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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]

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 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]

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]

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]

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]

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]

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 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 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]

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]

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]

Four novel Schiff base ligands and their copper(II) complexes, [Cu(L1)2] (1), [Cu(L2)2] (2), [Cu(L3)2] (3), and [Cu(L4)2] (4), were synthesized and characterized by elemental analyses, FT-IR, and UV–Vis spectroscopy. The ligands were synthesized from the condensation of 2-methoxyethylamine with various salicylaldehyde derivatives (x-salicylaldehyde for HLn, x = H (n = 1), 5-Br (n = 2), 3-OMe (n = 3), and 4-OMe (n = 4)). The molecular structures of 1, 2, and 3 were determined by the single crystal X-ray diffraction technique. The redox behavior studies of the complexes in acetonitrile display the electronic effects of the groups on the redox potential. The antioxidant activity of the Schiff base ligands and their Cu(II) complexes was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method and FRAP assay. Furthermore, the in vitro anticancer activity of compounds was screened, including MTT and migration assays against gastric cancer cell line (MKN-45). The results show that all ligands and complexes have antioxidant and anticancer activity in a concentration-dependent way. [ABSTRACT FROM AUTHOR]

The multidentate Schiff-base ligand N′-(1-(pyrazin-2-yl)ethylidene)isonicotinohydrazide (HL) has been prepared. Reaction with zinc, copper, and silver nitrate afford three complexes, [Zn(HL′)2](NO3)2·3H2O (1), {[Cu2(L)2(NO3)(H2O)2]·NO3}n(2) and {[Ag2(L)2]·3H2O}n(3). These complexes have been characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. In1,HLis a neutral tridentate ligand, whereas in2and3,HLis a deprotonated tetradentate ligand. The hydrogen bonding interactions between NO3−and the host framework result in various supramolecular polymeric structures: a 2-D layer for1and 3-D network for2and3. The antibacterial activities of these complexes have been investigated and the results indicate that3showed good antibacterial activities. [ABSTRACT FROM PUBLISHER]

Using the 1 : 2 condensate of benzil and 2-hydrazinopyridine as the ligand LH2(H: dissociable NH proton), the red complex Cu(LH2)(ClO4)2(1) was synthesized. The ligand also afforded the orange [Zn(LH2)(OH2)2](ClO4)2(2). The X-ray crystal structures of the ligand,1and2have been determined. The metals in1and2have octahedral N4O2environments.1is paramagnetic withμeffof one unpaired electron (1.63 μBand displays an axial EPR spectrum in the solid state with  = 2.07, characteristic of a (dx2−y2)1ground state (g|| > g⊥;A|| = 16 mT). In cyclic voltammetry,1displays a two-electron oxidation around 0.9 VversusNHE. The two-electron oxidized (coulometrically) solution of1(golden yellow) gives an EPR spectrum with  = 2.17 andg|| < g⊥. The reaction of PPh3with1yields the orange complex [Cu(LH2)(PPh3)](ClO4)2(4). With the assumed chemical formula, the effective magnetization of4corresponds to one electron. Its EPR spectrum in the solid state is isotropic withg = 2.07. Thisgvalue yields a theoreticalμeffof 1.80 μBat 298 K from Curie’s law, which matches very well with the experimental value of 1.89 μBat room temperature. Since single crystals of4could not be obtained, DFT calculations at the UBP86/6–311G(2d,p) level have been carried out and indicate that the cation in4is square pyramidal with the phosphine at the apex. The ease of the oxidation of the metal in1leads to the stabilization of the rare Cu(II)-P bond in4. [ABSTRACT FROM PUBLISHER]

