Synthesis,structure, and DNA-binding of a new binuclear copper(II) complex: [Cu2(heap)(H2O)2](pic)2 · 2H2O

In this study, a new μ-oxamido-bridged binuclear copper(II) complex [Cu₂(heap)(H₂O)₂](pic)₂ ? 2H₂O, where heap and pic stand for the anion of N,N′-bis(N-hydroxyethylaminopropyl)oxamide and 2,4,6-trinitrophenol, respectively, has been synthesized and characterized by elemental analyses, IR, UV, molar conductance, and single-crystal X-ray diffraction. The complex has an embedded inversion center at the middle of the C–C bond of the oxamido group. Each copper(II) is in a square-pyramidal coordination geometry. The bridging ligand (heap) adopts a bis-tetradentate trans conformation and the oxamido group is in an imidic acid configuration. Hydrogen bonds contribute to a 3-D supramolecular structure in the crystal. The interaction of the binuclear complex with herring sperm deoxyribonucleic acid (HS-DNA) has been investigated by using absorption and emission spectra, electrochemical techniques, and viscometry. The results suggest that the binuclear copper(II) complex interacts with HS-DNA by electrostatic interaction with intrinsic binding constant of 2.67 × 10⁴ (mol L^?1)^?1. The influence of anions on the structure and the interaction of the binuclear complex with HS-DNA were preliminarily discussed.     

Bonding properties of copper(II)—N chromophores: Preparation,structure, and spectroscopic properties of ethylenediaminecopper(II) complexes. Molecular structure of [Cu(ethylenediamine)(pyridine)2(ClO4)2]

Summary Ethylenediaminecopper(II) perchlorate complexes of the [Cu(ethylenediamine)L₂(ClO₄)₂] type, where L = imidazole, N-methylimidazole, 2-methylimidazole, 4-methylimidazole, and pyridine, have been prepared and characterized by elemental analyses, and electronic, vibrational, and e.p.r. spectroscopic measurements. The molecular structure of [Cu(ethylenediamine)(pyridine)₂(ClO₄)₂] has been determined by three-dimensional X-ray diffraction data. The Cu^II ion is coordinated by one ethylenediamine and two pyridine ligands forming an equatorial plane, and by two perchlorate anions located on the z axis. The pyridine ligands incline at 54.9 ° to the CuN₄ plane suggesting virtually no -interaction in the complex. Similar structures with a CuN₄ coordination plane are proposed for other complexes based on the spectroscopic data. The bonding properties of these complexes are elucidated and discussed with reference to the electronic structures deduced from Gaussian analyses of their LF spectra.     

Synthesis,crystal structure,and magnetism of a dinuclear nickel(II) complex [Ni2(MOBPT)2(N3)4] · 2H2O

A dinuclear nickel(II) complex, [Ni₂(MOBPT)₂(N₃)₄] · 2H₂O (MOBPT = 4-(p-methoxyphenyl)-3,5-bis(pyridine-2-yl)-1,2,4-triazole), has been synthesized and characterized by elemental analysis, UV, IR, ESI-MS, and single crystal X-ray crystallography. The complex crystallizes in triclinic system, space group P 1 with a = 9.877(2) Å, b = 10.396(2) Å, c = 11.975(3) Å, α = 71.638(3)°, β = 74.968(3)°, γ = 64.747(3)°, V = 1044.2(4) ų, Z = 1, R = 0.0371 for 5774 observed reflections. The crystal structure determination shows that the dinuclear Ni₂N₈ unit is almost planar with each Ni²⁺ coordinated by four nitrogens from two MOBPT ligands and two axial azides in a distorted octahedral geometry. Magnetic measurements reveal weak antiferromagnetic exchange in the complex.     

Synthesis,crystal structure and properties of the dimeric copper(II) complex, [Cu2(Hboa)2(H2O)2] · (ClO4)2 (H2boa = biacetyl oxime azine)

The crystal structure of the polyhydrazone dioxime-containing dimeric copper(II) (polyhydrazone dioxime: HON=CMe[CMe=NN=CMe] _n CMe=NOH) complex, [Cu₂(Hboa)₂(H₂O)₂] · (ClO₄)₂ (1) (H₂boa = biacetyl oxime azine) has been determined. Complex (1) contains an unusual six-membered ring, which is composed of two oxime groups and two Cu^II ions. The variable temperature magnetic susceptibility of (1) in the 5–300 K range has been interpreted in terms of a Cu^II dimer. The magnetic behavior shows that the bridging six-membered ring mediates very strongly in the antiferromagnetic exchange interaction, with the fitting value J = –361(1) cm^–1 and the e.p.r. g-value of 2.193.     

