillar[5]arene compound and bodipy dye in the synthesis of magnetic microcapsule sensors. The colloidal solution of MS-Sp-P[5]-bodipy (water/ethanol)) showed two fluorescence bands centered at 402 and 540 nm. The detection limits of MS-Sp-P[5]-bodipy for Hg(II) and Cu(II) were calculated to be 0.06 µM and 2.27 µM, respectively (at 540 nm). The linear range of the magnetic sensor for Hg(II) and Cu(II) was found to be in the range of 1–150 µM and 10–150 µM, respectively. The experimental results (response time, pH, temperature, sensitivity and selectivity) demonstrated the applicability and potential of the prepared magnetic microcapsule sensor for the detection of Cu(II) and Hg(II) in water and tap water samples containing heavy metal ions. [ABSTRACT FROM AUTHOR]

The Cu(II) was found using a quick and uncomplicated procedure that involved reacting it with a freshly synthesized ligand to create an orange complex that had an absorbance peak of 481.5 nm in an acidic solution. The best conditions for the formation of the complex were studied from the concentration of the ligand, medium, the effect of the addition sequence, the effect of temperature, and the time of complex formation. The results obtained are scatter plot extending from 0.1–9 ppm and a linear range from 0.1–7 ppm. Relative standard deviation (RSD%) for n = 8 is less than 0.5, recovery % (R%) within acceptable values, correlation coefficient (r) equal 0.9986, coefficient of determination (r2) equal to 0.9973, and percentage capital R-squared explained variation as a percentage/total variation (R2%) equal to 99.73. The method has been successfully applied for the estimation of Cu(II) ions without the influence of other interfering ions, and it can be applied to estimate Cu(II) in any sample. [ABSTRACT FROM AUTHOR]

A series of 12 salicylidene‐based homoleptic nickel(II), copper(II) and zinc(II) complexes with the general formula [M(L1–4)2] (1–12) containing the tridentate ligands 2‐(((2‐(([1,1′‐biphenyl]‐3‐ylmethylene)amino)phenyl)imino)methyl)phenol (HL1), 2‐(((2‐(([1,1′‐biphenyl]‐3‐ylmethylene)amino)phenyl)imino)methyl)‐4‐methoxyphenol (HL2), 2‐(((2‐(([1,1′‐biphenyl]‐3‐ylmethylene)amino)phenyl)imino)methyl)‐4‐ethoxyphenol (HL3) and 2‐(((2‐(([1,1′‐biphenyl]‐3‐ylmethylene)amino)phenyl)imino)methyl)‐4‐nitrophenol (HL4) have been synthesized and characterized by spectroscopic analysis. The tridentate nature of the ligands form an octahedral geometry around the central metal ion through the phenolic oxygen via deprotonation and two azomethine nitrogen atoms. Further, the charge transfer transitions taking place in the complexes have been explained using HOMO‐LUMO analysis. The in vitro cytotoxicity activity screened by WST assay against human metastatic (MDA‐MB‐231), hepatoma (HepG2) and colorectal adenocarcinoma (CaCo2) cancerous, and normal mouse fibroblast (NIH3T3) cell lines showed higher activity for the complexes 2, 6 and 10 with respect to the standard drug 5‐fluorouracil. The AO/EB, PI, Rh123 and DCFH‐DA staining results indicated that the complexes induced anticancer activity through apoptosis. Furthermore, the complexes interact with FGFR and P13Kγ kinase receptors through the hydrophobic, hydrogen bonding, π–π, σ–π, van der Waals and electrostatic interaction. [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]

Cu thin films and Cu2O microstructures were partially converted to the Metal‐Organic Frameworks (MOFs) Cu3(BTC)2 or Cu(TCPP) using an electrochemical process with a higher control and at milder conditions compared to the traditional solvothermal MOF synthesis. Initially, either a Cu thin film was sputtered, or different kinds of Cu or Cu2O microstructures were electrochemically deposited onto a conductive ITO glass substrate. Then, these Cu thin films or Cu‐based microstructures were subsequently coated with a thin layer of either Cu3(BTC)2 or Cu(TCPP) by controlled anodic dissolution of the Cu‐based substrate at room temperature and in the presence of the desired organic linker molecules: 1,3,5‐benzenetricarboxylic acid (BTC) or photoactive 4,4′,4′′,4′′′‐(Porphine‐5,10,15,20‐tetrayl) tetrakis(benzoic acid) (TCPP) in the electrolyte. An increase in size of the Cu micro cubes with exposed planes [100] of 38,7 % for the Cu2O@Cu3(BTC)2 and a 68,9 % increase for the Cu2O@Cu(TCPP) was roughly estimated. Finally, XRD, Raman spectroscopy and UV–vis absorption spectroscopy were used to characterize the initial Cu films or Cu‐based microstructures, and the obtained core‐shell Cu2O@Cu(BTC) and Cu2O@Cu(TCPP) microstructures. [ABSTRACT FROM AUTHOR]

Template condensation of S-methylisothiosemicarbazones of acetyl- or benzoylacetone with 8‑quinolinecarboxaldehyde in the presence of nickel(II) and copper(II) ions gave four new mononuclear coordination compounds [NiL1]I (I), [CuL1I] (II), [NiL2]I (III), and [CuL2I] (IV). The chemical composition of the products was confirmed by elemental analysis, IR spectroscopy, and mass spectrometry, and the crystal structure of compounds I and II was determined by X-ray diffraction analysis (CCDC nos. 2266386, 2266387). X-ray diffraction study revealed a square planar coordination environment of the central ion of the cationic Ni(II) complex and square pyramidal geometry for the molecular Cu(II) complex. [ABSTRACT FROM AUTHOR]

