Electrocatalytic oxidation of methanol at platinum electrode modified with Eu-Fe cyanide-bridged binuclear complexes

The electrocatalytic oxidation of methanol at the platinum electrode modified with Eu-Fe cyanide-bridged binuclear complexes (Eu-Fe film) was investigated for the first time by cyclic voltammetry.Compared with the bare platinum electrode,the results showed that the modified electrode had excellent electrocatalytic activity for the oxidation of methanol;the oxidation peak potential shifted more negatively and the peak current increased about twenty times.The electrooxidation of methanol at the modified elect...

ORGANOMETALLIC FERROELECTRIC LIQUID CRYSTALS Ⅰ. LIQUID CRYSTAL PROPERTIES OF ORTHO—PALLADATED BINUCLEAR COMPLEXES OF AZINE, IMINE AND AZO DERIVATIVES

The mesomorphie properties of title complexes are investigated by means of DSC and polarizing microscopy. The mesophase temperature ranges of complexes are wider than that of corresponding organic ligands. The bridging groups of the complexes have profoand effects on the mesomorphic behavior, When the bridging groups are opticallhy active. the compleve show chiral smectic

Synthesis and Magnetism of μ-IsophthalatoOxovanadium(Ⅱ) Binuclear Complexes

Two μ-isophthalato oxovanadium(Ⅱ) binuclear complexes, [(VO)2-(IPHTA) (phen)2] SO4 (1) and [(VO)2 (IPHTA) (NO2-phen)2 ]SO4 (2) were syn thesized and characterized. The magnetism of complex (1) was studied

Synthesis and magnetic properties of μ-phenolato copper (Ⅱ) binuclear complexes with different exogenous bridges

The syntheses and magnetic properties are reported for a series of copper(Ⅱ) complexes prepared from a pentadentate binucleating ligand 2,6-diformyl-4-methylphenol di(benzoyl-hydrazone) (H3L). These complexes incorporate different exogenous ions (X-) into a bridging position to form copper(Ⅱ) binuclear complexes of the formula [Cu2(H2L)X]2+, where X-= Br-(1), Cl-(2), HO-(3), C2H5O-(4) and C3H3N2- (5). The complexes have been characterized with variable temperature magnetic susceptibility (4.2-300 K) and the observed data were fit to those from a modified Bleaney-Bowers equation by least-squares method, giving the exchange integral 2J = -6.2 cm-1 for 1, -76.4 cm-1 for 2, -241.9 cm-1 for 3, -231.1 cm-1 for 4 and -343.8 cm-1 for 5. This suggested that there is an antiferromagnetic interaction between the Cu(Ⅱ) ions and the sequence of the effect of some exogenous bridging ligands on magnetic coupling is corresponding to that in spectrochemical series.

Ab Initio Molecular Orbital Calculation on Dinuclear Gold(Ⅰ) Complexes──Metal-Metal Interaction and Electronic Structure of Binuclear Gold(Ⅰ) Complexes with Bridging Bidentate Ligands

The electronic structure and electronic absorption spectra of binuclear Au(Ⅰ) complexes with bidentate phophines and a bidentate ylid ligand have been studied using quasirelativistic pseudopotential ab initio calculations at the HF and MP2 levels by the LANL2DZ basis sets. The electronic properties of the spectral transition and Au(Ⅰ)—Au(Ⅰ) interaction were also discussed.

Synthesis, Characterization and Biological Activities of Binuclear Metal Complexes of 2-Benzoylpyridine and Phenyl(Pyridin-2-yl) Methanediol Derived from 1-Phenyl-1-(Pyridin-2-yl)-N-(Pyrimidin-2-yl) Methanimine Dihydrate Schiff Base