Synthesis,crystal structure and magnetic properties of a 1D coordination polymer[Ni(phth)(phen)(H2O)] n · n H2O

A new one-dimensional coordination polymer [Ni(phth)(phen)(H₂O)] _n ?·?nH₂O was synthesized. The structure was determined by X-ray crystallography revealing that each nickel atom is five-coordinate bridged via phthalate ion to form a zigzag chain. The chains are further linked together via hydrogen-bonding interactions to construct a three dimensional supramolecular network. The magnetic properties of the complex show that there are weak antiferromagnetic interactions between Ni(II) centers.     

Synthesis,crystal structure and magnetic properties of the first dinuclear copper(II)–iron(II) complex [Cu(L)Fe(CN)5NO] based on nitroprusside

The nitrosyl cyanide [Cu(L)Fe(CN)₅NO] was prepared by the reaction of [Cu(L)]Cl₂ [L = 3, 10-bis(2-hydroxymethyl)-1,3,5,8,10,12-hexaazacyclotetradecane] with Na₂[Fe(CN)₅NO]·2H₂O in aqueous solution. Single-crystal analysis revealed that the title complex is the first structurally characterized dinuclear copper(II)–iron(II) complex based on the nitroprusside. Variable temperature magnetic susceptibility measurements (4.0–180.0 K) show the occurrence of very weak antiferromagnetic interactions between the copper(II) ions with zJ = –0.410 cm^–1.     

Electronic properties and crystal structure of aqua (mepirizole-oxalato)copper(II)monohydrate: [Cu(C11H14N4O2)C2O4·H2O]H2O

A Cu(ll) complex with mepirizole: 4-methoxy-2-(5-methoxy-3-methyl-pyrazoll-yl)-6-methylpyrimidine (L) and oxalate as ligands with the formula [CuL(C₂O₄)(H₂O)]·H₂O has been synthesized. The crystal structure has been determined by X-ray diffraction analysis: monoclinic, space group P2₁/n, Z = 4, a = 7.707(1), b = 14.951(3), c = 14.986(2) Å,β = 92.40(2)°, V = 1725.2(8) ų, D_m = 1.61(1) g cm⁻³, D_c = 1.62 g cm⁻³, R = 0.032 and R_w = 0.035 for 2016 observed reflections. The CuN₂O₂O′chromophore can be described as square pyramidal strongly distorted towards trigonal bipyramidal. The basal coordination positions are occupied by the two oxygen atoms of the bidentate oxalate group, the coordinated water molecule and one nitrogen atom of the bidentate mepirizole group; the other coordinated nitrogen atom occupies the apical position. Magnetic moment, IR, electronic reflectance and ESR spectra are interpreted in accordance with the proposed stereochemistry.     

Synthesis and structure of a tetranuclear copper(II) 3,5-di-tert-butylcatecholate pyridine complex, [Cu(DTBC)Py]4 · 2CH3CN

The tetranuclear copper(II)-catecholate complex, [Cu(3,5-di-tert-butylcatecholate) (pyridine)]₄ · 2CH₃CN has been isolated from the reaction between Cu(0), pyridine and 3,5-di-tert-butyl-o-benzoquinone in acetonitrile solution in nearly quantitative yield. Brown crystals of C₈₀H₁₀₆N₆O₈Cu₄ are orthorhombic, space group P2₁2₁2₁, with a = 13.395(5), b = 24.287(11), c = 24.918(11) Å, Z = 4. The crystal structure determination allows for the cluster to be formulated as four square planar Cu(II) ions, each bonded to two oxygens of chelating catecholate, a pyridine nitrogen and a bridging oxygen from a neighbouring catecholate. The Cu Cu distances range from 3.152(1) to 3.572(1) Å. The tetranuclear complex exhibits an approximate parallel stacking of two pairs of coordination planes that is suggestive of a through-space pathway for antiferromagnetic interaction. It may also have a bearing on the observed catalytic oxidation by O₂ in solution.     

