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In the present work, we report a neutral dinuclear copper(II) complex, [Cu 2 (L 1 )(OH)], derived from a new [N,O] donor Schiff base ligand L 1 that was formed after the endogenous hydroxylation of an initial carbamate Schiff base H 2 L 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.

A new mononuclear Cu(II) complex [Cu(L 2 )(H 2 O) 2 ], where L is the Schiff base 2-[2-(3-bromopropoxy)benzylideneamino] benzoic acid, was synthesized and covalently anchored onto an amino-functionalized SBA-15 mesoporous silica in order to obtain an efficient heterogeneous catalyst. The elemental, structural, textural and morphological characterization confirmed the coordination of the central Cu(II) ion with two ligands and two H 2 O molecules in the synthesized complex and its successful immobilization into the inner pore surface of the NH 2 -functionalized support without the loss of the mesoporous structure. The catalytic activity of the free or immobilized Cu(II) complex was tested in the oxidation of cyclohexene with H 2 O 2 under an air atmosphere and the dismutation reaction of the superoxide radical anions with very good results. In addition, catalyst reuse tests claim its suitability in alkene oxidation processes or as a biomimetic catalyst.

The study of the inherent factors that influence the isolation of one type of metallosupramolecular architecture over another is one of the main objectives in the field of Metallosupramolecular Chemistry. In this work, we report two new neutral copper(II) helicates, [Cu 2 (L 1 ) 2 ]·4CH 3 CN and [Cu 2 (L 2 ) 2 ]·CH 3 CN, obtained by means of an electrochemical methodology and derived from two Schiff-based strands functionalized with ortho and para-t-butyl groups on the aromatic surface. These small modifications let us explore the relationship between the ligand design and the structure of the extended metallosupramolecular architecture. The magnetic properties of the Cu(II) helicates were explored by Electron Paramagnetic Resonance (EPR) spectroscopy and Direct Current (DC) magnetic susceptibility measurements.

The three Schiff base ligands, derivatives of hesperetin, HHSB ( N -[2,3-dihydro-5,7-dihydroxy-2-(3-hydroxy-4-methoxyphenyl)chromen-4-ylidene]isonicotinohydrazide), HIN ( N -[2,3-dihydro-5,7-dihydroxy-2-(3-hydroxy-4-methoxyphenyl)chromen-4-ylidene]benzhydrazide) and HTSC ( N -[2,3-dihydro-5,7-dihydroxy-2-(3-hydroxy-4-methoxyphenyl)chromen-4-ylidene]thiosemicarbazide) and their copper complexes, CuHHSB, CuHIN, and CuHTSC were designed, synthesized and analyzed in terms of their spectral characterization and the genotoxic activity. Their structures were established using several methods: elemental analysis, FT-IR, UV-Vis, EPR, and ESI-MS. Spectral data showed that in the acetate complexes the tested Schiff bases act as neutral tridentate ligand coordinating to the copper ion through two oxygen (or oxygen and sulphur) donor atoms and a nitrogen donor atom. EPR measurements indicate that in solution the complexes keep their structures with the ligands remaining bound to copper(II) in a tridentate fashion with (O - , N, O ket ) or (O - , N, S) donor set. The genotoxic activity of the compounds was tested against model tumour (HeLa and Caco-2) and normal (LLC-PK1) cell lines. In HeLa cells the genotoxicity for all tested compounds was noticed, for HHSB and CuHHSB was the highest, for HTSC and CuHTSC-the lowest. Generally, Cu complexes displayed lower genotoxicity to HeLa cells than ligands. In the case of Caco-2 cell line HHSB and HTSC induced the strongest breaks to DNA. On the other side, CuHHSB and CuHTSC induced the highest DNA damage against LLC-PK1.

An aggregation-induced emission (AIE) active Schiff base L was obtained by reacting pyridoxal and 2-hydroxy-1-naphthaldehyde with p-phenylenediamine in two simple steps. The colorimetric, UV/VIS and fluorescence studies of L revealed that the yellow emissive L (λ em =540 nm, λ ex =450 nm) in pure DMSO turned to a red-emissive L, when the poor solvent fraction (HEPES buffer, 10 mM, pH 7.4) was increased above 50 % in DMSO. The SEM and DLS results indicated the formation of self-aggregates of L that restricted the intramolecular motion and promoted the excited state intramolecular proton transfer (ESIPT) process. The cations sensing ability of the AIEgen L was explored in HEPES buffer (5 % DMSO, 10 mM, pH 7.4), where Cu 2+ selectively quenched the fluorescence at 608 nm due to the chelation-enhanced fluorescence quenching (CHEQ) effect with an estimated sensitivity limit of 0.9 μM. Subsequently, the in situ formed AIEgen L-Cu 2+ complex was applied for the cascade detection of glutathione (GSH), cysteine (Cys) and homocysteine (Hcy). The decomplexation of Cu 2+ from the AIEgen L-Cu 2+ by GSH, Cys and Hcy restored the quenched fluorescence emission of AIEgen L at 608 nm. With this Cu 2+ displacement approach, the concentration of Cys, Hcy and GSH can be detected down to 2.8 μM, 3.12 μM and 2.0 μM, respectively. The practical utility of AIEgen L and AIEgen L-Cu 2+ was examined by monitoring the selective analytes in real environmental and biological samples, and also applied successfully for the cell imaging applications., (© 2022 Wiley-VHCA AG, Zurich, Switzerland.)

