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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]

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]

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]

Three new trinuclear complexes containing either nickel(II), copper(II) or zinc(II), [Ni3L2(NO3)2(CH3OH)2]·2CH3OH (1), [Cu3Br2L2] (2), [Zn3L2(NCS)2(CH3OH)2]·0.5CH3OH·0.5H2O (3), and a new dioxidomolybdenum(VI) complex, [MoO2L] (4), have been prepared from the bis-Schiff base N,N'-bis(4-bromosalicylidene)-1,3-propanediamine (H2L) with various metal salts in methanol. The complexes were characterized by elemental analysis, IR and UV–Vis spectra. Molecular structures were confirmed by single crystal X-ray diffraction experiments. The Ni ions in 1 adopt an octahedral coordination environment, bridged by phenolate oxygen and nitrate ligands. The Cu ions in 2 are square pyramidal and square planar, and the Zn ions in 3 are square pyramidal and octahedral. The metal atoms in 2 and 3 are bridged by phenolate oxygen donors. The Mo ion in 4 is octahedral. The Schiff base ligand coordinates to the metal atoms through two phenolate O and two imino N donors. Biological assays revealed that the nickel and copper complexes have effective urease inhibition. [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]

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]

Two sulfoxide-containing Schiff bases, (E)-(((2-(methylsulfinyl phenyl) imino)methyl)-4-nitrophenol (HL1) and (E)-3,5-dibromo-2-(((2-(methylsulfinyl phenyl)imino)methyl)phenol (HL2), were prepared by condensation and subsequent oxidation reactions. In the presence of triethylamine, reactions of HL1 with 0.5 equivalent of copper acetate, cobalt acetate, nickel acetate and zinc acetate in ethanol afforded four metal complexes: (η2-N,O-L1)Cu(η3-O,N,O-L1) (1) and (η3-O,N,O-L1)2M (M = Co, 2; Ni, 3; Zn, 4), respectively. Similarly, treatment of HL2 with 0.5 equivalent of cobalt acetate and nickel acetate obtained two cobalt/nickel complexes: (η3-O,N,O-L2)2M (M = Co, 5; Ni, 6). Reactions of HL1 and one equivalent of Ru(PPh3)3Cl2 in tetrahydrofuran in the presence of triethylamine afforded a ruthenium(II) complex, (η3-O,N,S-L1)Ru(PPh3)2Cl (7). The molecular structures of HL1 and 1-7 have been confirmed by single-crystal X-ray diffraction. In addition, the UV–Vis, infrared, and fluorescence spectroscopies of 1–7 along with their electrochemical properties were also investigated. [ABSTRACT FROM AUTHOR]

In this investigation, six new metal complexes with 2-(pyridin-2-yl)benzo[d]imidazole (bpm) were synthesized and analyzed by single-crystal X-ray diffraction (XRD), including catena-bis[(µ-2,2-bis(4-carobxyphenyl)hexafluoropropane)-(2-(pyidin-2-yl)-1H-benzimidazole)-aqua-zinc] (1), catena-[(µ-2,2-bis(4-carobxyphenyl)hexafluoropropane)-(2-(pyidin-2-yl)-1H-benzimidazole)-aqua-cadmium] (2), aqua-[2,2-bis(4-carobxyphenyl)hexafluoropropane]-bis[2-(pyridin-2-yl)-1H-benzimidazole]-manganese (3), μ-[2-nitrobenzene-1,4-dicarboxylato]-μ-[2-nitrobenzene-1,4-dicarboxylato]-bis[2-(pyridin-2-yl)-1H-benzimidazole]-di-zinc (4), catena-[bis(µ-2-nitrobenzene-1,4-dicarboxylato)-diaqua-bis(2-(pyridin-2-yl)-1H-benzimidazole)-di-cadmium] (5), aqua-[pyridine-2,6-dicarboxylato]-[2-(pyridin-2-yl)-1H-benzimidazole]-copper hydrate (6) (H2hfipbb = 2,2-bis(4-carboxyphenyl)hexafluoropropane, H2nbdc acid = Nitroterephthalic acid, and H2pda = 2,6-pyridinedicarboxylic acid). Complex 1 crystallized in a monoclinic system with space group P21/n; 2 crystallized in a monoclinic system with space group C2/c; 3 crystallized in an orthorhombic system with space group Pna21; 5 crystallized in a monoclinic system with space group P21/c; 4 and 6 crystallized in triclinic systems with space group P-1. The DNA-binding modes of the complexes were investigated by several analysis methods (e.g. viscosity analysis, circular dichroism spectroscopy, fluorescent spectroscopic analysis, as well as UV spectroscopic analysis). Complexes 1-6 bind to calf thymus DNA via an intercalative mode. The results of this study provide insights into the mechanism of DNA binding and provide a basis for rationally designing new powerful reagents for DNA detection and targeting. [ABSTRACT FROM AUTHOR]

Antimicrobial and antituberculosis activities of transition metal complex Cu(I) and Cu(II) from salicylhydrazone of anthranihydrazide (HL1) have been theoretically investigated using DFT methods at ωB97XD, PBEPBE, MPW1PW91, HSEH1PBE, CAM-B3LYP/6-311++G(d,p) level of theory. Owing to the fact that microbial and tuberculosis attacked still prevail despite studies reported in the literatures. This study utilized a higher theoretical model to unravel necessary information about the possible application of the HL1 and its complexes as a potential drug candidate. The results obtained reveal that the ligand (HL1) had the higher energy gap for the HES and MPW whereas, it Cu(II) complex had the least energy gap making it more reactive in the biological environment compared to its counterpart. The Natural Bond orbital (NBO) analysis reveals molecular interactions are of four kinds; LP→BD*, LP→LP*, LP*→BD*, BD*→BD*, and BD*→LP* where the higher perturbation energy was observed from BD*(C2-C3) → BD*(C4- 5) with the energy of 231.74 kcal/mol. The vibration analysis shows that the studied complexes have 32 atoms and 90 normal modes, with 20 symmetric, 7 asymmetric, 31 bending, and 32 ring torsional distribution. And their theoretical wavelength of absorption was observed to be in good agreement with experimental reported values. Cu(II) was observed with the highest dipole moment and first-order hyperpolarizability (βtotal) with corresponding values of 9.30D and 19.268 which shows its can be good for medicinal application. Molecular docking screening showed that the ligand and its complexes have better antimicrobial activities compared to antituberculosis. [ABSTRACT FROM AUTHOR]