Magnetic,spectroscopic and biological properties of copper(II) complexes of the tridentate ligand, α-N-methyl-S-methyl-β-N-(2-pyridyl)methylenedithiocarbazate(NNS) and the X-ray crystal structure of the [Cu(NNS)I2] complex

Copper(II) complexes of general formula, Cu(NNS)X ₂ · nH₂O (NNS = the 2-formylpyridine Schiff base of N-methyl-S-methyldithiocarbazate; X = Cl^–, Br^–, I^–, NCS^–; n = 0, 2) have been synthesized and characterized by elemental analysis and by magnetic and spectroscopic techniques. Based on magnetic and spectroscopic data, a monomeric five-coordinate square-pyramidal structure is assigned to these complexes. The crystal and molecular structure of [Cu(NNS)I₂] has been determined by X-ray diffraction. The complex has a monomeric square-pyramidal structure with the ligand coordinated to the copper(II) ion via the pyridine nitrogen atom, the azomethine nitrogen atom and the thione sulfur atom. The fourth and fifth coordination sites are occupied by the iodide ligands. Antimicrobial tests indicate that Schiff base is inactive against the bacteria, Bacillus subtilis (mutant defective DNA repair), Pseudomonas aeruginosa, methicillin resistant Staphylococcus aureus and Bacillus subtilis (wild type) and weakly active against the fungi, Candida albicans, Candida lypolytica, Saccharomyces cereviseae and Aspergillus ochraceous but its copper(II) complexes, Cu(NNS)X ₂ are strongly active against these organisms. A cytotoxicity study of the compounds against leukemic and cervical cancer cells showed that the Schiff base is inactive, but the complexes, [Cu(NNS)I₂] and [Cu(NNS)(NCS)₂] · 2H₂O exhibit significant activity against cervical cancer cells with CD₅₀ values of 4.8 and 4.2 g, respectively.     

Synthesis, crystal structure, and fluorescence properties of a novel coordination polymer [Zn(L)(4,4′-bipyridine)(H2O)] n · (H2O)4

In this work, a novel and rare coordination polymer, [Zn(L)(Bipy)(H₂O)] _n · (H₂O)₄ (H₂L??sphenylpropylmalonate acid, Bipy??4,4??-bipyridine), has been synthesized and characterized by elemental analysis, FT-IR spectroscopy, and solid fluorimetry studies. In the crystal, the Zn²⁺ ion of the complex is hexacoordinated in a slightly distorted octahedral configuration forming the unit structure, 2D structure, and 3D framework. The supramolecular architecture was constructed by a unit of (H₂O)₄ discrete water cluster. Besides, the coordination polymer displays strong emission spectra due to the metal-to-ligand charge-transfer transition, having potential applications as fluorescent materials.     

Synthesis,crystal structure,interaction with DNA,and cytotoxicity in vitro of a new mixed ligand-nickel complex: [Ni(DBMA)(en)(H2O)3]·3H2O

A mixed ligand-nickel complex of formula [Ni(DBMA)(en)(H₂O)₃]·3H₂O, where DBMA?=?2,2-dibenzyl malonic acid, en?=?ethylenediamine, has been synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction. The unit cell parameters for the complex are a?=?16.0214(16)?Å, b?=?10.0801(10)?Å, c?=?15.4024(15)?Å, β?=?108.488(2)°, V?=?2359.074(40)?ų, Z?=?4, space group P2(1)/c. The crystal system of the complex is monoclinic. Thermal stability of the water cluster by thermogravimetric analysis has been studied. Gel electrophoresis assay demonstrated the ability of the complex to cleave pBR322 plasmid DNA. The binding of the complex with HeLa cell DNA (HC-DNA) has been investigated by fluorescence spectra. Value of IC₅₀ calculated for the complex shows that the complex exhibits good cytotoxicity against HeLa and KB cell lines.     

Electrochemical properties of Hdpmta and synthesis,crystal structure as well as characterizations of a new 1D lead complex [Pb(μ 2-dpmta)2(H2O)2] n

A pyrimidine derivative, [(4,6-dimethyl-2-pyrimidinyl)thio] acetic acid (Hdpmta) has been synthesized and used as an ionophore in a Pb²⁺-selective electrode. The electrode works well over a wide range of concentration (1.0?×?10^?5 to 1.0?×?10^?2?mol?L^?1) with the response slope of 27.4?mV?decade^?1. The electrochemical behavior of Hdpmta on glassy carbon electrode shows that in 0.1?mol?L^?1 TBAP/DMF solution, it has a well-defined irreversible cathodic peak at ?0.83?V. The electrode process involves single electron transfer. Furthermore, a novel Pb(II) complex, [Pb(μ ₂-dpmta)₂(H₂O)₂] _n (1), has been synthesized through self-assembly of Pb(OAc)₂ with Hdpmta in aqueous solution and characterized by elemental analysis and IR spectra. X-ray diffraction analysis shows that 1 is a 1D chain structure consisting of two kinds of rhomboidal Pb₂O₂ rings, in which a large amount of H-bonding is involved. By π–π interactions parallel chains are further assembled to a 2D supramolecular network. The UV, TG and photoluminescence properties of 1 have also been investigated.     