Herein, we report two acyclic Schiff base receptors CS-1 and CS-2 capable of being selective fluorescent turn on for Zn 2+ ions and colorimetric chemosensor for Zn 2+ , Cu 2+ , and Co 2+ ions by showing a colour change from colourless to yellow in 1:1 ratio of acetonitrile and HEPES buffer (1:1, v/v, pH 7.4) without the interference from other metal ions screened (Cd 2+ , Hg 2+ , Sn 2+ , Ni 2+ , Cr 3+ , Mn 2+ , Pb 2+ , Ba 2+ , Al 3+ , Ca 2+ , Mg 2+ , K + and Na + ). The fluorescence turn on enhancement towards Zn 2+ ions is ascribed to PET blocking, suppression of -C=N- isomerisation, and the ESIPT process. The selectivity, competitivity and reversibility of the synthesised probes (CS-1 and CS-2) made them promising chemosensors for the detection of Zn 2+ , Cu 2+ , and Co 2+ ions. The density functional theory (DFT) calculations have theoretically endorsed the colorimetric changes in the examined absorption spectra and binding mode of both CS-1/CS-2 with metals ions. In addition, 1 H NMR titrations were also consistent with the recognition mechanism of Zn 2+ ions with the CS-1/CS-2. Further, the Jobs plot analysis infers a 1:1 stoichiometric ratio for both evaluating receptors CS-1 and CS-2 with Zn 2+ , Cu 2+ and Co 2+ ions and was supported by DFT, NMR (only for Zn 2+ ions), UV-Visible, and fluorescence spectroscopic studies. Moreover, the detection limits of CS-1 and CS-2 for Zn 2+ ions were determined to be 7.69 and 5.35 nM, respectively, which is less compared to the detection limit of Cu 2+ , Co 2+ ions as well as the limit approved by the United State Environmental Protection Agency (US EPA). The probes CS-1 and CS-2 found to show high fluorescence quantum yields at pH = 7 during the titration with Zn 2+ as compared with other pHs (5-6 and 8-11). Gratifyingly, fluorescence microscopy imaging in HeLa cells revealed that the pair of receptors can be employed as an excellent fluorescent probe for the detection of Zn 2+ ions in living cells, indicating that this facile chemosensor has a huge potential in cellular imaging., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Three bis-benzimidazolyl bidentate ligands with phenolyl ether linkers, 1,n-bis[2-(1H-1,3-benzimidazol-1-ylmethyl)phenoxy]alkane (L1: n = 1, L2: n = 3, L3: n = 4), and their six metal complexes were synthesized by the reactions of the respective ligands with metal salts. The six metal complexes included two cobalt(II) complexes ([Co(L1)(NO3)2] (1) and [Co(L3)(LA)]n (6) (LA = maleate)), two copper(II) complexes ([Cu(L1)(SO4)]2 (4) and [Cu(L3)(SO4)]2 (5)), one zinc(II) complex ([Zn(L1)(NO3)2] (2)) and one nickel(II) complex ([Ni(L2)(NO3)2] (3)). Complexes 1 and 2 had one 16-membered macrometallocycle, and complex 3 had one 18-membered macrometallocycle. In complexes 4 and 5, two SO42- joined two macrometallocycles together (16-membered macrometallocycle for 4 and 19-membered macrometallocycle for 5). In complexes 1-5, each macrometallocycle was constructed from one ligand and one metal ion. In complex 6, 19-membered macrometallocycles were connected together by maleate groups (LA) to form a 1D polymeric chain, where each 19-membered macrometallocycle was constructed from one L3 and one Co(II) ion. In crystal packings of complexes 1-6, H-bonds, π--π interactions and C--H•••π contacts participated in the formation of 2D supramolecular layers and 3D supramolecular architectures. The conformations of complexes 1-6 were also analyzed. Additionally, the recognition performance of complex 1 as a chemosensor for HSO4- was studied through fluorescence spectra, UV/vis spectra, 1H NMR titrations, HRMS spectra and IR spectra. The large binding constant (1.81 x 104 M-1) showed that there was a strong acting force between 1 and HSO4-, and the low detection limit (1.40 x 10-7 mol L-1) indicated that the detection of 1 for HSO4- was sensitive. The experimental results showed that complex 1 can effectively differentiate HSO4- from other anions. [ABSTRACT FROM AUTHOR]

Three bis-benzimidazolyl bidentate ligands with phenolyl ether linkers, 1,n-bis[2-(1H-1,3-benzimidazol-1-ylmethyl)phenoxy]alkane (L1: n = 1, L2: n = 3, L3: n = 4), and their six metal complexes were synthesized by the reactions of the respective ligands with metal salts. The six metal complexes included two cobalt(II) complexes ([Co(L1)(NO3)2] (1) and [Co(L3)(LA)]n (6) (LA = maleate)), two copper(II) complexes ([Cu(L1)(SO4)]2 (4) and [Cu(L3)(SO4)]2 (5)), one zinc(II) complex ([Zn(L1)(NO3)2] (2)) and one nickel(II) complex ([Ni(L2)(NO3)2] (3)). Complexes 1 and 2 had one 16-membered macrometallocycle, and complex 3 had one 18-membered macrometallocycle. In complexes 4 and 5, two SO42- joined two macrometallocycles together (16-membered macrometallocycle for 4 and 19-membered macrometallocycle for 5). In complexes 1-5, each macrometallocycle was constructed from one ligand and one metal ion. In complex 6, 19-membered macrometallocycles were connected together by maleate groups (LA) to form a 1D polymeric chain, where each 19-membered macrometallocycle was constructed from one L3 and one Co(II) ion. In crystal packings of complexes 1-6, H-bonds, π--π interactions and C--H•••π contacts participated in the formation of 2D supramolecular layers and 3D supramolecular architectures. The conformations of complexes 1-6 were also analyzed. Additionally, the recognition performance of complex 1 as a chemosensor for HSO4- was studied through fluorescence spectra, UV/vis spectra, 1H NMR titrations, HRMS spectra and IR spectra. The large binding constant (1.81 x 104 M-1) showed that there was a strong acting force between 1 and HSO4-, and the low detection limit (1.40 x 10-7 mol L-1) indicated that the detection of 1 for HSO4- was sensitive. The experimental results showed that complex 1 can effectively differentiate HSO4- from other anions. [ABSTRACT FROM AUTHOR]

The article focuses on recent advancements in chemistry, highlighting the development of new materials and chemical processes. Topics include the synthesis of insensitive energetic materials with enhanced detonation performance, the use of vanadium(V) complexes for syndiospecific ring-opening metathesis polymerization (ROMP) of cyclic olefins, and the exploration of metal-support interactions to enhance catalytic activity for hydrogen production.

Two mononuclear complexes, [Cu(L1)2] (complex 1) and [Cu(HL2)2](NO3)2 (complex 2) where HL1 is 1-((cyclohexylmethylimino)methyl)-naphthalen-2-ol and HL2 is 4-bromo-2-((2-morpholinoethylimino)methyl)phenol, have been synthesized under mild conditions and characterized by different standard analytical methods. Single crystal X-ray diffraction analysis shows that the copper atoms in both copper(II) complexes are in a square planar geometry. These complexes have been used as catalysts in the oxidation of benzyl alcohol and benzyl alcohol with various substituents in the presence of NaOCl as the terminal oxidant. The results show that complex 1 acts as a better catalyst than the other with the highest yield of 91% in the case of 4-methoxy benzyl alcohol oxidation. The copper complex transfers the oxygen of sodium hypochlorite to the alcohol to produce the aldehyde. The use of NaOCl as an oxidant in alcohol oxidation is rare although it is cheap and nonexplosive. [ABSTRACT FROM AUTHOR]

Several novel copper (II) complexes of reduced Schiff bases containing fluoride substituents were prepared and structurally characterized by single-crystal X-ray diffraction. The complexes exhibited diverse structures, with the central atom in distorted tetrahedral geometry. The biological effects of the products were evaluated, specifically their cytotoxicity, antimicrobial, and antiurease activities, as well as affinity for albumin (BSA) and DNA (ct-DNA). The complexes showed marked cytotoxic activities in the HepG2 hepatocellular carcinoma cell line, considerably higher than the standard cisplatin. The cytotoxicity depended significantly on the substitution pattern. The best activity was observed in the complex with a trifluoromethyl group in position 4 of the benzene ring—the dichloro[(±)-trans-N,N′-bis-(4-trifluoromethylbenzyl)-cyclohexane-1,2-diamine]copper (II) complex, whose activity (IC50 28.7 μM) was higher than that of the free ligand and markedly better than the activity of the standard cisplatin (IC50 336.8 μM). The same complex also showed the highest antimicrobial effect in vitro. The affinity of the complexes towards bovine serum albumin (BSA) and calf thymus DNA (ct-DNA) was established as well, indicating only marginal differences between the complexes. In addition, all complexes were shown to be excellent inhibitors of the enzyme urease, with the IC50 values in the lower micromolar region. [ABSTRACT FROM AUTHOR]