New transition metal complexes of cobalt(II), nickel(II), copper(II) and zinc(II) with new Schiff base [HLp] derived from pyrene-1-carbaldehyde and 4-Amino-3-mercapto-5-oxo-1,2,4-triazine were synthesized and characterized by elemental analysis, 1H-NMR, FT-IR, UV-Visible, ESR spectral studies, magnetic moment measurements and cyclic voltammetry. Results prove that [HLp] acts as bidentate ligand. Low conductance data reveal non-electrolytic nature of the complexes. The spectroscopic data and magnetic moment values along with elemental analytical data support octahedral geometries for Co(II), Ni(II), Zn(II) complexes and square planar geometry for Cu(II) complexes. ESR spectra of Cu(II) complexes exhibited g values trend as g ∥ > g ⊥ > g e. The nephelauxetic ratio (β) along with orbital reduction factors (K values) report the covalent nature of the metal-ligand bonds in complexes. Thermal analysis was also carried out to propose the composition of complexes and to determine their thermal stability. Coats-Redfern method was employed to evaluate some kinetic parameters of thermal degradation processes. In vitro antimicrobial properties of all synthesized compounds were investigated. After assessing the inhibition zones, metal complexes have been found more antimicrobial active than the Schiff base against both bacterial as well as fungal strains. Metal complexes also showed remarkable fluorescence and antioxidant properties. [ABSTRACT FROM AUTHOR]

The antibacterial activities of two previously reported copper (II) coordination complexes [Cu(HL1)Cl2] and [Cu(HL2)Cl2], and the two new complexes [Cu(HL3)Cl2] and [Cu(HL4)Cl2], where HL1 is 2-(((pyridin-2-ylmethyl)amino)methyl)phenol, HL2 is 2-((benzyl(pyridine-2-ylmethyl)amino)methyl)phenol, HL3 is 2-(((pyridin-2-ylethyl)amino)methyl)phenol and HL4 is 2-(((pyridin-2-ylmethyl)(quinolin-2-ylmethyl)-amino)methyl)phenol were investigated using agar well plate diffusion assay. The ligands were characterized using elemental analysis, IR, 1H-NMR, 13C-NMR spectroscopy and thermal analysis. The corresponding copper (II) complexes of each ligand were synthesized and characterized using elemental analysis, FT-IR and UV-Visible spectroscopy, electronic spectra and magnetic moment measurements, and thermal analysis. Additionally, a thorough investigation of the copper complexes as potent drug candidates was performed using web-based software SwissADME to predict their physicochemical and pharmacokinetics properties. All copper complexes were stable to air and moisture and showed excellent stability up to 200 °C. Electronic spectra of all copper complexes in methanol consisted of single band at 14,490–15,260 cm−1 depicting ligand field excitation (Cu (II) d–d band). Ligands were completely ineffective on gram positive bacteria; HL1 and HL3 showed moderate to high activity at concentration range of 0.2–1 mg/ml. Copper complexes were found to exhibit moderate to high activity against bacteria as compared to the ligands. SwissADME analysis of all copper (II) complexes justified their candidature as potential candidate for pharmaceutical applications. [ABSTRACT FROM AUTHOR]

Metal complexes of Co(II), Cu(II) and Ni(II) with the Schiff base ligand, 6,6ʹ-(([1,1ʹ-biphenyl]-4,4ʹ diylbis(azaneylylidene))bis(methaneylylidene))bis(2,4-dichlorophenol) (H2L) were synthesised. All synthesised compounds were identified and characterised. The conductivity measurements showed the non-electrolytic nature of all the complexes. The decomposition of all complexes ended with metal oxide. Octahedral geometries were proposed for all complexes. Photocatalytic degradation of methylene blue dye (MB) in the presence and absence of hydrogen peroxide was studied by using Co(II), Cu(II) and Ni(II) complexes as catalysts. Fluorescence studies have shown that the reported compounds can act as photoactive materials. Density functional theory was used to investigate the geometries of the ligand and its complexes. The adsorption of Co2+, Ni2+ and Cu2+ in an aqueous solution on H2L ligand under various conditions was studied. The optical properties of all complexes were studied. Antimicrobial activities of the ligand and its transition metal complexes were studied. The in-vitro cytotoxicity of ligand and its cobalt(II), nickel(II) and copper(II) complexes were evaluated towards the human Liver Carcinoma (HepG2) cell line and compared with standard cisplatin. [ABSTRACT FROM AUTHOR]

The goal of the present study is to examine pretreatment with Schiff bases and derivatives of pregabalin along with their metal (Zn and Cu) complexes on the severity of epilepsy, latency time, duration of convulsions, seizure score and survival rate in mice. To achieve the goal, a molecular docking study of analogues was carried out on a specific molecular target, such as the alpha-2δ receptor (PDB ID: 6ND9); which revealed the significant binding affinity of the analogs to their respective target. Based on the docking information, all pregabalin derivatives were synthesized and in-vivo antiepileptic effect was confirmed by applying the PTZ model that prioritized the most crucial significant points responsible for biological activity. The test compounds markedly increased the latency of the first seizure and reduced the frequency of seizures throughout the body and frequent spinning and jumps. Additionally, treatment with pregabalin derivatives in mice that received PTZ significantly reduced the duration of seizures and seizure score. However, it increased the survival rate of the mice. Since the newly synthesized compounds were more active as compared to the parent drug in some respects; therefore, the expansion of the project can be planned to explore clinical side of the drugs in the future. Docking studies of Schiff bases and derivatives of Pregabalin along with their Zn and Cu metal complexes Pretreatment with Schiff bases and derivatives of pregabalin along with their metal (Zn and Cu) PTZ Model of epilepsy Observation of different parameters including; the severity of epilepsy, latency time, duration of convulsions, seizure score and survival rate in mice Newly synthesized compounds were more active as compared to the parent drug [ABSTRACT FROM AUTHOR]

Surface functionalization of PMMA by Aminolysis reaction was utilised along with the addition of inorganic photo stabilisers (Zn(II), Ni(II), Cu(II) and Co(II)) to enhance the photostability of PMMA under exposure to UV light. The new polymers were characterised via different spectroscopic techniques. In order to assess the effectiveness of the PMMA films, Tinuvin 622, a commercial photo-stabiliser, was employed to assess the photostabilizing efficiency of our approach. The results have shown that Copper chloride was the most effective photostabilizer, followed by nickel, cobalt, and zinc chloride, in that order. [ABSTRACT FROM AUTHOR]