The Schiff base, 1-phenyl-1-(pyridin-2-yl)-N-(pyrimidin-2-yl)methanimine dihydrate (L1) has been synthesized by the condensation reaction between 2-aminopyrimidine and 2-benzoylpyridine and characterized using 13C-NMR, 1H-NMR, microanalysis, FT-IR, DEPT-135, HSQC, HMBC, COZY, NOESY. The reaction of 1-phenyl-1-(pyridin-2-yl)-N-(pyrimidin-2-yl)methanimine dihydrate (L1) with salts of V(IV), Co(II) and Cu(II), however, resulted in the hydrolysis of L1 to give binuclear metal complexes of 2-benzoylpyridine (L2) and phenyl(pyridin-2-yl)methanediol (L3) which were characterized using UV-visible spectroscopy, and TGA. The single crystal x-ray structure determined for the Copper(II) complex revealed that we obtained a compound previously obtained using a different method of synthesis. The Schiff base ligand (L1) is soluble in methanol, ethanol, DMSO, acetone and DMF. Microanalysis and Spectroscopic studies indicated that binuclear metal complexes were obtained by the coordination of metal ion to 2-benzoylpyridine (L2) and phenyl(pyridin-2-yl)methanediol (L3) from the hydrolysis of L1. Spectroscopic and elemental analysis reveal the formation of square pyramidal complexes of Co(II) and Cu(II) and a square planar complex of V(IV). In vitro antibacterial and antifungal activity against three bacterial strains (Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus) and three fungal stains (Candida albicans, Candida glabrata and Candida parapsilosis) showed moderate biological activity. Antioxidant studies reveal that only the binuclear Co(II) and oxovanadium(II) complexes are potent to eliminate free radicals.

Synthesis and magnetism of rare earth (Nd,Gd,Dy,Ho,Er,Y) pentafluoropropionate binuclear complexes with 2-(4'-methoxy-phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide

Six compounds of the general formula [Ln(pfpr)3]2(NITPhOMe).nH2O, where Ln=Nd, Gd, Dy, Ho, Er, Y, pfpr=pentafluoropropionate, NITPhOMe=2-(4'-methoxyphenyl)-4,4,5, 5-tetra-methylimidazoline-1-oxyl-3-oxide, and n=4 (for Nd, Dy, Er); 3 (for Gd); 6 (for Ho); 5 (for Y), have been synthesized. These complexes were characterized by elemental analyses, IR, electronic spectra and molar conductances. The variable temperature (4-300 K) magnetic susceptibility of the complex [Gd(pfpr)3]2(NITPhOMe).3H2O was determined. The observed susceptibility data were fit to those from theoretical magnetic equation by least-squares method. The exchange integral, J, was found to be equal to 2.14 cm-1. This indicates a weak ferromagnetic spin-exchange interaction between the radical and the gadolinium(III) ion.

Synthesis and magnetic properties of copper(Ⅱ)-lanthanoid(Ⅲ) binuclear complexes with N,N'-bis(3-aminopropyl) oxamido ligand

Six novel u-oxamido binuclear complexes, namely Cu(oxpn)Ln(L)2(ClO4)3 (Ln: Eu, Gd, Tb, Nd, Ho, Er), where oxpn is N,N'-bis(3-aminopropyl) oxamido, L denotes 5-nitro-1,10-phenanthroline (abbreviated as NO2-phen), have been synthesized and characterized. The magnetic susceptibility of complexes Cu(oxpn)Gd(NO2-phen)2(ClO4)3.2H2O was measured over the 4-300 K and the observed data were successfully simulated by equation based on spin Hamil-tonian operator (H = -2JS1.S2), giving the exchange integral J(Cu-Gd)=-1.62 cm-1. This indicates a weak antiferromagnetic interaction between the Cu(Ⅱ) and Gd(Ⅲ) ions.

Synthesis and Characterization of Binuclear Lanthanide Complexes with Macrocyclic Schiff Base Derived From 2,6-Diacetylpyridine and 1,3-Diamino-2-hydroxypropane

Nine homobinuclear lanthanide complexes with macrocyclic Schiff base were prepared by condensing 2, 6-diacetylpyridine and 1, 3-diamino-2-hydroxypropane in the presence of template lanthanide metal ions. These complexes were characterized by elemental analysis, IR, molar conductance and magnetic susceptibility. The variable-temperature magnetic susceptibility (4-300 K) of complexes of Gd( Ⅲ ) and Dy( Ⅲ ) was determined. A satisfactory fit to theoretical curve derived from spin Hamiltonian operator was obtained using least-squares method. The exchange interaction parameters are J=-0.26 cm-1, g=1.98 and △=0.06 cm-1, Z.J'=-0. 21 cm-1,g'=1.33 for Gd( Ⅲ ) and Dy( Ⅲ ), respectively. The results indicate a very week antiferromagnetic interaction between Gd( Ⅲ )-Gd( Ⅲ ) and Dy( Ⅲ )-Dy( Ⅲ ) ions.