The present study focuses on the synthesis and structural characterization of a novel dinuclear CuII complex, [trichloridocopper(II)]-μ-chlorido-{bis[2-hydroxy-N′-(propan-2-ylidene)benzohydrazide]copper(II)} monohydrate, [Cu2Cl4(C10H12N2O2)2]·H2O or [Cu(H2L)2(μ-Cl)CuCl3]·H2O [H2L = 2-hydroxy-N′-(propan-2-ylidene)benzohydrazide]. The complex crystallizes in the monoclinic space group P21/n with one molecule of water, which forms interactions with the ligands. The first copper ion is penta-coordinated to two benzohydrazine-derived ligands via two nitrogen and two oxygen atoms, and one bridging chloride, which is also coordinated by the second copper ion alongside three terminal chlorines in a distorted tetrahedral geometry. The arrangement around the first copper ion exhibits a distorted geometry intermediate between trigonal bipyramidal and square pyramidal. In the crystal, chains are formed via intermolecular interactions along the a-axis direction, with subsequent layers constructed through hydrogen-bonding interactions parallel to the ac plane, and through slipped π–π stacking interactions parallel to the ab plane, resulting in a three-dimensional network. The intermolecular interactions in the crystal structure were quantified and analysed using Hirshfeld surface analysis. Residual electron density from disordered methanol molecules in the void space could not be reasonably modelled, thus a solvent mask was applied. [ABSTRACT FROM AUTHOR]

Salamo‐type ligand H2L was designed and synthesized and reacted with Cu (II) and Zn (II) acetate, respectively, to obtain two binuclear Cu (II) and Zn (II) complexes: [Cu2(L)2]·2CH3OH (1) and [Zn2(L)2] (2) having the same coordination number but distinct geometries. Complex 1 is a Cu (II) complex containing two crystalline ethanol molecules, where two Cu (II) atoms are surrounded by two utterly deprotonated (L)2− parts, forming slightly twisted tetragonal pyramidal configurations of pentacoordinate. In complex 2, two utterly deprotonated (L)2− parts surround two Zn (II) atoms, forming pentadentate twisted triangular bipyramidal configurations. The complexes were elucidated via IR analyses and ultraviolet spectroscopy. Using DFT theoretical calculation, MEPs, IRI, and Hirshfeld surface analysis to investigate further the molecular interactions and reaction sites. Ultimately, the fluorescence characteristics of H2L and its complexes 1 and 2 were discussed. [ABSTRACT FROM AUTHOR]

ABSTRACT N‐Methylbenzylamine and ethylenediamine were utilized as primary and auxiliary ligands, respectively, alongside metal salts to synthesize ternary metal complexes: [FeCl3(Nmba)(en)], [CoCl2(Nmba)(en)(H2O)] and [CuCl2(Nmba)(en)(H2O)]. These complexes were thoroughly characterized using spectral and analytical techniques, revealing an octahedral geometry for all. Coats–Redfern calculations indicated their non‐spontaneous nature yet highlighted their thermal stability. DNA binding studies unveiled a groove binding mode for the complexes, with intrinsic binding constants (Kb) and Stern–Volmer quenching constant (Ksq) supporting their strong binding capabilities. Nuclease activity against pBR322 was assessed through gel electrophoresis. Additionally, docking studies using AutoDock 4.2 software provided insights into their binding affinities. In terms of biological activities, the Cu complex demonstrated superior cytotoxicity and antibacterial and antifungal properties compared to the other ternary metal complexes. This suggests its potential for further exploration in biomedical applications. [ABSTRACT FROM AUTHOR]

ABSTRACT The current investigation involved the synthesis and detailed characterization of novel mixed‐ligand complexes of Mn(II) (MnDPPNPH) and Cu(II) (CuDPPNPH). These complexes incorporate 2,6‐di(1H‐pyrazol‐1‐yl)pyridine (DPP) and a Schiff base derived from 2‐hydroxy naphthaldehyde (NPH). The synthesized complexes revealed a stoichiometric ratio of 1:1:1 (metal:DPP:NPH), indicative of an octahedral coordination geometry around the Mn(II) and Cu(II) centers, as represented by the chemical formula [M (DPP)(NPH)(Cl)]. To elucidate their structural and electronic properties, theoretical calculations were performed. These calculations facilitated the optimization of the geometrical structures and provided insights into the molecular orbital characteristics of the complexes. The MnDPPNPH and CuDPPNPH complexes demonstrated potential phenoxazinone synthase mimicking activity by catalyzing aerial coupling of o‐aminophenol (OAPh) to form phenoxazine‐2‐one (phenox). The mimicking activity of these complexes was quantitatively assessed using Michaelis–Menten enzymatic kinetics. Various enzyme kinetics plots were employed to determine several kinetic parameters, including the specificity constant and turnover number (kcat), which are crucial for understanding the efficiency of the catalytic cycles. Remarkably, the synthesized MnDPPNPH and CuDPPNPH complexes exhibited significantly higher turnover numbers (kcat) compared to previously reported complexes. This finding suggests that these new complexes possess superior catalytic activity, highlighting their potential as effective catalysts for reactions mimicking the function of phenoxazinone synthase. [ABSTRACT FROM AUTHOR]

ABSTRACT Novel compounds with pharmacological activity were synthesized from Pd(II), Fe(III), Cr(III), Ni(II), and Cu(II) ions with 1‐cyclopropyl‐6‐fluoro‐4‐(2‐hydroxy‐phenylimino)‐7‐piperazin‐1‐yl‐1,4‐dihydro‐quinoline‐3‐carboxylic acid (CFAP). The ligand's NH and OH groups allowed it to interact with the metals as a neutral tridentate. The investigated novel compounds were described using 1H and 13C NMR spectra, FT‐IR spectrums, TGA and UV–Vis (conductance of molecules), and CHN‐analysis. Additionally, the pH profile of the CFAP complexes indicated great stability, and the complexes' stability constant was discovered in the solution. To extract important properties for CFAP and its complexes, computational research was used, CFAPCu, CFAPCr, CFAPNi, and CFAPFe have octahedral geometry, while CFAPPd has square planar geometry. To investigate the molecular geometry, density functional theory calculations (DFT) were carried out. The molar ratio and continuous fluctuation data confirmed that the (M:L) ratio was (1:1). In vitro tests were conducted to evaluate Schiff base's antimicrobial action ligand and its metal chelates against fungal and bacterial infections. The findings showed that the antimicrobial efficacy is as follows: When CFAPPd is compared to fluconazol and ofloxacin as reference medications, it is the highly inhibitor complex. The novel CFAP ligand and its complexes were investigated for In vitro carcinogenic potential against Hep‐G2, MCF‐7, and HCT‐116 cell lines. As compared to the medication vinblastine, the results once again demonstrated that CFAPPd is the most active agent. Moreover, the complexes demnstrated strong reactivity in capturing free radicals when their antioxidant activity was investigated. Viscosity, spectral investigations, and gel electrophoreses were used to identify the interaction between metal chelates and DNA. Every examined compound is shown to be an enthusiastic DNA binder by viscosity and spectrophotometric titration investigations. The heightened hydrophobic and electrostatic interactions between aromatic rings could be the cause of this. Ultimately, these compounds could be regarded as promising bioactive substances. [ABSTRACT FROM AUTHOR]