The complex of copper(II) with N2O2Schiff base, 2,2′-[1,3-propanediyl)bis(nitriloeth-1-yl-1-ylidene)]diphenol (H2L), has been synthesized from methanol. Crystallization of the complex was conducted at room temperature (20 °C) and at 4 °C. Carrying out the crystallization process at various temperatures leads to the formation of two different complexes CuL·MeOH (1) and [{Cu2L2}{CuL}2]·2MeOH (2). The Schiff base and its complexes were characterized by elemental analysis, X-ray crystallographic techniques, spectroscopic (UV–Vis, IR), and thermal (TG\DSC) methods. Complex1crystallizes in the monoclinic space groupP21/c. The N2O2core forms a tetrahedrally distorted square-planar geometry around the metal center. Crystallization of2took place in the centrosymmetric triclinic space group (P). In the structure of2there are two crystallographically different CuIIions, one is four-coordinate in a square planar geometry, whereas the second has a five-coordinate square pyramidal geometry. The complexes are stable at ambient temperature. After heating at first they lose methanol molecules, then the organic part undergoes gradual fragmentation and combustion. [ABSTRACT FROM PUBLISHER]

Two new unsymmetrical copper(II) Schiff base complexes, [CuLn(py)] ClO4 (n = 1, 2) in which Ln represents a tridentate N2O type Schiff base ligand, were synthesized. Lns were derived from monocondensation of meso-1,2-diphenyl-1,2-ethylenediamine with salicylaldehyde or 3-methoxysalicylaldehyde. The reaction between [CuLn(py)]ClO4 and other salicylaldehyde derivatives resulted in new N2O2 unsymmetrical tetradentate CuII complexes, CuL3-6. Crystal structures of [CuL1(py)]ClO4, CuL4, and CuL5 were obtained. These new complexes as well as a series of related symmetrical ones (i.e. CuL7-12) were tested for their in vitro anticancer activity against human liver cancer cell line (Hep-G2) by MTT and apoptosis assay. All of the complexes showed considerable cytotoxic activity against tumor cell lines (IC50 = 5.13-16.24 μg mL-1). The symmetrical CuL7 was the most potent anticancer derivative (IC50 = 5.13 μg mL-1) compared to the control drug 5-FU (IC50 = 5.4 μg mL-1, p < 0.05). Flow cytometry experiments showed that the copper derivatives especially [CuL2(py)]ClO4 and CuL7 induced more apoptosis on Hep-G2 tumor cell lines compared to 5-FU. [ABSTRACT FROM AUTHOR]

Reaction of the Schiff base, 1-(4-methylimidazol-5-yl) phenylhydrazonopropane-2-one oxime (LH), with copper(II) perchlorate hexahydrate and copper(II) nitrate trihydrate in a 1 : 1 M proportion in methanol affords [Cu2L2(H2O)(ClO4)](ClO4) (1) and [Cu2L2(H2O)2](NO3)2] (2) in moderate yields. Both1and2have been characterized by elemental analysis, ESI-MS, FT-IR, UV–vis absorption spectroscopy, EPR, electric conductivity, and magnetic susceptibility measurements. The X-ray crystal structures of1·CH3COCH3and2have been determined. Both compounds are dinuclear copper(II) complexes, with each copperμ2-bridged by two oxime ligands in aμ2-η1,η2fashion. Variable temperature magnetic studies on1and2show that both compounds are dominated by an antiferromagnetic coupling through the oxime bridges. [ABSTRACT FROM AUTHOR]

Five new Ni(II) Schiff base complexes [NiLx(Solv)2] denoted by NiLx,x = 1–5, were synthesized and characterized. The Schiff base ligands were synthesized from the condensation of 5-bromo-2-hydroxy-3-nitrobenzaldehyde with different aliphatic and aromatic diamines. The X-ray crystal structure of NiL3was determined. The ligands and complexes were tested as antibacterial agents against two gram(+) and two gram(−) human pathogenic bacteria. The complexes showed moderate antibacterial activity against both gram type bacteria. The new Ni(II) complexes showed enhanced antibacterial activity compared to the previously reported Cu(II) complexes of the same ligands. [ABSTRACT FROM PUBLISHER]