Ligand Effects in Dinitrogen Hydrogenation of Binuclear Zirconium Complexes

In this work, we report a theoretical exploration of the ground-state electronic structures and molecular vibrational properties of a series of binuclear zirconium complexes in the framework of density functional theory （DFT） employing the B3LYP hybrid functional. The calculated results reveal that the electronic structure of the complex [（η^5-C5Me5）2Zr]2（μ^2, η^2, η^2-N2） is unfavorable for hydrogenation due to the exclusion of side-on dinitrogen in the LUMO＋ 1 molecular orbital as compared with the reactant 1 [（η^5-C5Me4H）2Zr]2（μ2,η^2,η^2-N2）. Besides, the structural feature of the hypothetical intermediate 1′, [（η^5C5Me4H）2Zr]2（μ2,η^2, η^2-N2）-n2, clearly implies the possibility of further hydrogenation. In addition, the distinguishing of vibrational modes of experimental intermediate 2, [（η^5-C5Me4H）2ZrH]2（μ2,η^2,η^2-N2H2）, indicates that the asymmetric stretching of Zr-N and Zr-H leads to dissociation. Moreover, the vibrational intensity of Zr-H is stronger than that of Zr-N. Therefore, it can be predicted that excess hydrogen atmosphere is necessary to ensure the dissociation of Zr-N bonds.

Binuclear Lanthanide Complexes Containing SodiumSyntheses and Crystal Structure of (C_5Me_5)_2Nd(μ-Cl)_2Na(DME)_2 and (C_5Me_5)_2Nd(μ-OCH_3)_2Na(DME)_2

The reaction of NdCl_3 with NaC_5Me_5 generates a novel complex (C_5Me_5)_2Nd(μ-Cl)_2Na(DME)_2 (1). Then (1) reacts with 1 mol ratio Na and a little methyl-naphthalene generating another novel complex (C_5Me_5)_2Nd(μ-OCH_3)_2Na(DME)_2 (2).Complex (1) belongs to orthorhombic crystal system,space group Pbn2_1 with a=1.2635(3) nm,b=1.6127(5) nm,c=1.6543(4J nm,V=3.371(2) nm^3,D_c=1.36 gcm^(-3) and Z=4.The central metal Nd is coordinated by two C_5Me5 ring centroids and two μ-chlorine atoms forming a distorted tetrahedron.The crystal of complex (2) is monoclinic,space group C2/n with a=1.7482(5) nm, b=1.3260(4) nm,c=1.6406(7) nm,β=109.39(3)°,V=3.5874(1) nm^3,D_c=1.26 gcm^(-3) and Z=4,Two five-membered ring centroids and two p-oxygens of OCH_3 form a distorted tetrahedron around the central neodymium ion.

Syntheses, Characterizations, and Crystal Structures of Two Binuclear Silver Complexes Based on O,O'-Dialkyldithiophosphate and 1,10-Phenanthroline

Two binuclear silver complexes, [Ag2{μ-S2P（OCH2Ph）2}2（phen）2] （1） and [Ag2{μ- SEP（OCH2CH2Ph）2}E（phen）2] （2）, were synthesized and characterized by elemental analysis, infrared spectrum, thermo-gravimetric analysis and X-ray single-crystal diffraction. Complex 1 crystallizes in the triclinic system, space group P1 with a = 9.7881（4）, b = 10.7726（4）, c = 13.1952（6） A, a = 103.686（4）, ,8= 99.477（3）, ）, = 107.494（4）°, F= 1246.88（9）A3, Dc = 1.591 g.m-3 and Z = 1; Complex 2 is of monoclinic system, space group P2jn with a = 10.6014（8）, b = 24.3969（15）, c = 11.5353（10）A,β= 14.125（10）°, F= 2722.9（4） A3, Dc = 1.526 g.m-3 and Z = 2. In the molecules of 1 and 2, O,O＇-dialkyldithiophosphate anions, （PhCHEO）PS2 and （PhCH2CHEO）PS2 act as bridging ligands and connect two Ag（I） centers into a binuclear unit with AgES4P2 eight-membered rings in ＂chair＂ conformations. In both crystal structures, face-to-face π-π stacking interactions between the adjacent paralleling aromatic rings of 1,10-phenanthroline play a prominent role in the crystal packing and result in a 1D chain. And such 1D chains are further linked into 3D networks by weak intermolecular C-H...π interactions for 1.