Two halogenated Schiff bases namely, (E)-1-(((2,6-dichlorophenyl)imino)methyl)naphthalen-2-ol (L1) and (E)-1-(((4-bromo-2,6-dichlorophenyl)imino)methyl)naphthalen-2-ol (L2) were synthesized and reacted with copper(II) nitrate trihydrate in ethanol to give Cu(L1)2 (1) and Cu(L2)2 (2). All the ligands and complexes were successfully characterized using FT-IR, UV-Vis, 1H & 13C-NMR as well as mass spectra and the purity was ascertained by elemental analysis. Electron paramagnetic resonance (EPR) was used to confirm the paramagnetic nature of 1 and 2. Furthermore, the single X-ray crystal structures of 1 and 2 were determined, confirming the formation of mononuclear species in which the Cu(II) center was bonded to two bidentate Schiff bases (L1 or L2) adopting a slightly distorted square planar geometry. Density Function Theory studies revealed that, complex 2 with lowest energy band gap (ΔE) of 2.49 eV is the most reactive among the compounds. α-Amylase and α-glucosidase assays were used to evaluate the antidiabetics potential of the compounds. Complexes 1 and 2 displayed very promising antidiabetic activities with IC50 values of 148.126 mM and 107.786 mM for α-amylase assay while it was 171.559 mM for acarbose (reference drug). The antioxidant potential of the compounds was investigated using nitric oxide (NO), ferric reducing ability power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays. The compounds showed moderate to good antioxidant activities with 1 and 2 having IC50 values of 100.044 mM and 247.463 mM for NO scavenging assay, which relatively surpass Vanillin with IC50 value of 466.626 mM. All the compounds showed poor to moderate results against Escherichia coli, Staphylococcus aureus, Bacillus substilis, and Pseudomonas aeruginosa. However, none of them were active against Klebsiella pneumoniae. Generally, 1 and 2 displayed better antidiabetes, antioxidant, and antibacterial potential than L1 and L2. Predicted physicochemical and pharmacokinetic properties of all the compounds showed minimal violation of Lipinski's Ro5. [ABSTRACT FROM AUTHOR]

The development of efficient synthetic strategies for the preparation of tetrasubstituted N−H pyrrole derivatives, especially in an environmentally benign fashion is important yet challenging. Herein, we report a copper(II)‐catalyzed tandem reaction involving 1,3‐dipolar cycloaddition of α,β‐ynones and glycine iminoesters, followed by copper(II)‐promoted oxidative (air) dehydrogenative aromatization, allowing de novo access to tetrasubstituted N−H pyrroles in up to 81 % yield under green reaction conditions. A possible reaction pathway is tentatively proposed. Finally, fully substituted pyrroles are available by N‐alkylation, and a preliminary phase‐transfer catalytic asymmetric N‐alkylation was also studied to give an axially chiral pyrrole. [ABSTRACT FROM AUTHOR]

We synthesised a sequence of structurally related copper(II) complexes of Schiff base ligands, 2-[(2-benzylamino-ethylimino)-methyl]-phenol [L1(H)], 2-[(2-benzylamino-ethylimino)-methyl]-4-methyl-phenol [L2(H)], and 2-[(2-benzylamino-ethylimino)-methyl]-4-bromo-phenol [L3(H)]. The complexes were characterized by ATR, UV-vis, EPR, ESI-MS, single crystal XRD, and elemental analyses. Based on the crystal structure, the ligand was coordinated to the copper(II) centre in a tridentate mode through phenolate(oxygen), imine nitrogen and amine nitrogen in an NNO fashion and the azide moiety served as an auxiliary ligand. Furthermore, we have investigated the antimicrobial activities of copper(II) complexes against clinically relevant fungal strains, including Candida albicans, Candida glabrata, and Candida tropicalis, as well as bacteria such as Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA), representing Gram-negative and Gram-positive pathogenic strains. Comparing the activity of complex 2 (128–512 μg mL−1) to complex 3 (64–128 μg mL−1), the latter demonstrated more potent effectiveness against all of the tested fungal strains. The activity of the complexes against MRSA reveals the inhibitory concentrations of 1024 μg mL−1 for 1, 128 μg mL−1 for 2, and 256 μg mL−1 for 3. It is worth mentioning that, at their minimum inhibitory concentrations (MICs), the complexes are not toxic to Galleria mellonella. Furthermore, the spot and broth microdilution assay results were in good agreement with the actual metabolic viability of bacterial and fungal strains, in which the complexes were active while having no effect on the metabolite resazurin. Additionally, in silico studies have been employed to elucidate both non-bonding interactions and the mode of action across protein sequences of experimentally studied microbes. The performance of complexes closely mirrored the reactivity order determined in in vitro studies. The impeding properties of complexes can be due to the dysfunctioning of virulent genes and signalling proteins and also affect the activities of transferase and transcriptase proteins. Overall, the complexes are promising candidates for antimicrobial drug development. We anticipate utilising these molecules for clinical purposes. [ABSTRACT FROM AUTHOR]

Abstract\nHIGHLIGHTSA new Schiff base inhibitor known as “N, N’ carbonyl- Bis (para-hydroxy benzaldehyde imine)” has been synthesized and characterized by FTIR, NMR, and UV-Visible spectroscopy, the molecule was then assessed for its ability to prevent copper from corroding in a solution of 0.5 M H2SO4 using potentiodynamic polarization, electrochemical impedance spectroscopy, scanning electron microscopy SEM combined with energy dispersion spectroscopy EDX, and atomic force microscopy AFM. The tested inhibitor exhibits good copper corrosion inhibition performance in a 0.5 M H2SO4 solution. As inhibitor concentration rises, inhibition performance also rises, reaching a maximum inhibitory efficacy of around 84.76 ± 0.69% at 5.10−4 M. The inhibitor was adsorbable to the metal surface and followed the Langmuir isotherm. It has been done such that the addition of KI increased the inhibitory effectiveness, the mixed additives worked together. There is good agreement between the conclusions drawn from theoretical calculations using DFT and MD simulation and actual observations.A new Schiff base inhibitor has been synthesized.The inhibitory efficiency increase with increasing inhibitor concentration.The investigated molecule adsorbs on the copper surface through active centers like N and O.The synthesized molecule has good inhibitory effectiveness with respect to copper corrosion in an acidic medium.A new Schiff base inhibitor has been synthesized.The inhibitory efficiency increase with increasing inhibitor concentration.The investigated molecule adsorbs on the copper surface through active centers like N and O.The synthesized molecule has good inhibitory effectiveness with respect to copper corrosion in an acidic medium. [ABSTRACT FROM AUTHOR]

Mono- and binuclear Cu(I) complexes were isolated employing 2,1,3-benzoselenadiazole (BSeD) as the N-donor ligand, and triphenylphosphine or bis[(2-diphenylphosphino)phenyl] ether (DPEphos) as P-donors. Then, 77Se NMR was measured for the free ligand and the corresponding Cu(I) derivatives, and the related signal was downshifted by 12.86 ppm in the case of [Cu(BSeD)(PPh3)2(ClO4)], and around 15 ppm for the binuclear species. The structure of [Cu(BSeD)(PPh3)2(ClO4)] and [Cu2(μ2-BSeD)(DPEphos)2(ClO4)2] was confirmed by single-crystal X-ray diffraction. The geometry of the Cu(I) complexes was optimized through DFT calculations, and the nature of the Cu···O interaction was investigated through AIM analysis. The three Cu(I) complexes were characterized by intense absorption under 400 nm and, after being excited with blue irradiation, [Cu(BSeD)(PPh3)2(ClO4)] and [Cu2(μ2-BSeD)(PPh3)4(ClO4)2] exhibited weak red emissions centered at 700 nm. The lifetimes comprised between 121 and 159 μs support the involvement of triplet excited states in the emission process. The photoluminescent properties of [Cu(BSeD)(PPh3)2(ClO4)] were supported by TDDFT computations, and the emission was predicted at 710 nm and ascribed to a metal-to-ligand charge transfer (3MLCT) process, in agreement with the experimental data. [ABSTRACT FROM AUTHOR]