Copper(II) complexes with Schiff bases derived from linear and branched amines with 2-hydroxy-1-naphthaldehyde and 3-hydroxy-2-naphthaldehyde were synthesized and characterized by IR and electronic spectroscopies, magnetic susceptibilities, electrochemistry, cyclic voltammetry (CV), X-ray diffraction, and theoretical calculations. Electronic spectra are a function of the R group on the imine nitrogen of the ligand that determines steric effects. Complexes obtained from 3-hydroxy-2-naphthaldehyde ligand are more distorted from planarity in dimethylformamide solutions than those of 2-hydroxy-1-naphthaldehyde for the same R group. As a result, the former are easier to reduce to the related copper(I) complexes than those of 2-hydroxy-1-naphthaldiminate. The structure of bis(N-i-propyl-3-hydroxy-2-naphthaldiminato)copper(II) was determined by single-crystal X-ray diffraction. Its molecular structure can be described as distorted flat tetrahedral influenced by important packing effects and is flatter than that calculated with density functional theory methods. Additional related flat tetrahedral complexes were studied by theoretical calculations and it has been found that electronic effects also play a significant role. [ABSTRACT FROM AUTHOR]

Four mononuclear complexes of Cu(II) and Zn(II) having a Schiff-base ligand and 1,10-phenanthroline/2,2′-bipyridine have been synthesized and characterized. From electronic spectral and magnetic susceptibility data, octahedral geometry has been proposed for the complexes. DNA-binding behaviors of these complexes are studied by absorption titration, electrochemical, and viscosity methods. The results indicate that the complexes bind to calf thymus DNA in an intercalative mode. The gel electrophoresis results reveal that 1 cleaves pBR322 DNA effectively. The ligand and its complexes have been screened for their antimicrobial activities against a few microorganisms. The data exhibit that they are better antimicrobial agents than the ligand. [ABSTRACT FROM PUBLISHER]

Two Schiff-base copper(II) complexes, bis(N-n-butyl-5-chlorosalicylaldiminato) copper(II) (1) and bis(N-n-butyl-4-methoxysalicylaldiminato) copper(II) (2), were synthesized and their solid-state structures were determined by X-ray crystallography. Complex 1 displays a distorted square-planar geometry, while 2 possesses square-planar geometry. Copper(II) complexes 1 and 2 showed strong inhibitory activity against jack bean urease (IC50 = 2.7, 3.5 µmol L−1), compared with acetohydroxamic acid (IC50 = 63.00 µmol L−1). A molecular modeling study was carried out via the DOCK program to gain understanding of the potent inhibitory activity of these copper species against jack bean urease. [ABSTRACT FROM AUTHOR]

Copper(II) chelates of the Schiff bases (H2L), obtained by condensation of 4-butyryl-3-methyl-1-phenyl-pyrazoline-5-one (HBMPP) with o-phenylene diamine (H2L1) and p-phenylene diamine (H2L2), have been prepared and characterized by elemental analyses, thermogravimetric analyses, magnetic measurements, diffuse reflectance spectra, IR and mass spectra, and conductance measurements. The extractability of copper(II) with H2L in chloroform was examined. Effective extraction was observed with 1 × 10-3 mol dm-3 of ligands at pH 6.5 using H2L1 and pH 7.0 using H2L2. The nature of the extracted species was ascertained by the slope analysis method. The ligand can effectively be used in solvent extraction of copper(II) from aqueous phase to organic phase. [ABSTRACT FROM AUTHOR]

A dinuclear copper(II) complex with a newly synthesized tridentate Schiff-base ligand 2-[(2-hydroxy-ethylimino)-methyl]-4,6-diiodo-phenol (HL), of formula [Cu2L2Cl2 · C4H8O] (1), was prepared. Both the ligand and the complex were characterized by X-ray crystallography, confirming that the Schiff base is tridentate and its dinuclear copper(II) complex is five-coordinate from one nitrogen and two oxygens from L and two chlorides. The complex was assayed for antibacterial (Bacillus subtilis, Staphylococcus aureus, Streptococcus faecalis, Pseudomonas aeruginosa, Escherichia coli, and Enterobacter cloacae) activities by the MTT method. Complex 1 exhibited better antimicrobial activity than the ligand. [ABSTRACT FROM AUTHOR]

A Schiff-base copper(II) complex, bis(N-n-butylsalicylaldiminato)copper(II), was synthesized and its solid-state structure was determined by X-ray crystallography. Its inhibitory activity against Helicobacter pylori urease was evaluated in vitro and it showed strong inhibitory activity against urease (IC50 = 0.95 µM), compared with acetohydroxamic acid (IC50 = 42.47 µM) as a positive reference. A docking analysis using the AUTODOCK 4.0 program was performed to explain the potent inhibitory activity of the complex against urease. [ABSTRACT FROM AUTHOR]