Synthesis and magnetic studies of phthalato-bridged oxovanadium(Ⅳ) binuclear complexes

Six new μ-phthalato binuclear oxovanadium(IV) complexes,namely [(VO)2(PHTH)-(L)2]SO4 (L denotes 2,2'-bipyridine (bpy);1,10-phenanthroline (phen);4,4'-dimethyl-2,2'-bipyridine (Me2bpy);5-nitro-1,10-phenanthroline (NO2-phen);5-chloro-1,10-phenanthroline (Cl-phen) and 5-methyl-l,10-phenanthroline (CH3-phen),where PHTH is the phthalate dianion),have been synthesized and characterized by elemental analyses,IR,electronic spectra,magnetic moments at room temperature and molar conductivity measurements.The temperature dependence of the magnetic susceptibility of complexes [(VO)2(PHTH)(Phen)2]SO4 (1) and [(VO)2(PHTH)(CH3-phen)2]SO4 (2) was measured in 4-300 K range and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator,H--2JS1S2,giving the exchange integrals J=-12.8 cm-1 for 1 and J=-7.9 cm-1 for 2.This indicates an antiferromagnetic spin-exchange interaction between the metal ions within each molecule.

THE FIRST BINUCLEAR MOLYBDENUM AND TUNGSTEN COMPLEXES WITH DOUBLY-BRIDGING PYRIDINE-2-THIOLATO LIGANDS.X-RAY CRYSTAL STRUCTURE OF THE COMPLEX[Mo_2(CO)_4(μ-pyS)_2(PPh_3)_2].2C_7H_8

The title complex was obtained by reactions of [Mo(CO)_3(MeCN)_3] with [CuBr(pySH)(PPh_3)_2]or directly with pySH and PPh_3. The latter method can be used to synthesize the corresponding tungsten complex [W_2(CO)_4(μ-pyS)_2(PPh_3)_2].The molecular structure of the title compound was determined by X-ray diffraction method.

Syntheses and Magnetism of Binuclear Tb(Ⅲ)-Tb(Ⅲ)Complexes with Dianion of Chloranilic Acid as Bridging Ligand

The syntheses, spec(?) complexes are of significance for understanding mechanisms of magnetic interaction between metal ions and the exploitation of the synthesis of molecular magnetic materials. There were a few works reported previously on the syntheses and magnetic in-

Effects of binuclear copper(Ⅱ)threonine complex on blood glucose, lipids and protection of the hearts and kidneys in diabetic mice

Aim To study the effects of binuclear copper （Ⅱ） threonine complex （Cu2 （Thr）4） as analogue of superoxide dismutase （SOD） on blood glucose, blood lipids and vessels of hearts and kidneys in diabetic mice. Methods Diabetic mouse model was established by intraperitioneal injection of alloxan. Low, middle, and high doses of Cu2（Thr）4 at 0.002%, 0.02% and 0.1% were given respectively to diabetic mice following lavage. The fasting blood glucose was determined after the diabetic mice were given Cu2 （Thr）4 for 0, 30, and 45 d. The diabetic mice were killed on the 45th day. Then glycosylated hemoglobin （HbAlc） and blood lipids were assayed, and pathologic changes in hearts and kidneys stained with HE were observed. Results Compared with the control group in which the diabetic mice were given distilled water, the value of blood glucose reduced significantly in middle dose group （P 〈 0.01 ）, followed by that in low dose group （P 〈 0.05）. TC level reduced markedly and HDL level increased significantly in all three treatment groups （P 〈 0.05）. Especially in middle dose group, cardiac muscle fibers were neatly arranged, nucleus and cytoplasm well distributed, glomeruli showing normal structure, cells well distributed and staining being normal. Conclusion Cu2 （Thr）4 reduces blood glucose, regulates blood lipids, and play protective action on the vessels of hearts and kidneys in diabetic mice. The effects of it in middle dose were better than those of other doses.