The ligand ((E)-((2-hydroxynaphthalen-1-yl)methylidene)amino)urea (HL) and its Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) complexes have been synthesized and characterized by conventional spectroscopic methods, elemental analysis, molar conductivity, and thermal analysis. The complexes show that the ligand disposes of as tridentate anionic (ONO) donor via deprotonated (OH)ring, (C = N)azomethine, and (C = O) functions with a ratio of metal:ligand (1:2) with Mn(II) and Co(II) ions. While, in Ni(II), Cu(II), and Zn(II) complexes, HL acts as monobasic bidentate (NO) donor ligates through deprotonated (OH)ring and (C = N)azomethine with metal:ligand of 1:2. Zn(II) complex adopts tetrahedral and other complexes adopt octahedral geometry. DFT in the material studio package validates the geometry of ligand and metal complexes by measuring bond lengths and angles, HOMO, and LUMO. The thermodynamic and kinetic parameters were estimated from TGA-DTG curves. These complexes provide better activities against human prostatic cell line PC-3 than free ligand which is further verified by molecular docking studies. 3D and 2D molecular interaction of ligand, HL to inhibitory activity to the 2Q7I protein. Highlights: Synthesis of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) complexes of ligand (HL). Elemental analysis, molar conductivity, spectral methods (IR, UV-Vis., ESR, mass, and 1H NMR). The kinetic thermodynamic parameters (ΔE, ΔH, ΔS, and ΔG) are estimated from the TGA-DTG curves. Complexes provide better activities against human prostatic cell line PC-3 than the free ligand. Molecular docking of ligand and complexes with the receptor of prostate cancer (H874Y) hormone. [ABSTRACT FROM AUTHOR]

A series of octahedral Zn(II), Cu(II), Ni(II), and Co(II) complexes have been synthesized with ONO donor Schiff base ligand N'-(6-chloro-2-oxoindolin-3-ylidene)nicotinohydrazide (3) derived from the reaction of 6-chloro isatin (1) and isoniazid (2). The chemical structures of the compounds were elucidated by spectral and physicochemical techniques. The spectral data reveal the octahedral geometry for all the metal (II) complexes. The compounds were screened for their antibacterial and antifungal activity; all the metal (II) complexes exhibited enhanced activity. The Cu(II) and Co(II) complexes displayed equipotent anti-TB activity when evaluated with standard Ciprofloxacin. Furthermore, the Ni(II) and Co(II) complexes showed excellent antioxidant activity compared to the standard drug. Density Functional Theory (DFT) estimations for ligand (3) at the DFT/B3LYP level via 6-31 G++ (d, p) replicate the structure and geometry. Finally, HOMO and LUMO analysis was used for the charge transfer interface of the structure. The Cu(II), Ni(II), and Co(II) complexes exhibited good docking properties in molecular docking studies against Cytochrome c Peroxidase (2 × 08). [ABSTRACT FROM AUTHOR]

A highly sensitive, selective and accurate method has been developed to determine ultra trace amounts of copper(II) by solid-phase extraction (SPE). The following parameters such as pH, concentration of the reagent, Triton X-100, reversed-phase Amberlite IR-120, equilibrating temperature and centrifuging time were evaluated to enhance the sensitivity and extraction efficiency of the proposed method. The method has been based on copper(II) and 4-((furan-2-ylmethylene) amino)-5-methyl-4 H-1,2,4-triazole-3-thiol (FAMT) reaction, followed by solid-phase extraction (SPE) of Cu(II)-FAMT with a reversed-phase Amberlite IR-120. This was performed by using borate buffer solution of pH 7.6 in the presence of Triton X-100 medium. FAMT reacts with copper(II) to form a deep green complex with molar ratio of (2: 1) (FAMT: copper). An enrichment and improvement factor of 200 and 540, respectively, were obtained by elution of the complex from the resin with a minimal amount of dimethylsulfoxide (0.5 mL). The molar absorptivity of the complex was 6.49 × 106 L mol−1 cm−1 at 499 nm. Beer's law was obeyed in the range 5.0–190 ng mL−1 of the measured solution. After optimising the instrumental and experimental parameters, the maximum values for quantification and detections limits of 100 mL sample system were 5.40 and 1.64 ng mL−1. The suggested method has been successfully applied for determination of copper ions in various environmental (water, vegetables, food, and biological) samples. [ABSTRACT FROM AUTHOR]

Centrosymmetric homopolynuclear Cu(II) and Co(II) chelated complexes, [Cu2(L)(H2O)2] (1) and [Co4(L)(μ-OAc)2(CH3OH)4(OAC)2]⋅2CH2Cl2 (2), were synthesized using a new symmetrical methoxy-disubstituted bis(salamo)-type ligand, H4L, with Cu(II) and Co(II) salts in organic solvents. Complexes 1 and 2 were structurally characterized by single-crystal X-ray crystallography. The results indicated that 1 is a five-coordinate dinuclear structure containing Cu(II) and 2 is a tetranuclear Co(II) complex with two distinct six-coordinate environments. Furthermore, 1 and 2 pack into three-dimensional and two-dimensional extended networks, respectively. The UV–Vis spectra, IR spectra, and Hirshfeld surface analyses of the complexes were carried out to further characterize the coordination between H4L and the metal(II) ions. Fluorescence methods were used to interrogate the coordination, where changes in emission with varied amounts of ligand supported solution-phase coordination ratios of H4L with Cu(II) ion of 1:2 and with Co(II) ion of 1:4, respectively. [ABSTRACT FROM AUTHOR]

The properties of films prepared from polystyrene (PS), poly(methyl methacrylate) (PMMA), and polystyrene (PS)/poly(methyl methacrylate) (PMMA) blends and composite films prepared with metal ion-centered complexes were compared. New complexes of Cr(III), Co(II), Ni(II), and Cu(II) prepared according to the template were synthesized from ligand L (4-hydroxy-N-[2-[(4-hydroxybenzoyl)amino]ethyl]benzamide) prepared by condensation of 4-hydroxybenzoic acid and ethylenediamine. Structural analysis of ligands and complexes were determined by LC-MS, 1H-NMR, FTIR, UV-Vis, and XRD. The conductivities and magnetic susceptibility of novel complexes were measured. Morphological properties of the transparent films by SEM and AFM, their thermal stabilities by TGA, and their optical properties by refractometry were characterized. Original composite films of PS, PMMA, and PS/PMMA blend modified with novel complexes were obtained as thermally stable, transparent, and foldable composite films with permanent colors. [ABSTRACT FROM AUTHOR]