Two copper (II) complexes based on the mixed ligand system were synthesized and structurally characterized. The molecular formulae for complex (1), [Cu2L1L′] and complex (2), [CuL2L′] were determined based on analytical data, molar conductance, and thermal analysis results. The optimized structures of complexes (1) and (2) were determined by magnetic and spectroscopic measurements (FTIR, UV–Vis, and ESR) and confirmed by processing powder X‐ray diffraction data by Expo 2014 software. The geometry index (τ5), determined by ESR spectra and structural analysis based on powder X‐ray, demonstrates the square pyramidal geometry of the Cu (II) center of [Cu2L1L′] and [CuL2L′]. Cyclic voltammetry measurements were performed to elucidate the relationship between the redox properties of (1) and (2) and their oxidase‐mimicking catalytic activity. Catalytic aerobic oxidation of the polyphenols 3,5‐di‐tert‐butylcatechol (3,5‐DTBCH2), 4‐nitrocatechol, and 2‐aminophenol (2‐APH3) was studied by stopped‐flow technique. Promising catechol oxidase (COX) and phenoxazinone synthase (PHS) mimetic activity have been demonstrated for (1) and (2). Electrochemical data were used to determine the free energy (ΔG°) or driving force (−λ), and their correlation with the oxidase mimetic activity of(1) and (2) was examined. Several experimental procedures have been performed that have helped describe the catalytic mechanisms of the catalytic reactions taking place. [ABSTRACT FROM AUTHOR]

AbstractA Schiff base (imine) ligand, (E)-4-((2-hydroxy-3,5-diiodobenzylidene)amino)-N-(4,6-dimethylpyrimidin-2-yl)benzenesulfonamide (HL), was synthesized by condensation of 3,5-diiodosalicylaldehyde with sulfamethazine. The ligand was then complexed with Zn(II), Cu(II), Ni(II), Co(II) and Fe(II) employing a metal to ligand ratio of 1:2 to form chelates (1-5), [M(L)2(H2O)2]. Characterization was done by UV-visible, FTIR, 1H and 13C NMR spectroscopy, elemental analysis, magnetic moments, thermogravimetric analyses (TGA) and conductance studies. The Schiff base behaved as a bidentate ligand and metal chelates assumed octahedral geometry. MOE-docking was employed to assess binding of the Schiff base (HL) and its chelates (1-5) with 1T2P, 1VVQ, 2W61, 3U2D, 4H8E and 5K18 proteins. Results indicated that Zn(II) chelate (1) and Fe(II) chelate (5) are the most potent compounds. Antibacterial and antibiofilm activities were executed against Enterococcus faecalis, Staphylococcus aureus, Proteus mirabilis and Klebsiella pneumoniae. Antifungal activities were performed against Candida albicans and Aspergillus niger. The Schiff base exhibited moderate antibacterial/antifungal activities that were enhanced on chelation with metal ions. Zinc(II) chelate (1) and Fe(II) chelate (5) show excellent antibacterial/antifungal activities. Complex 2 exhibited good antibiofilm activity. [ABSTRACT FROM AUTHOR]

DNA being the necessary element in cell regeneration, controlled cellular apoptosis via DNA binding/cleaving is considered an approach to combat cancer cells. The widely prescribed metallodrug cisplatin has shown interactions with the guanine-N7 center, and a plethora of complexes are continually developed to enhance crosslinking properties as well as covalent and non-covalent interactions. Two pentadentate ligands, L1 (1-(6-(1H-benzo[d]imidazol-2-yl)pyridin-2-yl)-N,N-bis(pyridin-2-ylmethyl)methanamine) and L2 (1-(6-(1-methyl-1H-benzo[d]imidazol-2-yl)pyridin-2-yl)-N,N-bis(pyridin-2-ylmethyl)methanamine), were synthesized together with their respective copper(II) complexes [1](ClO4)2 and [2](ClO4)2, which crystallized in a trigonal bipyramidal fashion. Different analytical and spectroscopic methods confirmed their formation, and their redox behaviour was also examined. The interactions of salmon sperm DNA (ss-DNA) with these two complexes were explored using absorbance spectroscopy, and they both exhibited a binding affinity (Kb) of ∼104 M−1. Fluorescence quenching experiments with ethidium bromide (EB)-bound DNA (EB–DNA) were also performed, and Stern–Volmer constant (KSV) values of 6.93 × 103 and 2.34 × 104 M−1 for [1](ClO4)2 and [2](ClO4)2, respectively, were obtained. Furthermore, DNA conformational changes due to the interactions of both complexes were validated via circular dichroism. We also assessed the DNA cleavage property of these complexes, which resulted in the linearization of circular plasmid DNA. This finding was supported by studying the growth of MDA-MB-231 breast cancer cells upon treatment with both Cu(II) complexes; IC50 values of 5.34 ± 1.02 μM and 0.83 ± 0.18 μM were obtained for [1](ClO4)2 and [2](ClO4)2, respectively. This validates their affinity towards DNA, and these insights can be further utilized for non-platinum based economical metallodrug development based on first row transition metals. [ABSTRACT FROM AUTHOR]

In this study five different complexes of Cu(II) were synthesized for the purpose of environmentally notorious mercury sensing and preliminary biological screening. Pyridine‐2,6‐dicarboxylic acid (also known as dipicolinic acid, and abbreviated as H2DPA), 3‐phenyl pyrazole (3‐ppz), 4‐iodo‐1H‐pyrazole (4‐ipz), 4‐nitropyrazole (4‐npz), 4‐bromopyrazole (4‐bpz), and 4‐chloropyrazole (4‐cpz) were chosen as potential ligands. The synthesized complexes labelled as 1–5, namely [Cu(DPA)(3‐ppz)], [Cu(DPA)(4‐ipz)], [Cu(DPA)(4‐npz)], [Cu(DPA)(4‐bpz)], [Cu(DPA)(4‐cpz)], were proposed based on spectroscopic data (FTIR, TGA, and UV‐visible spectroscopy). These complexes feature C=O functionalities that are not involved in coordination and may be used for further applications. The isolated complexes were utilized for detecting Hg(II) ions in water samples. Various concentrations of Hg(II) ions were prepared for detection purposes, and changes in absorption concerning complexes 1–5 were determined using UV‐Visible spectroscopy. It was found that complexes 3 and 4 exhibit efficient sensing abilities towards Hg(II) ions. The antibacterial activities of complexes 1–5 were assessed against S. typhi and E. coli. The complexes 1 and 3 displayed good antibacterial activities against S. typhi (13.67, and 13.56 mm, respectively) while complexes 1, 2 and 4 were found to be efficient against E. coli (11.6, 12.66, 11.31 mm, respectively). The absorption maxima of 2,2‐diphenyl‐1‐picryhydrazyl (DPPH) at 517 nm, considerably shifted upon addition of complexes 1–5. The results reveal that the complexes possess potential free radical scavenging abilities. [ABSTRACT FROM AUTHOR]