A new series of acyclic mononuclear copper(II) complexes have been prepared by Schiff-base condensation derived from 5-methylsalicylaldehyde, diethylenetriamine, tris(2-aminoethyl) amine, triethylenetetramine, N,N-bis(3-aminopropyl)ethylene diamine, N,N-bis(aminopropyl) piperazine, and copper perchlorate. All the complexes were characterized by elemental and spectral analyses. Electronic spectra of the complexes show a d-d transition in the range 500-800 nm, electrochemical studies of the complexes show irreversible one-electron-reduction process around -1.10 to -1.60 V. The reduction potential of the mononuclear copper(II) complexes shifts toward anodic direction upon increasing the chain length of the imine compartment. ESR spectra of the mononuclear copper(II) complexes show four lines, characteristic of square-planar geometry, with nuclear hyperfine spin 3/2. The copper(II) complexes show a normal room temperature magnetic moment value μeff = 1.72-1.76 BM, close to the spin-only value of 1.73 BM. Electrochemical and catalytic studies of the complexes were compared on the basis of increasing the chain length of the imine compartment. All the complexes were screened for antifungal and antibacterial activities. [ABSTRACT FROM AUTHOR]

An unprecedented pentanuclear hetero-bimetallic complex has been obtained by a self-assembling process between {Cu2L}2+ binuclear cationic units and [Mo(CN)8]4- anions. The compound with the formula [{C [image omitted]L}2(µ-NC)2MoIV(CN)6(CH3OH)1.5(H2O)0.5] · [{C [image omitted]L}2(µ-NC)2MoIV(CN)6(CH3OH)2] · 5H2O · 7.5CH3OH (1) (H2L = binucleating Schiff-base obtained by condensation of 2,6-diformyl-4-methylphenol with 1,3-propylenediamine), 1, crystallizes in P1 triclinic space group and consists of two pentanuclear species, [{C [image omitted]L}2(µ-NC)2MoIV(CN)6(CH3OH)1.5(H2O)0.5] (A), [{C [image omitted]L}2(µ-NC)2MoIV(CN)6(CH3OH)2] (B) and solvent. In each unit, two {Cu2L}2+ cations are bridged by one octacyanidomolybdate, via two cis-cyanido groups. Non-covalent channel motifs are developed through a complex network of supramolecular interactions (hydrogen bonds, π-π stacking interaction) involving A and B units and lattice solvent molecules. [ABSTRACT FROM AUTHOR]

Density functional theory (B3LYP/6-31G(d)) has been applied for optimization and calculation of the vibrational spectra of the compartmental hexadentate Schiff base derived from 3-formylsalicylic acid and 4,5-dichloro-1,2-phenylenediamine and 12 of its mononuclear complexes with Co(II), Ni(II), and Cu(II). Six of these complexes have the metal ion occupying the inner, N2O2, or the outer, O2O2, coordination sites in square planar geometry. The other six complexes possess octahedral geometry, occupying the inner or the outer coordination sites coordinating, additionally, to two waters. Significant changes in the ligand geometry have been observed in all complexes to permit efficient complexation with the metal. Assignments of the infrared bands are proposed based on calculations. Vibrational frequencies that are important for assignment and confirmation of the coordination sites are reported. Comparison of the total energies of the complexes reveals that inner complexes are more stable than corresponding outer complexes. Selectivity of metal ions to the coordination sites is also discussed. [ABSTRACT FROM AUTHOR]