The reactions of copper chloride and 4′-(4′-substituted-phenyl)-2,2′:6′,2′′-terpyridine ligands bearing nitro (L1), methyl (L2), phenyl (L3), tolyl (L4) and carboxyl (L5) gave five copper compounds (1–5) which have mononuclear structures with their Cu(II) ions five-coordinate in the irregular square pyramidal geometries. Their in vitro biological properties were evaluated by CCK-8 assay, which show remarkable proliferation inhibitive properties on the cancer cell lines including A549, Eca-109, and Bel-7402, and two human normal cell lines (HL-7702 and HLF). The values of IC50 indicate better anticancer activities of these compounds than that of cisplatin. Compound 2 with methyl group exhibits the best anticancer activity, with IC50 value < 2.5 µM on all the tested cancer cells. The interactions of the compounds with DNA were evaluated using UV–Vis absorption titrations, circular dichroism spectroscopy, and DNA viscosity. The complexes show significant insertion binding with DNA sequences and strong intercalator binding mode with DNA sequences. Compounds 1–5 interact with the functional groups of DNA through π···π stacking, van der Waals interactions, hydrophobic interactions, and hydrogen bonds as determined by molecular docking. In addition, strong binding interactions between the five copper(II) complexes and bovine serum albumin (BSA) were studied by fluorescence titration and circular dichroism spectroscopy. [ABSTRACT FROM AUTHOR]

Template condensation between pentane-1,5-dial and triethylenetetramine in the presence of divalent metal salts in methanolic solution resulted in mononuclear 15-membered tetraazamacrocyclic Schiff base metal complexes, [M(C11H22N4)X2], where M = Co(II), Ni(II) and Cu(II), X = Cl− and C11H22N4 is the tetradentate macrocyclic ligand. The bonding and overall geometry of the complexes are inferred through elemental analysis, FT-IR, UV–vis, 1H/13C NMR, ESI-mass, molar conductance, magnetic susceptibility and TG measurements. On the basis of the absorption bands in UV–vis spectra and magnetic moment analyses, a six-coordinate octahedral geometry is proposed for all the metal complexes. The formulation of the metal chelates is compatible with the thermal decomposition profiles. Photocatalytic efficiency of the macrocyclic Ni(II) complex was studied using solar water-splitting. The in vitro antimicrobial activity of metal complexes has been tested against certain bacterial and fungal species. The scavenging ability of DPPH free radicals was used to test the antioxidant activity of the complexes. In addition, MTT assay was used to assess the cytotoxicity of Cu(II) chloro complex against L929 mouse fibroblast cell lines. [ABSTRACT FROM AUTHOR]

Two new one-dimensional (1-D) end-to-end azido and thiocyanato bridged Cu(II) coordination polymers, [Cu(L)(µ-1,3-N3)]n(ClO4)n (1) and [Cu(L)(µ-1,3-NCS)]n(ClO4)n (2) with a morpholine-based tridentate N,N,N-donor Schiff base ligand (1-methyl-1H-imidazol-2-yl)-N-[2-(morpholin-4-yl)ethyl]methanimine, L) have been synthesized. Compounds 1 and 2 have been characterized by elemental analyses and spectroscopic techniques. The X-ray single crystal structures of 1 and 2 show the formation of regular zigzag chains with µ-1,3-azido and µ-1,3-thiocyanate bridges, respectively. Variable temperature (2–300 K) magnetic studies indicate that 1 shows a ferromagnetic intrachain exchange interaction with g = 2.135(2) and J = 2.13(2) cm−1, while in 2 this interaction is antiferromagnetic with g = 2.1412(3) and J = –0.277(2) cm−1. X-band EPR spectra of 1 and 2 in frozen (143 K) DMF solution corroborate our magnetic studies. [ABSTRACT FROM AUTHOR]

As previously reported, we have synthesized an azo azomethine ligand 4-((E)-(2,5 dichloro phenyl) diazenyl)−2-((E)-((4-hydroxyphenyl) imine) methyl) phenol (L). The synthesized ligand has been used to prepare copper(II), nickel(II), and cobalt(II) metal complexes and characterized using various analysis techniques. To identify complexes, methods, such as elemental analyses, electrical conductivity, IR spectroscopy, mass spectrometry, magnetic moment, vibrating sample magnetometry (VSM), 1HNMR, UV–Vis, and thermal analysis were utilized, and a mononuclear structure was proposed for all compounds and all the complexes are non-electrolytes in nature. The chelation of the ligands to the metal ions occurs through phenolic oxygen and nitrogen atoms of the azomethine group of the ligands. According to various analytical and spectral data, a square planar structure is proposed for copper and nickel metal complexes and a quadrilateral structure is proposed for cobalt complexes. The antibacterial properties of ligands and complexes of copper(II), nickel(II), and cobalt(II) were investigated in vitro on standard bacteria as well as on bacteria isolated from clinical specimens (urine). The results revealed that the ligand and its metal complexes had a very high antibacterial activity against Staphylococcus aureus, but were ineffective against other studied bacteria. The synergistic effect of the compounds with the three antibiotics (vancomycin (V), methicillin (M), and trimethoprim (T)) was also investigated, along with the cytotoxicity of its ligand and copper complex in HFF cell line. At a concentration of 3.90 μl of these compounds, cell viability was significant. The structure of ligand and complexes was optimized by DFT calculations. Computational methods were performed for deeper understanding of the interaction between ligands and metal by EDA calculations. This result confirmed that the bonding between ligands to metal was mainly covalent. The complexes investigated are reported for the first time. The search for new antimicrobial agents against Staphylococcus aureus is an urgent medical need. Therefore, sensitive and selective diagnosis of this pathogenic bacterium is of great importance, which has been obtained in this study. The compounds synthesized from among the nine gram-negative and gram-positive bacteria are only sensitive to Staphylococcus aureus bacteria. [ABSTRACT FROM AUTHOR]