In search of effective copper-based anticancer drug candidates, a new series of novel chloro-bridged binuclear copper(II) complexes of the type [Cu2(L)2(μ-Cl)2] was synthesized through the metallation of benzoyl pyridine hydrazone ligands (HL1–HL5) with [Cu(DMSO)2Cl2]. Single-crystal X-ray diffraction data revealed that two copper metal centres were bridged through a pair of chloride ions making a square pyramidal geometry around each bivalent copper ion, which was further supported by spectral data. Properties of complexes 1–5, such as stability at biological pH and cellular uptake, were also assessed. The potential of these complexes to bind with DNA/BSA was promising with significant binding constant values in the range 104–106. A catechol oxidase enzyme mimicking activity study revealed that all the complexes can catalyse the conversion of 3,5-di-tert-butylcatechol (3,5-DTBC) into 3,5-tert-butylquinoline (3,5-DTBQ) under aerobic conditions. In addition, IC50 values determined from the in vitro cytotoxicity of complexes 1–5 against colon cancer cells (HCT 116) and normal skin cells (L929) indicated that they possess appreciable cytotoxicity towards the former cells with an average concentration of 35 μM leaving the latter unaffected up to 200 μM (average). Acridine orange/ethidium bromide (AO/EB) dual-staining, reactive oxygen species (ROS) staining and mitochondrial membrane potential (MMP) assays were performed to assess the therapeutic efficacy of selective complexes against colon cancer cells, and an effective cell arresting ability of the complexes was observed. The results indicated that the synthesized complexes could be further exploited as novel therapeutic agents against cancer. [ABSTRACT FROM AUTHOR]

We report the synthesis, characterization and anticancer activity of a new Schiff base (H2L) derived from the condensation of pyridoxamine with pyridoxal and its novel copper(II) and oxidovanadium(IV) complexes: [Cu(HL)Cl] (1), [Cu(LH2)(phen)]Cl2 (2), [Cu(LH2)(amphen)]Cl2 (3), [VIVO(HL)Cl] (4), and [VIVO(LH2)(phen)]Cl2 (5), where phen is 1,10-phenanthroline and amphen is its 5-amino derivative. All compounds were characterized by analytical and spectroscopic techniques, namely FTIR, UV-vis and EPR spectroscopy. Their stability in aqueous media was evaluated, revealing that the presence of the phen co-ligand significantly increases the stability. The ternary Cu(II) complexes (2 and 3) impaired cell viability of osteosarcoma cells (MG-63) (IC50 values of 3.6 ± 0.6 and 7 ± 1.9 μM for 2 and 3), while 1 and the VIVO complexes did not show relevant anticancer activity. Complexes 2 and 3 are also more active than cisplatin (CDDP). Synergistic studies between 2 and sorafenib showed significant synergism on MG-63 cells for the following combinations: 2 (2.0 μM) + sorafenib (10.0 μM) and 2 (2.5 μM) + sorafenib (12.5 μM), whilst the combination of 2 and CDDP did not show synergy. Complex 2 interacts with DNA, inducing significant genotoxic effects on MG-63 cells from 1.0 to 2.5 μM and it increases the ROS levels 880% over basal. Moreover, 2 induces apoptosis at 1.0 and 2.0 μM, while its combination with sorafenib induces apoptosis and necrosis. Finally, compound 2 reduces the cell viability of MG-63 spheroids showing an IC50 value 7-fold lower than that of CDDP (8.5 ± 0.4 μM vs. 65 ± 6 μM). The combination of 2 and sorafenib also showed synergism on spheroids, suggesting that the combination of these drugs improves the anticancer effect against bone cancer cells. [ABSTRACT FROM AUTHOR]

A set of three copper(II) complexes C28H24CuN4O2[CuL1], C24H22CuN4O [CuL2] and C26H22CuN4O [CuL3] incorporated with ligands 1‐benzyl‐1H‐indazol‐3‐ol, 2,2′‐bipyridyl and 1,10‐phenanthroline have been synthesized, characterized and subjected for biomedical applications. New copper(II) derivatives were characterized by FTIR, EPR and HRMS spectral tools. Cyclic voltammograms were recorded to ascertain redox potential and UV‐Vis and Fluorometer were employed to establish photophysical properties of all the new copper(II) complexes. Further, these derivatives of Cu(II) were subjected for DNA and BSA binding studies by using absorption‐emission spectral methods and viscosity measurements as well as by molecular docking. DFT studies of the above‐mentioned derivatives suggested square planar geometry along with other relevant molecular investigations. Eventually, these new Cu(II) complexes have been tested with DPPH and MTT assay to determine the cytotoxicity against MCF7 cell lines to observe remarkable potency with IC50 values 80.68 μg/ml, 49.40 μg/ml and 45.91 μg/ml, respectively. [ABSTRACT FROM AUTHOR]

In the present work, we report a neutral dinuclear copper(II) complex, [Cu2(L1)(OH)], derived from a new [N,O] donor Schiff base ligand L1 that was formed after the endogenous hydroxylation of an initial carbamate Schiff base H2L coordinated with copper ions in an electrochemical cell. The copper(II) complex has been fully characterized using different techniques, including X-ray diffraction. Direct current (DC) magnetic susceptibility measurements were also performed at variable temperatures, showing evidence of antiferromagnetic behavior. Its catalase-like activity was also tested, demonstrating that this activity is affected by temperature. [ABSTRACT FROM AUTHOR]