A series of tridentate pyrazolone-based thio-Schiff bases were synthesized by the interaction of 4-acyl/aroyl pyrazolones with thiosemicarbazide in an ethanolic medium. All of these ligands were characterized on the basis of elemental analysis, infrared (IR), 1H- and 13C-NMR data. Nuclear magnetic resonance (NMR) suggests the amine-one form of ligand in solution at room temperature. Copper Schiff-base complexes, [Cu(L)(H2O)], have been prepared by the interaction of the aqueous solution of copper sulfate pentahydrate with hot ethanolic solution of the appropriate ligand. The resulting complexes have been characterized by elemental analysis, metal content determination, molar conductance, fast atom bombardment mass spectra, magnetic measurements, thermogravimetric analysis (TGA), IR, and electronic spectral studies. Thermal stability, heat capacity, and activation energy of thermal degradation for these complexes were determined by TGA, differential thermal analysis, and differential scanning calorimetry. Suitable structures are proposed for these complexes. [ABSTRACT FROM AUTHOR]

Schiff bases (L) viz, N,N',N'',N'''-tetra-3,4-dimethoxybenzalidene-3,3'-diaminobenzidine (TDBD), N,N',N'',N'''-tetra-4-hydroxy-3-methoxybenzalidene-3,3'-diaminobenzidine (THMBD), and N,N',N'',N'''-tetra-3-hydroxy-4-nitrobenzalidene-3,3'-diaminobenzidine (THNBD) afford binuclear [M2LCl4] complexes where M = Cu(II) or Zn(II). These Schiff bases and their binuclear complexes have been characterized by analytical and spectral data showing square-planar geometry on metalation with Cu2+. Intercalative binding of these complexes with DNA has been investigated by electronic absorption spectroscopy, viscosity measurements, cyclic voltammetry, and differential pulse voltammetry. Control DNA cleavage experiments using pUC19 supercoiled (SC) DNA and minor groove binder distamycin suggest that these synthesized complexes bind to the major groove. In the presence of a reducing agent like 3-mercaptopropionic acid (MPA), they show chemical nuclease activity. They also show an efficient photo-induced DNA cleavage on irradiation with a monochromatic UV light of 360 nm in the presence of inhibitors. Control experiments indicate the inhibition of cleavage in the presence of singlet oxygen quencher like sodium azide and the enhancement of cleavage in D2O show the formation of singlet oxygen as reactive species. The superoxide dismutase (SOD)-mimetic activity of the synthesized complexes has been assessed for their ability to inhibit the reduction of nitroblue tetrazolium chloride (NBT). The complexes have promising SOD-mimetic activity. The antimicrobial results indicate that the complexes inhibit the growth of bacteria and fungi more than free ligands. [ABSTRACT FROM AUTHOR]

Sulfaguanidinesalicylaldimine is a good bacteriostatic and a good complexing agent. Schiff-base complexes of Cu(II), Ni(II), Co(II), Zn(II), Cd(II), VO(IV), and UO2(VI) have been synthesized. The structural features of the complexes have been confirmed by microanalytical data, FAB mass, IR, UV-Vis, 1H-NMR, and EPR spectra. Molar conductance indicates the presence of nonelectrolytes. Spectroscopic and other analytical studies reveal the square-planar geometry for copper, square-pyramidal geometry for oxovanadium, seven-coordinate UO2(VI) complex, and octahedral geometry for other complexes. The EPR spectrum of the copper complex in the powdered form at 77 K was recorded. The redox behavior of the copper and oxovanadium complexes was studied using cyclic voltammetry. Antimicrobial activities of the compounds have been studied against microorganisms such as Escherichia coli, Staphylococcus aureus, and Candida by well-diffusion technique in DMSO. Some of the complexes have higher activity than the free ligand and the standard. [ABSTRACT FROM AUTHOR]

Two new isostructural copper(II)-zinc(II) complexes, [CuZnLBr2] (1) and [CuZnLCl2] (2) (H2L = N,N'-bis(4-methoxysalicylidene)cyclohexane-1,2-diamine), have been synthesized and characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray diffraction. Both complexes crystallize in the P-1 space group. The Cu in each complex is four-coordinate square planar with two imines and two phenolates of L. The Zn in each complex is four-coordinate tetrahedral with two phenolates of L and two halides (Br for 1 and Cl for 2). The superoxide dismutase (SOD) activity of the complexes indicates that both complexes are rudimentary models for SOD. [ABSTRACT FROM AUTHOR]