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

By single-crystal X-ray diffraction (XRD) analysis, five complexes, catena-[(µ-2,2-bis(4-carboxyphenyl)hexafluoropropane)-(2-(pyidin-2-yl)-1,3-benzothiazole)-aqua-zinc(II)] (1), catena-[(µ-2,2-bis(4-carboxyphenyl)hexafluoropropane)-(2-(pyidin-2-yl)1,3-benzothiazole)-aqua-cadmium(II)] (2), catena-[hepta(µ-2,2-bis(4carboxyphenyl)hexafluoropropane)-diaqua-bis(2-(pyidin-2-yl)-1,3-benzothiazole)-tri-manganes(II)] (3), catena-[(µ-benzene-1,2,4,5-tetracarboxylato)-(2-(pyidin-2-yl)-1,3benzothiazole)copper(II)] (4) and catena-[(µ-3-nitrobenzene-1,2-dicarboxylato)-(2-(pyidin-2-yl)1,3-benzothiazole)-aqua-zinc(II)] (5), were characterized in this research. In these five complexes, H2hfipbb = 2,2-bis(4-carboxyphenyl)hexafluoropropane, H4btec = 1,2,4,5-benzenetetracarboxylic acid, H2NPTA = 3-nitrophthalic acid and bpt = 2-(pyridin-2-yl)benzo[d]thiazole). Complexes 1 and 2 occur in the monoclinic system with space group C2/c, 4 and 5 occur in the monoclinic system with space group P21/c, and 3 occurs in the triclinic system with space group P-1. The interaction between CT-DNA (calf thymus DNA) and those complexes was examined using UV spectroscopic analysis, fluorescent spectroscopic analysis, circular dichroism spectroscopy (CD) and viscosity analysis. This research reveals that those complexes have strong ability to interact with DNA, and they all bind to DNA in an intercalation mode, thus affecting the structure of DNA. This binding mode can arise from the interaction between the benzothiazole metal complexes and DNA. Hence, we hope to provide some scientific research bases for studying benzothiazole complexes and designing new thiazole anticancer drugs. [ABSTRACT FROM AUTHOR]

Three new copper(II) and cadmium(II) complexes, [Cu(L1)2] (1), [CuL2(N3)] (2), and [Cd(L3)2] (3), where L1 = 2-bromo-4-chloro-6-cyclohexylaminomethylphenolate, L2 = 2-bromo-4-chloro-6-[(2-morpholin-4-ylethylimino)methyl]phenolate, and L3 = 2-bromo-4-chloro-6-[(3-morpholin-4-ylpropylimino)methyl]phenolate, have been prepared and structurally characterized by X-ray crystallography. The Cu atom in complex 1 is in tetrahedrally distorted square planar geometry. The Cu atom in complex 2 is in square planar geometry. The Cd atom in complex 3 is in octahedral geometry. The complexes exhibited effective activities against B. subtilis, S. aureus, and E. coli. [ABSTRACT FROM AUTHOR]

A centipede like thiocyanate-bridged multi-nuclear copper(I/II) complex, [Cu2L(CH3OH)(NCS)3]n, derived from 2-(((2-(dimethylamino)ethyl)imino)methyl)-5-fluorophenol (HL), was prepared and characterized by elemental analysis, IR and UV–vis spectra, as well as single crystal X-ray diffraction. The Cu1 ion in the +2 oxidation state is coordinated by the tridentate Schiff base ligand in a square pyramidal geometry, with the other two sites occupied by one N atom of the thiocyanate ligand and one methanol O atom. The Cu2 ion in the +1 oxidation state is coordinated by one N and three S atoms from four thiocyanate ligands, forming a tetrahedral geometry. The CuI ions are linked by thiocyanate ligands to form a one-dimensional chain with [CuI2(μ1,3,3-NCS)2] as the repeat unit. The [CuIIL(CH3OH)] moieties are linked to the chain through thiocyanate ligands. The complex has remarkable inhibitory activity on Jack bean urease with an IC50 value of 1.3 μmol L–1. [ABSTRACT FROM AUTHOR]

The title compound ([CuClL(H2O)]·2H2O) were synthesized. The copper(II) complex in square planar geometry were identified by using elemental analysis, magnetic susceptibility, mass spectra, FT-IR, UV-Vis. and ESR techniques. DFT calculations at the UB3LYP/LANL2DZ level of theory were conducted to obtain vibrational and electronic properties of the copper(II) complex. Vibrational assignments of the observed infrared spectra of title compound were carried out based on the calculated potential energy distributions (PEDs). The sensitive measurement results indicated that the observed values were reasonable. The energy values were determined to describe electronic properties of the title molecules. Furthermore, NBO analysis was performed to analyze the hyper-conjugative stability of the molecule, molecular orbital interaction and charge delocalization. [ABSTRACT FROM AUTHOR]

A complex containing two discrete molecules, [Cu2(bpy)2(4-Ab)2(NO3)(H2O)] and [Cu2(bpy)2(4-Ab)2(H2O)2] and the lattice including three NO3 anions, one 4-Ab, and three H2O molecules (bpy = 2,2′-bipyridine, 4-Ab = 4-aminobenzoate), was prepared and structurally determined using elemental analyses, IR, EPR, UV-visible, and single-crystal X-ray crystallography. X-ray single-crystal structural studies indicated that the [Cu2(bpy)2(4-Ab)2] unit was present in both the crystallographic units. The complex crystallized in an orthorhombic crystal system with space group Pna21, a = 35.004(3) Å, b = 18.4134(16) Å and c = 12.8659(12) Å. In both crystallographic units, the geometry of the Cu(II) ions is distorted square-pyramidal, where both nitrogen atoms from one bpy and two oxygen atoms from two different p-aminobenzoate ions constitute the square plane and the apical positions are occupied by solvent or nitrate oxygen atoms. The geometry optimization of both units of the binuclear complex was carried out by taking the coordinates of the respective X-ray structures using DFT. The binding studies of the copper(II) complex with calf thymus DNA (CT-DNA) were explored by UV-Vis absorption, fluorescence spectroscopic, and cyclic voltammetric techniques. Also, the cleavage of pBR322 DNA with the binuclear copper(II) complex was studied using the gel electrophoresis method. [ABSTRACT FROM AUTHOR]

Three newly synthesized copper(II) complexes with the general formula [CuL], where L is the dianionic form of N,N′-bis(3,5-difluorosalicylidene)ethane-1,2-diamine (H2L1) for 1, N,N′-bis(3,5-difluorosalicylidene)propane-1,3-diamine (H2L2) for 2, and N,N′-bis(3,5-difluorosalicylidene)-2-hydroxy-1,3-propanediamine (H2L3) for 3, have been obtained and structurally characterized by spectroscopic method and single-crystal X-ray determination. The Cu atoms in the complexes are in square planar coordination, with the two imino N and two phenolate O atoms of the Schiff base ligands. The in vitro antimicrobial activities of the compounds indicate that they are interesting antibacterial agents. [ABSTRACT FROM AUTHOR]