In the present era, the fixation of atmospheric CO2 is of significant importance and plays a crucial role in maintaining the balance of carbon and energy flow within ecosystems. Generally, CO2 fixation is carried out by autotrophic organisms; however, the scientific community has paid substantial attention to execute this process in laboratory. In this report, we synthesized two carbonato-bridged trinuclear copper(II) complexes, [Cu3(L1)3(μ3-CO3)](ClO4)3 (1) and [Cu3(L2)3(μ3-CO3)](ClO4)3 (2) via atmospheric fixation of CO2 starting with Cu(ClO4)2·6H2O and easily accessible pyridine/pyrazine-based N4 donor Schiff base ligands L1 and L2, respectively. Under very similar reaction conditions, the ligand framework embedded with the phenolate moiety (HL3) fails to do so because of the reduction of the Lewis acidity of the metal center, inhibiting the formation of a reactive hydroxide bound copper(II) species, which is required for the fixation of atmospheric CO2. X-ray crystal structures display that carbonate-oxygen atoms bridge three copper(II) centers in μ3syn–anti disposition in 1 and 2, whereas [Cu(HL3)(ClO4)] (3) is a mononuclear complex. Interestingly, we also isolated an important intermediate of atmospheric CO2 fixation and structurally characterized it as an anti–anti μ2 carbonato-bridged dinuclear copper(II) complex, [Cu2(L2)2(μ2-CO3)](ClO4)2·MeOH (2-I), providing an in-depth understanding of CO2 fixation in these systems. Variable temperature magnetic susceptibility measurement suggests ferromagnetic interactions between the metal centers in both 1 and 2, and the results have been further supported by DFT calculations. The catalytic efficiency of our synthesized complexes 1–3 was checked by means of catechol oxidase and phenoxazinone synthase-like activities. While complexes 1 and 2 showed oxidase-like activity for aerobic oxidation of o-aminophenol and 3,5-di-tert-butylcatechol, complex 3 was found to be feebly active. ESI mass spectrometry revealed that the oxidation reaction proceeds through the formation of complex–substrate intermediations and was further substantiated by DFT calculations. Moreover, active catalysts 1 and 2 were effectively utilized for the base-free oxidation of benzylic alcohols in the presence of air as a green and sustainable oxidant and catalytic amount of TEMPO in acetonitrile. Various substituted benzylic alcohols smoothly converted to their corresponding aldehydes under very mild conditions and ambient temperature. The present catalytic protocol showcases its environmental sustainability by producing minimal waste. [ABSTRACT FROM AUTHOR]

A thiophene-derived Schiff base ligand (E)-2-morpholino-N-(thiophen-2-ylmethylene)ethanamine was used for the synthesis of M(II) complexes, [TEM(M)X2] (M = Co, Cu, Zn; X = Cl; M = Cd, X = Br). Structural characterization of the synthesized complexes revealed distorted tetrahedral geometry around the M(II) center. In vitro investigation of the synthesized ligand and its M(II) complexes showed considerable anti-urease and leishmanicidal potential. The synthesized complexes also exhibited a significant inhibitory effect on urease, with IC50 values in the range of 3.50–8.05 μM. In addition, the docking results were consistent with the experimental results. A preliminary study of human colorectal cancer (HCT), hepatic cancer (HepG2), and breast cancer (MCF-7) cell lines showed marked anticancer activities of these complexes. [ABSTRACT FROM AUTHOR]

Background: The ineffectiveness of treatments for infections caused by biofilm-producing pathogens and human carcinoma presents considerable challenges for global public health organizations. To tackle this issue, our study focused on exploring the potential of synthesizing new complexes of Co(II), Cu(II), Ni(II), and Zn(II) with sorbic acid to enhance its antibacterial, antibiofilm, and anticancer properties. Methods: Four novel complexes were synthesized as solid phases by reacting sorbic acid with Co(II), Cu(II), Ni(II), and Zn(II). These complexes were characterized by various technique, including infrared spectra, UV–Visible spectroscopy, proton nuclear magnetic resonance (1H NMR), and thermal analysis techniques, including thermogravimetry (TG). Results: The data acquired from all investigated chemical characterization methods confirmed the chemical structure of the sorbate metal complexes. These complexes exhibited antibacterial and antibiofilm properties against both Gram-positive and Gram-negative bacteria. Furthermore, these complexes enhanced the antibacterial effects of commonly used antibiotics, such as gentamicin and imipenem, with fractional inhibitory concentration (FIC) indices ≤ 0.5. Notably, the Cu(II) complex displayed the most potent antibacterial and antibiofilm activities, with minimum inhibitory concentration (MIC) values of 312.5 µg/mL and 625.0 µg/mL for Bacillus cereus and Escherichia coli, respectively. Additionally, in vitro assays using the methyl thiazolyl tetrazolium (MTT) method showed inhibitory effects on the growth of the human colon carcinoma cell line (HCT-116 cells) following treatment with the investigated metal complexes. The IC50 values for Co(II), Cu(II), Zn(II), and Ni(II) were 3230 µg/mL, 2110 µg/mL, 3730 µg/mL, and 2240 µg/mL, respectively. Conclusion: Our findings offer potential for pharmaceutical companies to explore the development of novel combinations involving traditional antibiotics or anticancer drugs with sorbate copper complex. [ABSTRACT FROM AUTHOR]

A facile synthetic protocol was employed to synthesize new coumarin Schiff base (E)-3-(1-((2-hydroxy-5-methylphenyl)imino)ethyl)-2H-chromen-2-one] and their Co and Cu metal complexes. Synthesized molecules were characterized by various spectroscopic methods. The results of antibacterial studies demonstrated that the maximum level of growth inhibition for S. aureus and B. subtilis was shown by compound 5, with inhibition zones of 16±1 mm and 18.5±1.3 mm, respectively, while, Compound 4 exhibited 12.5±0.5 mm and 14±0.25 mm, respectively. Invitro Cytotoxicity of Cu-complex 5 towards human hepatocellular adenocarcinoma cancer cells, at concentrations of 12.5, 25, 50, and 100 g/mL, displayed a reduction in the percentage of cell viability in a dose-dependent manner, with values of 72.45%, 60.12%, 48.69%, and 23.25%, respectively. The results revealed that Compound 5 has the potential to interact with the bacterial membrane surface, leading to the disruption of the same. Additionally, potentiometric analysis was used to estimate the proton-ligand dissociation constant of HL as well as its metal stability constants with Co2+ and Cu2+. [ABSTRACT FROM AUTHOR]

Selective oxidation of alcohols towards carbonyl‐based products, such as aldehydes, is a subject of significant interest in the field of catalysis. Herein, a Zn‐based MOF with 2‐methylimidazolate linker (ZIF‐8) is modified and introduced as catalysts in a selective oxidation of alcohol with benzyl alcohol as the model of the reaction. Modification of ZIF‐8 includes the inclusion of Co(II), Cu(II) or Ni(II) ions as partial replacements for the original Zn(II) metal ions during the synthesis process. The resulting modified ZIF‐8 displays similar PXRD patterns to that of ZIF‐8, indicating no alteration of structures after the introduction of Co(II), Cu(II) or Ni(II) ions. However, the addition of Co(II) was found to modify the resulting ZIF‐8 composition to a higher extent compared to that of Cu(II) and Ni(II) ions. The catalytic test of benzyl alcohol oxidation was performed in a solvent‐free condition with TBHP as the oxidant. Reaction optimization includes reaction temperature, mass of catalysts, TBHP concentration, and reaction time. Among all the catalysts employed in the oxidation of benzyl alcohol, Co(II)‐ and Cu(II)‐modified ZIF‐8 show the highest catalytic activity with 64 % and 62 % conversion, respectively. Furthermore, the catalyst leaching and recyclability tests show that the reactions proceed in heterogeneous systems. [ABSTRACT FROM AUTHOR]