Two structurally similar trinuclear complexes, [Cu(Cu(μ-Cl)2L1)2] (1) and [Cu(Cu(μ-Cl)2L2)2] (2) (HL1 = 4-chloro-2-[(2-morpholin-4-ylethylimino)methyl]phenol, HL2 = 1-[(2-piperidin-1ylethylimino)methyl]naphthalen-2-ol), have been synthesized and structurally characterized. Both complexes are bridged trinuclear compounds. The central Cu in each complex is in an octahedral environment with two phenolate and four bridging chlorides. The symmetry-related terminal Cu in each complex is square pyramidal with one phenolate oxygen, one imine nitrogen and one amine nitrogen of the Schiff-base ligand, one Cl- in the basal plane, and one bridging Cl- in the apical position. The complexes and Schiff bases were tested in vitro for their antibacterial activities. [ABSTRACT FROM AUTHOR]

Ni(II) and Cu(II) metal complexes of simple unsymmetrical Schiff-base ligands derived from salicylaldehyde/5-methylsalicylaldehyde and ethylenediamine or diaminomaleonitrile (DMN) were synthesized. The ligands and their complexes were characterized by elemental analysis, 1H NMR, FT IR, and mass spectroscopy. The electronic spectra of the complexes show d-d transitions in the region at 450-600 nm. Electrochemical studies of the complexes reveal that all mononuclear complexes show a one-electron quasi-reversible reduction wave in the cathodic region. ESR spectra of the mononuclear copper(II) complexes show four lines, characteristic of square-planar geometry, with nuclear hyperfine spin 3/2. The copper(II) complexes show a normal room temperature magnetic moment value μeff = 1.70-1.74 BM which is close to the spin only value of 1.73 BM. Kinetic studies on the oxidation of pyrocatechol to o-quinone using the copper(II) complexes as catalysts were also carried out. The in vitro antimicrobial activity of the investigated compounds was tested against human pathogenic bacterias such as Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumonia, Pseudomonas aeruginosa and Escherichia coli. The antifungal activity was tested against Candida albicans. Generally, the metal complexes have higher antimicrobial activity than the free ligands. [ABSTRACT FROM AUTHOR]

Manganese(II), cobalt(II), and copper(II) complexes with a quinquedentate Schiff base, 2,6-diacetylpyridine bis(thiocarbohydrazone), have been synthesized and characterized by elemental analysis, molar conductance, magnetic susceptibility, and IR, 1H NMR, 13C NMR, mass (for ligand), UV and Electron Paramagnetic Resonance spectroscopies. The complexes are [M(L)X]X, where M=Mn(II), Co(II), and Cu(II), L = 2,6-diacetylpyridine bis(thiocarbohydrazone), and X= [image omitted] and Oac-. The ligand with five coordination sites forms six-coordinate complexes with octahedral geometry for manganese(II), whereas the cobalt(II) and copper(II) complexes were of tetragonal geometry. The Aiso values, nephelauxetic parameter (β), and orbital reduction factor (k) indicate the covalent nature of the metal-ligand bond. The compounds have been screened for their antipathogenic activities against Alternaria brassicae, Aspergillus niger, Fusarium oxysporum, Xanthomonas compestris, and Pseudomonas aeruginosa. [ABSTRACT FROM AUTHOR]

A new azido adduct of a tridentate Schiff-base copper(II) complex has been synthesized and characterized structurally and magnetically. X-ray single crystal structure analysis reveals that the asymmetric unit of [Cu2(L)2(µ1,1-N3)2][Cu(L)(N3)] (1) [HL = 1-(N-ortho-hydroxyacetophenimine)-2,2-diethyl-aminoethane] has two independent moieties. One of these forms a dimer, containing end-on azido bridges, with its center of inversion related equivalents. The complex crystallizes in monoclinic space group P21/c with a = 10.112(2), b = 31.938(4), c = 9.718(2) Å and β = 95.00(2)°. Variable temperature magnetic susceptibility data show antiferromagnetic interactions between copper(II) centers. [ABSTRACT FROM AUTHOR]