In this paper, a novel air/moisture stable copper(II)-Schiff base complex supported on multi-walled carbon nanotubes (APTMS@MWCNTs/Schiff base/Cu) has been prepared and characterized by Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDAX), and scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Its catalytic activity has been examined in the synthesis of some important dihydro-spiro[cycloalkane-1,4′-quinoline]-2′,5′-diones via a one-pot, one-step four-component reaction of various cyclic ketones, dimedone, Meldrum's acid, and amines/ammonia in refluxing ethanol. A wide range of desired products has been obtained through creating new C–C and C–N bonds in good yields. The recovery and reusability of the nanocatalyst has also been checked through three runs without activity loss. [ABSTRACT FROM AUTHOR]

In this work, three isomeric Schiff's bases: salicylidene-2-nitroaniline N2HB2NA, salicylidene-3-nitroaniline N2HB3NA, and salicylidene-4-nitroaniline N2HB4NA, were synthesized and their effect on the liquid-liquid extraction of copper (II) was studied. During the extraction of metal ions from sulfate media in chloroform at 25°C, it has been shown that substitution of nitro group to the ortho, méta and, para position of the aniline ring in salicylideneaniline led to a large increase in the extraction of copper ions. It was concluded that the extracted species are CuL2 (L denote N2HB2NA, N2HB3NA, or N2HB4NA). The results revealed that the best extraction efficiencies for Cu2+ were according to the following order: N2HB2NA > N2HB3NA> N2HB4NA. [ABSTRACT FROM AUTHOR]

Three new bis-azomethine derivatives were synthesized in a good yield, along with their copper(II) complexes and confirmed by IR, 13C-NMR, 1H-NMR, MS, ESR, powder XRD and UV-vis spectroscopy. The spectral studies indicated that the ligands in all complexes act as dibasic tetradentate, coordinated through two azomethine nitrogen and two deprotonated phenolic oxygen atoms. Square planar geometries were assigned for Cu(II) complexes in monomeric structures. Also, quantum chemical calculations using DFT were conducted to elucidate the effect of quantum chemical parameters on the molecular and electronic structures of the molecules under consideration, and then confirming their electrochemical behavior and biological effectiveness. There were good correlations between practical and theoretical studies. The redox pathway of bis-azomethine derivatives and their Cu(II) complexes was elucidated and confirmed based on experimental and theoretical calculations. In vitro antimicrobial effectiveness of the synthesized three ligands and their Cu(II) complexes exhibited varying degrees of inhibitory effect on the growth of the test pathogenic microorganisms, confirming that antimicrobial efficiency is dependent on the molecular structure of the prepared compounds and their liposolubility. The MIC was also determined for the compound H2Lc which exhibited the highest antimicrobial activity against each of Pseudomonas aeruginosa (G-) and Candida albicans. [ABSTRACT FROM AUTHOR]

An end-on azido-bridged dinuclear copper(II) complex, [Cu2L2(μ1,1-N3)2], where L is the deprotonated form of N-(2-hydroxy-4-methoxybenzylidene)picolinamide (HL), has been prepared by the reaction of 5-methoxy-2-[(pyridin-2-ylmethylimino)methyl]phenol (HL′) with copper bromide and sodium azide in methanol. The structure of the complex was characterized by elemental analysis, IR and UV–vis spectra, and single crystal X-ray diffraction. The complex possesses crystallographic inversion symmetry, with the two Cu ions (3.36 Å) bridged by two end-on azido bridges. Each Cu ion is in a square pyramidal coordination. The original ligand HL′ was unexpectedly oxidized to HL under mild conditions during preparation of the complex. The complex has excellent urease inhibitory activity. [ABSTRACT FROM AUTHOR]

A 2-D homometallic mixed-valence copper coordination polymer, catena-poly[[tetrakis(μ-cyanido)-{(1-(N-acetopyridinine)-2-aminoethane)}-tri-copper] methanol monosolvate], {[Cu3(L)(CN)4]·CH3OH}n (1) [L = 1-(N-acetopyridinine)-2-aminoethane], has been isolated using a one-pot reaction of the building components and was characterized. The crystal structure consists of [CuIIL]2+ units and copper(I) ions bridged by μ-CN anions. The copper(II) center of the CuN5 chromophore displays a square pyramidal coordination geometry provided by three N atoms of the tridentate Schiff base and two N atoms of μ-NC ions, while the copper(I) centers adopt a trigonal-planar geometry. Three copper centers are interconnected through μ-CN/μ-NC via {-Cu1(L)(μ-NC)2Cu2(μ-CN)Cu3(μ-NC)-} units to form 2-D polymeric ribbons parallel to the b-axis. These 2-D polymeric ribbons in the crystalline state are further stabilized through π···π stacking interactions. Hirshfeld surface analysis was performed to gain additional insight into the interactions responsible for the packing of 1. Variable-temperature magnetic susceptibility studies showed a weak ferromagnetic interaction among the copper centers in 1 through cyanide bridges with J = 1.28 cm−1. [ABSTRACT FROM AUTHOR]

A dimeric copper(II) complex, bis{(2-[1-(aminoethylimino)ethyl]-phenoxo}-di-μ1,1-azido-dicopper(II), [Cu2(L)2(μ2-1,1-N3)2] (1) [L = 2-[1-(aminoethylimino)ethyl]-phenoxo ion], has been isolated using a self-assembly reaction using a 1:1:1 molar ratio of Cu(NO3)2·3H2O, HL and NaN3 in methanol at room temperature and characterized through X-ray diffraction analysis and spectroscopic studies. X-ray structural analysis reveals that 1 consists of two distinct dinuclear molecular units, where each copper(II) center in the individual dinuclear unit adopts a distorted square pyramidal geometry with a CuN4O chromophore ligated through a tridentate (NNO) Schiff base and two N atoms of two different bridging azides in µ1,1-mode. Two Cu(II) centers are linked through double µ2-1,1-N3 bridges to form the dinuclear unit [Cu2(L)2(μ2-1,1-N3)2]. In the crystalline state, the dinuclear units in 1 are associated through weak intermolecular N-H⋯O hydrogen bonds to afford a 2-D sheet structure viewed along the crystallographic a-axis. The small magnitude of the antiferromagnetic interaction (J = –0.45 cm−1) is a result of the long Cu···Cu separation (3.205(2) Å). The catalytic efficacy of 1 was studied in a series of solvents for the epoxidation of alkenes using tert-butyl-hydroperoxide (TBHP) as an efficient oxidant under mild conditions. [ABSTRACT FROM AUTHOR]