Synthesis and Structural Determination of Binuclear Nine-Coordinate K_4[Y_2(Httha)_2]·14H_2O

A Y 3+ complex with triethylenetetraaminehexaacetic acid was prepared and its composition and structure were determined as K 4[Y 2(Httha) 2]·14H 2O by elemental analysis and single crystal X ray four circle diffraction analysis. In the binuclear complex, the two YN 3O 6 parts all form nine coordinate monocapped square anti prismatic structures. There are a lot of water molecules in the unit cell which form hydrogen bonds.

Synthesis and Crystal Structure of a Novel Binuclear Copper(Ⅱ) Complex, [Cu(paba)Cl]

A novel binuclear Cu（Ⅱ） complex [Cu（paba）Cl] （pabaH = 2-（2-pyridylmethylimine）benzenesulfonic acid） has been synthesized and characterized by elemental analysis, IR and single-crystal X-ray diffraction. The crystal of the title complex crystallizes in a monoclinic system, space group P21/n, with a = 6.8165（7）, b = 15.3073（16）, c = 12.3795（13） A^°, β= 95.0160（10）°, V= 1286.8（2） A^°^3, Mr = 360.26, Dc= 1.860 g/cm^3,μ = 2.074 mm^-1, F（000） = 724, Z = 4, the final R = 0.0252 and wR = 0.0675 for 2395 observed reflections with I 〉 20（I）. The title complex is centrosymmetric and a pair of chlorides act as μ2-bridges to link two Cu（Ⅱ） ions forming a binuclear complex. Every Cu（Ⅱ） ion is five-coordinated by pyridyl N, imine N and sulfonate O atoms of the tridentate paba ligand as well as two bridging Cl^-, constructing the distorted square-pyramidal geometry. In the structure extensive hydrogen bonds and weak π-π stacking stabilize the solid structures, through which the complex builds its 3-dimensional supramolecular structure.

Synthesis and Crystal Structure of an Azide Bridged Binuclear Zinc(Ⅱ) Dimer Containing Taurine Schiff Base [Zn_2(C_8H_9N_2O_3S)_2·(N_3)_2·(H_2O)_2]_2·_2H_2O

The title complex [Zn2L2（N3）2（H2O）2]·2H2O （L = N-（2-pyridylmethylidene） taurine） has been synthesized in a methanol-water solution. The crystal belongs to monoclinic, space group P2 1/C with a = 15.8064（10）, b = 10.5015（5）, c = 17.3193（11） ,A, β= 111.314（2）°, V = 2678.2 （3） ,A ^3 C16H26N10O10S2Zn2, Mr = 713.33, Z = 4, DC = 1.769 g/cm^3, μ = 2.017 mm^-1 and F（000） = 1456. The asymmetric unit consists of two half-molecules of the complex and two water molecules. Four N and two O atoms form the coordination environment of each Zn atom, resulting in a distorted octahedral configuration. The two halves of each independent dimer are related by a crystallographic inversion centre, which lies at the centre of the ring formed by two Zn atoms and the coordinating atoms of the two azide anions. The average separation of Zn（Ⅱ）...Zn（Ⅱ） is 3.322 A. The molecules are linked by O-H...O hydrogen bonds, generating an interesting zigzag infinite chain structure in the ac plane.

Synthesis and Crystal Structure of Binuclear Copper (Ⅱ) Complex Containing (Dimethylaminomethyl)ferrocene

A binuclear complex including ferrocenyl, Cu2{Fe(C5H5)[C5H4CH2N(CH3)2]}2 (CH3COO)4, was synthesized and characterized by X-ray diffraction. The title complex crystallizes in triclinic, space group P with a = 8.2779(8), b = 9.4830(8), c = 12.262(1) ? = 81.079(5), b = 80.620(4), g = 78.960(4), V = 924.4(1) 3, Z = 1, C34H46Cu2Fe2N2O8, Mr = 849.51, Dc = 1.526 g/cm3, l(MoK) = 0.71073 ? ?= 1.954 mm-1, F(000) = 438, R = 0.0297 and wR = 0.0901. Both cyclopentadienyl rings in each dmaf (dmaf = (dimethylaminomethyl)ferrocene, Fe(C5H5)- [C5H4CH2N(CH3)2]) have an eclipsed conformation. The binuclear molecule has a crystallographic centrosymmetry; four acetates and two Cu atoms form a cage structure with the distance between two neighboring Cu atoms of 2.655(1) .