Synthesis, characterization and crystal structure of tetranuclear copper(II) complex [Cu4(μ-Salophen)2(μ1,1-N3)2(N3)2] with alternating μ1,1-azido and phenoxo bridges

Tetranuclear copper(II) complex [Cu₄(??-Salophen)₂(??_1,1-N₃)₂(N₃)₂] (I) has been synthesized from the reaction of Cu(NO₃)₂ · 3H₂O with the Schiff-base ligand salophen condensed from salicylaldehyde and 1,2-phenylenediamine at the presence of a large excess of NaN₃, which has been characterized by elemental analyses, FT-IR spectroscopy, and single-crystal X-ray diffraction. X-ray diffraction studies show that I is a tetranuclear Cu(II) complex with a pair of end-on (EO) azido ions bridging the copper(II) ions in a central Cu(??_1,1-N₃)₂Cu core and one phenoxo bridging the copper(II) ions in a Cu(??-Salophen)Cu core. All copper(II) ions in I are four coordinated and adopt approximate square planar coordination geometry.     

X-ray crystal structure and properties of the [Mo(CN)2O(acetam)] · 2.5H2O complex

The X-ray crystal structure and properties of the [Mo(CN)₂O(acetam)] · 2.5H₂O {acetam = N-[1-(pyridin-2-yl)-ethylidene]diethanetriamine} complex are described. The complex was prepared by the in situ reaction of [Mo(CN)₄O(H₂O)]^2–, 2-acetylpyridine and diethylenetriamine in aqueous solution. The complex is seven coordinated. The Mo atom having a distorted pentagonal bipyramid arrangement with a tetradentate 'half-unit' Schiff base and oxygen ligand in a plane. The properties of the salt, i.r., u.v.–vis. spectra and cyclic voltammetry measurements are described and compared with those of [Mo(CN)₂O(diaceen)] · H₂O {diaceen = N,N-bis[1-(pyridin-2-yl)ethylidene]ethane-1,2-diamine) having the same coordination number for the metal.     

Coordination polymer of lanthanum: synthesis,properties and crystal structure of [La(4,4′-bipyridine)(CCl2HCOO)3(H2O)] n

A new mixed ligand complex of general formula [La(H₂O)(4,4′-bpy)(CCl₂HCOO)₃] _n has been synthesized and characterized by elemental and thermal analysis, IR spectroscopy and conductivity studies. The crystal and molecular structure was determined. The lanthanum atom is ten coordinate by four oxygen atoms from two chelating tridentate dichloroacetate substituents, two oxygen atoms from two bidentate bridging dichloroacetate groups, two oxygen atoms from two bridging tridentate dichloroacetate substituent, one oxygen atom of water molecule and one nitrogen atom from 4,4′-bipyridyl substituent. The coordination polyhedron of central atom can be described as tetradecahedron. The molecules are built up by O–H?···?N hydrogen bonds to a two-dimensional network.     

Synthesis,crystal structure and photo-induced isomerization of [ N,N ′- bis (4-fluorobenzylidene) ethylenediamine]bromo(triphenylphosphine)copper(I) complex

Abstract

The electrochemical behavior of VOQ₂OH or [VOQ₂-OVOQ₂] (Q = 8-hydroxyquinohnate anion) has been investigated by cyclic voltammetry in acetonitnie solutions. Although both species exist simultaneously at every condition analyzed, they can be clearly differentiated by this method. The effect of trace amounts of water on the electrochemical behavior is also discussed.     

Synthesis, crystal structure, and luminescence of a new complex [Co(6,6′-Bpbc)(Phen)(H2O)] · 2EtOH

A novel complex constructed with [Co(6,6′-Bpbc)(Phen)(H₂O)] · 2EtOH (6,6′-Bpbc = 2,2′-bipyridine-6,6′-dicarboxylic acid, Phen = 1,10-phenanthroline) has been successfully synthesized and characterized by X-ray diffraction, and elementary analysis. The photoluminescence properties of this complex were also studied. In the crystal, the cobalt(II) ion adopts the formation of a heptacoordination environment, and the structure units aggregate together to give birth to the infinite 1D chains, 2D-networks, and 3D-frameworks through either hydrogen bonding or π···π-stacking interaction between the aromatic rings.