Two copper(II) complexes, [Cu2(L1)2]·2H2O (1) and [Cu3(L1)2(NCS)2] (2), and two nickel(II) complexes, [NiL2(NCS)] (3) and [Ni(L2)2(NCS)]·CH3OH (4), were prepared from the fluorine substituted Schiff bases N,N'-bis(4-fluorosalicylidene)-1,2-diaminopropane (H2L1) and 4-fluoro-2-[(2-isopropylaminoethylimino)methyl]phenol (HL2), respectively. The compounds were characterized by physico-chemical methods. Structures of the complexes were further confirmed by single crystal X-ray diffraction. The Cu ions in 1 are square pyramidal, and in 2 are square planar and octahedral. The Ni ion in 3 is square planar, and in 4 is octahedral. All the complexes have effective Jack bean urease inhibitory activities. Complex 1 has the most effective activity, with an IC50 value of 2.1 ± 1.3 μmol L−1. [ABSTRACT FROM AUTHOR]

A new heteronuclear complex [LCuCo(NO3)2] (1) (H2L = N,N'-ethylenebis [3-methoxysalicylaldimine]) was synthesized and structurally characterized. The complex consists of a dimer skeleton which composed of a slightly distorted square-planar copper and pentacoordinated cobalt ions. The magnetic properties reveal the presence of antiferromagnetic interactions between the metal centers linked by double phenoxo-bridging. [ABSTRACT FROM AUTHOR]

A new dinuclear copper(II) Schiff base complex, [Cu2L2(H2O)2(µ-ClO4)]ClO4, was synthesized and characterized by single crystal X-ray crystallography, FT-IR and UV-Vis spectroscopy, and elemental analysis. In this complex, L−1 is the deprotonated form of N-5-bromosalicylidene-1,3-propanediamine. Single crystals of the complex were crystallized in the monoclinic crystal system and P21/n space group. The geometry around each metal center is distorted octahedral in which the monoanionic Schiff base ligand has occupied three apices of the octahedron and the other three apices are occupied by a water molecule, an oxygen atom of the µ-perchlorato anion, and a phenoxo type oxygen atom from the other Schiff base ligand. Antibacterial properties of the synthesized complex have been investigated against human pathogenic bacteria, such as Escherichia coli, Klebsiella pneumonia, Salmonella (sp) and Proteus (sp), and Staphylococcus aureus. The complex showed moderate antibacterial activity against both Gram-type bacteria with the highest activity against K. pneumonia and E. coli. [ABSTRACT FROM AUTHOR]

Azo Schiff base ligand 2-hydroxy-3-methoxy-5-(tolyldiazenyl)benzaldehyde oxime (HL1) and 2-hydroxy-3-methoxy-5-(methoxyphenyl)benzaldehyde oxime (HL2) were prepared along with their transition metal complexes of Ni(II), Cu(II), and Zn(II). Ligands and their metal complexes were characterized by several analysis techniques. In- vitro antibacterial, antioxidant and anti-inflammatory activities of synthesized ligands and their metal complexes have been studied. Biological study showed that amongst all the synthesized compounds, Cu(II) complexes possessed excellent antibacterial activity than standard antibiotic Chloramphenicol. Ligands (HL1) and (HL2) showed excellent antioxidant as well as anti-inflammatory activity. Both the ligands were tested for their protective effect of free radicals against plasmid DNA and it was found that both the ligands showed good DNA nicking activity. [ABSTRACT FROM AUTHOR]

Pyridine-2-carboxaldehyde-semicarbazone (PCS) complex [(H2PCS).Cl]+[Fe(II)(PCS)Cl3]–.[Fe(III)(PCS)Cl3] · (HPCS) · (Cl) (1) and 2,3-diacetylhydrazoneoxime (DAHO) complex [Cu2(μ-Cl)2(DAHO)2Cl2] (2) have been synthesized and characterized by different spectroscopic techniques. Structures were confirmed by single crystal X-ray crystallographic technique. Complex 1 crystallizes as Fe(II)/Fe(III) coordination complex in triclinic crystal system. EPR signals of 1 at g = 4.2 and g = 1.8 show transitions within mS = ±3/2 and mS = ±1/2 Kramers' doublets of high spin (S = 5/2) distorted octahedral Fe(III) complex. Complex 2 crystallizes in triclinic system as square pyramidal chloro-bridged dinuclear copper(II) complex. The complexes were found to be groove binding to calf-thymus DNA. [ABSTRACT FROM AUTHOR]

A novel red copper(II) compound, bis(μ-bromo)bis(2-(benzothiazol-2-yl-hydrazono)-1,2-diphenyl-ethanone)-dicopper(II) (1), has been fostered by equimolar reaction of a Schiff-base ligand, 2-(benzothiazol-2-yl-hydrazono)-1,2-diphenyl-ethanone (LH), with copper(II) bromide in satisfactory yield. 1 has thoroughly been characterized by C, H and N elemental analyses, FT-IR and UV-vis (both in solid state and in solution) spectroscopies, and room-temperature magnetic susceptibility and conductivity measurements. Dimeric 1 bears symmetric rare bromo-bridges in its crystal structure. 1 retains its solid-state identity even in a protic solvent like methanol. 1 in methanol displays two-step one-electron redox response. Theoretical calculations based on DFT were executed to probe the electronic structure of 1 and to augment its color. DNA- and RNA-binding aspects of both LH and 1 have been explored. Thermodynamic binding parameters have been determined. LH is a major-groove binder to DNA, while 1 manifests itself as a minor-groove binder. This binding has been corroborated through molecular docking. Nucleic acid binding aspect of such type of rare bromo-bridged red copper(II) dimer is unprecedented. [ABSTRACT FROM AUTHOR]