A simple, sensitive, and rapid spectrophotometric method for the determination of Cu(II), Ni(II), Co(II), and Mn(II) ions is proposed based on the complexation of metal ions with a synthesized ligand, 4-methylpiperazine dithiocarbamic acid, formed by the reaction of 4-methyl piperazine and carbon disulfide under cold conditions. The colored complex formed by the reaction of the synthesized ligand with these heavy metals in an aqueous acetonitrile medium exhibits absorbance maxima at 435, 395, 370, and 495 nm for Cu, Ni, Co, and Mn metals, respectively. Beer's law was valid within concentration ranges of 0.34–20.46, 0.49–39.81, 0.47–38.07, and 0.49–11.03 µg/mL for Cu, Ni, Co, and Mn, respectively. Various reaction parameters such as pH, volume of reagent, and solvents were carefully studied and optimized. The limits of detection and limits of quantification for Cu, Ni, Co, and Mn were found to be 1.4, 2.4, 1.1, and 1.1 µg/mL and 4.2, 7.2, 3.3, and 3.3 µg/mL, respectively. The method proved to be sensitive and rapid, requiring only a few minutes for sample analysis. The synthesized ligand and metal(II) 4-methyl piperazine dithiocarbamate complexes, M(4-methylPzdtc)2, were characterized by FTIR. The method was subsequently applied to vegetable and water samples spiked with the cations. The high recoveries of Cu, Ni, Co, and Mn from the proposed method indicate good accuracy and precision. [ABSTRACT FROM AUTHOR]

1‐Formyl‐3‐semicarbazide (FSC, HL) and its metal complexes with Co(II), Cu(II), Zn(II), and Cd(II) ions have been synthesized and characterized by elemental analysis, liquid chromatography‐mass spectrometry (LC–MS), infrared (IR), electronic, nuclear magnetic resonance (NMR) and electron spin resonance (ESR) spectroscopy, thermogravimetric analysis (TGA), magnetic susceptibility, and conductivity measurements. The chelates are non‐electrolytic in nature with distorted octahedral geometry. The kinetic and thermodynamic properties were calculated using the Coats–Redfern relation results in positive enthalpy change values and negative entropy change values. The equilibrium studies of FSC with Co(II), Zn(II), and Cd(II) ion have been carried out by potentiometric pH titrations in 70% v/v DMF‐water medium at 303 K and 0.1 M (KNO3) ionic strength. The study revealed that FSC is monobasic acid with pKa value of 8.84. The stability constants suggested the formation of 1:1 Co(II)‐FSC complex, and Zn(II)‐FSC and Cd(II)‐FSC systems revealed the formation of both 1:1 and 1:2 complexes in the solution. DNA binding studies for the metal chelates have been carried out using electronic absorption spectra, fluorescence emission spectra, and viscosity measurements revealing groove binding for Co(II), and Zn(II) complexes, and intercalation mode of binding for Cu(II)‐FSC complex with CT‐DNA. The Kb values from absorption studies are Co(II)‐FSC = 0.9990 × 102, Cu(II)‐FSC = 2.433 × 104, and Zn(II)‐FSC = 8.277 × 102 M−1, and the KSV values from the competitive fluorescence emission studies are Co(II)‐FSC = 0.19212 and Cu(II)‐FSC = 0.11482 M−1. Molecular docking carried out for both ligand and its Co(II) and Zn(II) complexes also revealed groove mode of binding, and Cu(II) complex showed intercalative mode of binding. The inhibition constants for HL, Co(II), Cu(II), and Zn(II) are 1460, 0.478, 0.122, and 0.194 μM, respectively. The antimicrobial activity has been studied using agar disk diffusion method against Escherichia coli and Bacillus subtilis. FSC has been found to be more active against gram +ve and gram –ve bacteria than its metal chelates. [ABSTRACT FROM AUTHOR]

A novel 8-hydroxy quinoline-derived amide receptor, in conjunction with its Cu (II) and Zn (II) complexes, has been strategically developed to function as remarkably efficient fluorescent receptors with a distinct capability for anion sensing. The comprehensive characterization of the synthesized compounds were achieved through UV-Vis, IR, NMR, and HRMS spectroscopic techniques. Among the Cu (II) and Zn (II) complexes, the latter exhibits superior selectivity for anions, specifically dihydrogen phosphate and hydrogen sulfate, as their tetrabutylammonium salts in a 9:1 acetonitrile-water (v/v) mixture. The Cu (II) complex demonstrates enhanced anion binding compared to the amide ligand, albeit with reduced selectivity. Furthermore, the affinity was evaluated using the Benesi-Hildebrand plot. The binding constants and Limit of Detection (LOD) for both complexes were precisely quantified. The Job plot illustrates a clear 1:1 binding interaction between the metal complexes and the guest anions. Significantly, both metal-complex receptors display a broad spectrum of antibacterial activity, against both gram-positive and gram-negative bacteria. It is worth highlighting that the Zn (II) complexed receptor outperforms the Cu (II) complexed receptor, as evidenced by its considerably lower Minimum Inhibitory Concentration (MIC) value against both bacterial strains. [ABSTRACT FROM AUTHOR]

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]

This study presents fibers based on methacrylic acid–methyl methacrylate (Eudragit L100) as Cu(II) adsorbents, resulting in antimicrobial complexes. Eudragit L100, an anionic copolymer synthesized by radical polymerization, was electrospun in dimethylformamide (DMF) and ethanol (EtOH). The electrospinning process was optimized through a 22-factorial design, with independent variables (copolymer concentration and EtOH/DMF volume ratio) and three repetitions at the central point. The smallest average fiber diameter (259 ± 53 nm) was obtained at 14% w/v Eudragit L100 and 80/20 EtOH/DMF volume ratio. The fibers were characterized using scanning electron microscopy (SEM), infrared spectroscopy in attenuated total reflectance mode (FTIR-ATR), and differential scanning calorimetry (DSC). The pseudo-second-order mechanism explained the kinetic adsorption toward Cu(II). The fibers exhibited a maximum adsorption capacity (qe) of 43.70 mg/g. The DSC analysis confirmed the Cu(II) absorption, indicating complexation between metallic ions and copolymer networks. The complexed fibers showed a lower degree of swelling than the non-complexed fibers. The complexed fibers exhibited bacteriostatic activity against Gram-negative (Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria. This study successfully optimized the electrospinning process to produce thin fibers based on Eudragit L100 for potential applications as adsorbents for Cu(II) ions in aqueous media and for controlling bacterial growth. [ABSTRACT FROM AUTHOR]