Adduct formation between R2SnCl2 (R = methyl and phenyl) and PhSnCl3 as acceptors and Cu(II) complexes of tetradentate Schiff-base ligands [CuL], where L = [Salen, bis(salicylaldehyde)ethylenediimine], [3-MeOSalen, N,N'-bis(3-methoxysalicylaldehyde)ethylenediimine], [5-MeOSalen, N,N'-bis(5-methoxysalicylaldehyde)ethylenediimine], [5-BrSalen, N,N'-bis(5-bromosalicylaldehyde)ethylenediimine], [salpn, N,N'-bis(salicylaldehyde)1,3-propanediimine], [Salophen, bis(salicylaldehyde)phenylenediimine], [3-MeOSalophen, N,N'-bis(3-methoxysalicylaldehyde)phenylenediimine], and [5-MeOSalophen, N,N'-bis(5-methoxysalicylaldehyde)phenylenediimine], as donors have been investigated in acetonitrile by UV-Vis spectrophotometric analysis. The formation constants and thermodynamic free energies were measured using UV-Vis titration for 1 : 1 adduct formation at various temperatures (T = 293-313 K). The trend of adduct formation for copper Schiff-base complexes with a given tin acceptor decreases as follows: [image omitted] [image omitted]; [image omitted] The trend of the reaction of RnSnCl4-n acceptors toward a given copper Schiff-base complex is PhSnCl3 > Ph2SnCl2 > Me2SnCl2. The reactivity of PhSnCl3 toward Cu(Salen), Cu(Salpn), and Cu(Salophen) increases with increasing temperature. [ABSTRACT FROM AUTHOR]

Two new copper(II) complexes, [CuL1(N3)] (1) and [CuL2(NCS)] (2) (HL1 = 4-chloro-2-[(2-piperidin-1-ylethylimino)methyl]phenol, HL2 = 4-chloro-2-[(2-morpholin-4-ylethylimino)methyl]phenol), were prepared and structurally characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray diffraction. Complex 1 is an azide coordinated mononuclear complex, while complex 2 is a terminal thiocyanate coordinated mononuclear complex. The coppers in both complexes are four-coordinate, square-planar. Both complexes show potent urease inhibitory properties. [ABSTRACT FROM AUTHOR]

Schiff-base copper(II) complexes were prepared using macrocyclic ligands, synthesized by condensation of diethylmalonate with Schiff bases derived from o-phenylenediamine and Knoevenagel condensed β-ketoanilides (obtained by the condensation of acetoacetanilide and substituted benzaldehydes). The ligands and their copper complexes were characterized by microanalytical, mass, UV-Vis, IR, 1H-NMR, ESR and CV studies, as well as conductivity data. Microanalytical, mass and magnetic moment analyses are consistent with formation of monomeric [CuL]Cl2. Spectral studies indicate square-planar geometry around copper. The smaller grain sizes found from XRD data suggest that these complexes are polycrystalline with nanosized grains. The SEM images of [CuL1]Cl2 have leaf-like morphology. The in vitro biological screening of the investigated compounds against the bacteria Escherichia coli, Klebsiella pneumoniae, Salmonella typhi, Pseudomonas aeruginosa and Staphylococcus aureus and fungi Aspergillus niger, Rhizopus stolonifer, Aspergillus flavus, Rhizoctonia bataicola and Candida albicans were tested by the well diffusion method to assess growth inhibition. A comparative study of MIC values of the Schiff-base ligands and their complexes indicate that the complexes exhibit higher antimicrobial activity than the free ligands. [ABSTRACT FROM AUTHOR]

Two copper(II) complexes [CuL1Cl]n (1) and [CuL2Cl] (2) with singly condensed tridentate Schiff-base ligands [HL1 = 6-amino-3-methyl-1-phenyl-4-azahex-3-en-1-one and HL2 = 6-diethylamino-3-methyl-1-phenyl-4-azahex-3-en-1-one] have been synthesized and structurally characterized by X-ray crystallography. Complex 1 is a single-chloro-bridged one-dimensional polymer, whereas 2 is a monomeric square-planar complex. The H-bonding interactions of the amine hydrogen and the non-bonding interactions of phenyl groups in the Schiff base play important roles for the structural variations. [ABSTRACT FROM AUTHOR]