A novel Schiff base designated as 5-[(3-methylthiophene-2-yl-methyleneamino)]-2-mercaptobenzimidazole was synthesized and characterized. A polyvinyl chloride-membrane potentiometric copper(II)-selective sensor was prepared by using the synthesized 5-[(3-methylthiophene-2-yl-methyleneamino)]-2-mercaptobenzimidazole compound. The prepared polyvinyl chloride-membrane copper(II)-selective sensor exhibited very good selectivity and sensitive potentiometric response towards copper(II) ions compared to a wide variety of other cations. The sensor had a fast response time of <5 s, and showed a linear Nerstian behavior to copper(II) ions over a wide concentration range from 1.0 × 10−5 to 1.0 × 10−1 mol L−1 with a slope of 29.2 ± 0.7 and correlation coefficient of 0.9998. The prepared polyvinyl chloride-membrane copper(II)-selective sensor was used for 14 weeks without any significant change in its potentiometric response. The potentiometric response of the developed sensor was highly repeatable. Additionally, the developed sensor was used as an indicator electrode for the potentiometric titration of copper(II) ion with ethylenediaminetetraacetic acid. The sensor was also successfully applied to the direct determination of copper(II) ions in tap water, river water, and dam water samples. [ABSTRACT FROM AUTHOR]

Three new Cu(II) Schiff base complexes with bidentate N-donor heterocyclic co-ligands, 2,2'-bipyridine (1), 1,10-phenanthroline (2), and 2,9-dimethyl-1,10-phenanthroline (3), were synthesized and characterized by FT-IR and UV-vis spectroscopy. Molecular structures of [C20H21CuN4O](ClO4) (1) and [C24H25CuN4O](ClO4) (3) were characterized by single-crystal X-ray crystallography. The Schiff base ligand is an N2O-type ligand, which is the mono-condensed form of the reaction between 1,3-propanediamine and salicylaldehyde. The antibacterial activities of these complexes were investigated against one gram positive and four gram negative bacteria. Considerable antibacterial activity was obtained against both gram type bacteria. Complexes 2 and 3 with 1,10-phenanthroline and 2,9-dimethyl-1,10-phenanthroline, respectively, showed better antibacterial activity compared to 1 which has the 2,2'-bipyridine co-ligand. [ABSTRACT FROM AUTHOR]

In this work, the 2-(2-(pyridin-2-yl)oxazolidin-3-yl)ethanol (AEPC) ligand was prepared under solvent free conditions using ultrasonic irradiation, before reaction with a Cu(NO3)2/KSCN mixture, CuCl2 and CuI, the products of which were characterized by elemental analysis, UV-Vis, FT-IR spectroscopy and single-crystal X-ray diffraction. The X-ray analyses results revealed that AEPC, after reactions with the three copper(I/II) halides, gave structures ([Cu(DEA)Cl2] (2), DEA = diethanolamine, [Cu(BHEG)2] (3), BHEG = bis(2-hydroxyethyl)glycinato); however, it retains its structure on treatment with Cu(NO3)2/KSCN mixture ([Cu(AEPC)(NCS)2] (1)). The geometrical parameters for the complexes were compared with the Cambridge Structural Database (CSD) and coordination modes for thiocyanate ion were extracted. In the crystal structure of 1, the copper ion has a distorted square-pyramidal geometry and a CuNpyN2NCSNtertOalc environment in which the AEPC acts as NN'O-donor in a facial coordination mode. In the crystal structure of 2, the copper ion has a Cu(Nsec)(Oalc)2Cl2 environment and distorted square-pyramidal geometry in which the DEA ligand is coordinated as a mer-NO2-donor. The copper ion in 3 has a CuN2O4 environment and distorted octahedral geometry. The ability of these compounds to interact with the nine biomacromolecules (BRAF kinase, CatB, DNA gyrase, HDAC7, rHA, RNR, TrxR, TS and Top II) was investigated by Docking calculations and compared with that of doxorubicin. The thermodynamic stability of 1 and its isomer and also charge distribution patterns were studied by DFT and NBO analysis, respectively. [ABSTRACT FROM AUTHOR]

Urease catalyzes the decomposition of urea into ammonia, which has harmful effects on both human health and fertile soil. Aiming at exploring novel urease inhibitors, a series of hydrazone compounds and their CoIII, CuII, NiII, and ZnII complexes were prepared from 4-methoxy-N'-(pyridin-2-ylmethylene)benzohydrazide (HL). They are [CoClL(NCS)] (1), [CoL2]·Cl·CH3OH·H2O (2), [CuL(NCNCN)]n·nCH3OH (3), [NiL(HL)]·ClO4·CH3OH (4) and [ZnClL(OH2)]·CH3OH (5). The compounds were characterized by physico-chemical methods. Structures of the complexes were further confirmed by single crystal X-ray diffraction. The metal ions in 1, 3, and 5 display square pyramidal coordination and 2 and 4 display octahedral coordination. The inhibitory effects of the compounds on Jack bean urease were evaluated. The results showed that 3 has effective urease inhibitory activity, with IC50 value of (7.3 ± 1.0) μmol L−1. [ABSTRACT FROM AUTHOR]

We, the Editors and Publisher of the journal Inorganic and Nano-Metal Chemistry, have retracted the following article: Dong-Cheng Hu, Li-Wei Chen, Yun-Xia Yang & Jia-Cheng Liu. Syntheses, structures and antioxidant activities of two new Cu(II) complexes with a benzimidazole schiff base ligand, Inorganic and Nano-Metal Chemistry. 2018. DOI: Since publication, significant concerns have been raised about the integrity of the data and reported results in the article. When approached for an explanation, the authors did not provide their original data or any necessary supporting information. As verifying the validity of published work is core to the integrity of the scholarly record, we are therefore retracting the article. The corresponding author listed in this publication has been informed. We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as 'Retracted'. [ABSTRACT FROM AUTHOR]

A novel chlorido-coordinated and phenolato-bridged trinuclear copper(II) complex, [Cu3L2Cl2], derived from the Schiff base N,N′-bis(5-bromosalicylidene)propane-1,3-diamine (H2L), was prepared and characterized by elemental analysis, IR spectra, and single crystal X-ray analysis. The crystal of the complex crystalizes in the orthorhombic space group Cmca, with a = 22.8644(15), b = 10.6187(7), c = 15.7887(10) Å, V = 3833.3(4) Å3, Z = 4. The complex possesses crytallographic inversion center symmetry, with the inversion center located at the inner Cu atom. The outer two Cu atoms are in square pyramidal coordination, and the inner Cu atom is in square planar coordination. The antibacterial activity of the complex was studied, which indicated that it is more active against E. coli. [ABSTRACT FROM AUTHOR]