Mononuclear copper(II) complex [Cu(DBDACH)2](ClO4)2 (1) was synthesized with a cyclohexane-1,2-diamine-based bidentate ligand, N,N'-dibenzyl 1,2-diaminocyclohexane (DBDACH) and characterized by various spectroscopic techniques. The structure of the complex was determined by single-crystal X-ray analysis and shows a distorted square planar geometry around the copper center. DNA binding interactions were interrogated by UV-Vis spectroscopic titration, circular dichroism, and docking studies. These studies confirmed that the copper complex binds with CT-DNA through minor groove interactions and showed a good binding constant of Kb = 2.15 × 104 M−1. The catecholase-like activity of 1 was investigated with model substrate 3,5-di-tert-butylcatechol (3,5-DTBC) to corresponding 3,5-di-tert-butylquinone (3,5-DTBQ) using UV-Vis spectroscopy. The rate of this reaction is 0.89 × 10−3 s−1. The kinetic characteristics of 1 were determined through the Michaelis–Menten equation and a Lineweaver-Burk analysis, yielding Vmax (3.4 × 10−3 M s−1), kM (0.49 × 10−3 M), and kcat (1.45 × 10−2 s−1). [ABSTRACT FROM AUTHOR]

The incidence of multi-resistant infections has sharply increased. One of the best strategies for developing new drugs is re-engineering existing drugs to enhance their bioavailability and antimicrobial activities. The latest systems focus on designing bioinorganic platforms to develop antimicrobial agents to target drug-resistant microbial strains. Various literature reports highlight metal-based antimicrobial agents unveiling an innovative strategy to tackle microbial agents. One of the significant mechanisms of antibiotic resistance in bacteria is the impermeability of its cell membrane towards antibiotics. Antibiotic-based Schiff base complexes are prime candidates for drug design with minor side effects in this scenario. The enhanced activity of antibiotic Schiff base complexes over their parent compound plays a key role in the emergence of innovative antimicrobials. In this review, we highlight the biological potential aspects of some selected antibiotic-based Schiff base complexes of penicillin, cephalosporins, quinolones, and sulfonamides. Some of the bacteria, especially P. aeruginosa, remain resistant to most of the commercially available antibiotics. Here, the review highlights that Schiff base complexes mediated by antibiotics demonstrate bactericidal activity against these resistant strains. Additionally, their mode of action on the bacterial cell is highlighted. The increased activity of copper, zinc, and silver complexes of different Schiff bases is attributed to their inherent redox chemistry. [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]

Newly synthesized ligand 2-(2- acetamidophenyl)-2-oxo-N-(pyridin-2-ylmethyl)acetamide and its copper(II) complex were characterized by elemental analyses, FT-IR, UV–Vis., ESR, 1H-NMR, and thermal analysis along with the theoretical quantum chemical studies. Combined experimental and theoretical DFT (density functional theory) studies showed the ligand to be a tridentate ligand with three coordinate bonds. The complex was suggested to be in a distorted octahedral structure with dx2-y2 ground state. The activation energy, ΔE*; entropy ΔS*; enthalpy ΔH* and order of reaction has been derived from differential thermogravimetric (DTA) curve, using Horowitz–Metzeger method. The nujol mull electronic spectrum of the ligand and Cu(II) complex have been recorded and the difference of the excited and ground state densities has also been theoretically calculated and plotted to investigate the movement of electrons on excitation. The Cu(II) complex was evaluated for its antibacterial activity against two bacterial species, namely Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Antifungal screening was performed against two species (Condida albicans and Aspergillus flavus). The complex under investigation was found to possess notable biological activity. Molecular docking investigation predicted different types of non-covalent interactions of the synthesized ligand towards Insulin-like growth factor 1 receptor (ID: 5FXR). [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]

This article focused on the preparation of Cu, Co (II)‐containing linoleic‐based poly(ester amide) resin and studied their use as new binders for paint formulation. The metal‐containing LPEA was carried out by in situ condensation polymerization reaction between hydroxyethyl linoleic fatty amide diol (HELA), phthalic anhydride (PA), and Cu, Co acetate. The structure of the prepared resins was confirmed by FTIR and 1H NMR spectral studies. Physicochemical, thermal analysis (TGA), surface morphology (SEM), and elemental composition (EDX) were studied by standard methods. The physicomechanical, antimicrobial, and corrosion/chemical resistance performance tests were also conducted to evaluate their coating properties. These studies revealed that (i) the incorporation of Cu, Co (II) has a significant influence on structural and physicochemical aspects. The paint formulation based on Cu, Co (II) containing LPEA showed very good results according to the corrosion resistant test evalution. (iii) Antimicrobial tests of all prepared resins were performed by agar diffusion method against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Klebsiella pneumonia, and pathogenic fungal strain using standard controlled medication, ciprofloxacin/fluconazole for the comparison. (iv) Cu, Co (II) containing LPEA serve as novel binders and promising candidates for use as binders for protective coating material. [ABSTRACT FROM AUTHOR]

Four complexes of essential metal ions, Cu(II) and Ni(II), with the new sulfonamide ligand N-(pyridin-2-ylmethyl)quinoline-8-sulfonamide (HQSMP) were synthesized and physicochemically and structurally characterized. Complex [Cu(QSMP)Cl]n (2) consists of a polymeric chain formed by distorted square pyramidal units. In 2, the sulfonamide ligand acts as a bridge coordinating to one Cu(II) through its three N atoms and to another metal ion via one O atom in the sulfonamido group, while the pentacoordinate complex [Cu(QSMP)(C6H5COO)] (3) presents a highly distorted square pyramidal geometry. Complex [Ni(QSMP)(C6H5COO)(CH3OH)][Ni(QSMP)(CH3COO)(CH3OH)] (4) consists of two mononuclear entities containing different anion coligands, either a benzoate or an acetate group. Both units exhibit a distorted octahedral geometry. The interaction of the complexes with CT-DNA was studied by means of UV-Vis and fluorescence spectroscopy, interestingly revealing that the Ni(II) complex presents the highest affinity towards the nucleic acid. Complexes 1 and 2 are able to cleave DNA. Both compounds show promising nuclease activity at relatively low concentrations by mediating the production of a reactive oxygen species (ROS). The interaction of the four complexes with bovine serum albumin (BSA) was also investigated, showing that the compounds can bind to serum proteins. The antitumor potential of complexes 1 and 2 was evaluated against the A549 lung adenocarcinoma cell line, revealing cytotoxic properties that were both dose- and time-dependent. [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 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]

A novel adsorbent (MIL-CMIVSB) was fabricated by modification of H2N-MIL-101(Cr) with carboxymethyl-imidazolium O-vanillin Schiff base. The MIL-CMIVSB's physicochemical characteristics were examined using the pertinent characterization methods. NH2-MIL-101(Cr) has a BET surface area of 1492.4 m2g−1, while MIL-CMIVSB adsorbent had 1278.7 m2g−1. Batch adsorption experiments examined the MIL-CMIVSB's cupric ion adsorption capacity from aqueous solutions at different adsorbent doses (0.1–3 mg), pH (2.0–10.0), contact times (0–240 min), metal ion initial concentrations (10–300 mg/L), and temperatures (298–308 K). The optimum conditions were 1 mg/mL of MIL-CMIVSB adsorbent, 46 min adsorption time, pH 7, 100 ppm initial cupric ion concentration, and 303 K temperature. MIL-CMIVSB effectively and selectively removes cupric ions with an adsorption capability of 359.05 ± 12.06 mg/g. The nonlinear Liu isotherm governed Cu(II) sorption performance on MIL-CMIVSB (KL = 0.257 ± 0.01 mg/g, R2 = 0.99892) and pseudo-2nd-order kinetically (k2 = 0.00116 × 10−4 g/mg min, R2 = 0.99721). [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]

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]