Synthesis,Crystal Structure and Redox Property of a Copper(Ⅱ)Complex Based on 1,1-Bis(1H-benzoimidazol-2-ylmethyl)cyclohexane

A novel mononuclear copper（Ⅱ） complex [Cu（bbmc）Cl_2]·DMF,where bbmc is 1,1-bis（1H-benzoimidazol-2-ylmethyl）cyclohexane,was synthesized and characterized by X-ray single-crystal structure analysis.The complex crystallizes in triclinic,space group P1 with a = 9.1088（5）,b = 11.0075（4）,c = 14.2326（6）A,α = 97.188（3）,β = 96.394（4）,γ = 111.430（4）°,V = 1298.73（10） A^3,Z = 2,D_c = 1.409 g/cm^3,μ（Mo Kα） = 1.074 mm^-1,F（000） = 572,S = 1.078,R = 0.0381 and w R = 0.0876 for 5593 observed reflections with I 〉 2σ（I）.The central Cu（Ⅱ） ion adopts a distorted tetrahedral geometry coordinated by two nitrogen atoms of the ligand and two chloride ions.The complex showed its thermal decomposition temperature up to 226 ℃ and exhibited an irreversible one-electron transfer process involving Cu^Ⅱ/Cu^I couple.

A Novel Copper(Ⅱ) Complex of Asymmetrically N-Functionalized 1,4,7-Triazacyclononane Ligand： Syntheses, Structure, Electrochemical Property and Biological Activities

A novel copper（Ⅱ） complex derived from 1,4,7-triazacyclononane[CuL]_2（PF_6）_3×MeCN×H_2 O was synthesized and crystallographically characterized {L = 1,4-bis（2-carbamoylethyl）-7-benzimidazole-2-yl-methyl-1,4,7-triazacyclononane}. It crystallizes in triclinic, space group P1, with a = 13.2425（13）, b = 14.0807（15）, c = 17.6798（18）, α = 86.296（2）, β = 72.773（2）, γ= 68.905（2）o, V = 2934.5（5）A^3, Z = 2, D_c = 1.611 g/m^3, F（000） = 1456, M_r = 1423.09, m = 0.920 mm^-1. The final R = 0.0671 and wR = 0.1874 for 6501 observed reflections with I 〉 2σ（I）. The structural analysis shows that the complex cation（[CuL]_2^3＋） was formed by two complex cations, namely（[CuL^3]^2＋） and [CuL_（-H）~3]~＋） through a hydrogen bond. In each complex cation, the Cu（Ⅱ） lies in a distorted square pyramidal geometry. The redox behavior was studied by cyclic voltammetry（CV） in aqueous solution which indicates a reversible one electron redox reaction. The result of UV absorption, ethidium bromide（EB） fluorescence spectra indicated that the complex binds to CT-DNA in an intercalative mode. Superoxide dismutase（SOD） activity of the complex was determined by photoreduction of NBT, and the value of IC_（50） is 5.22 μmol·L^-1.

Hydrothermal Synthesis, Crystal Structure and Magnetic Property of a Novel Pentanuclear Copper(II) Complex:[Cu_5(SIP)_2(HSIP)_2(H_2O)_(18)](H_2O)_5

The pentanuclear complex, [Cu5（SIP）2（HSIP）2（H2O）18]（H2O）5 （H3SIP = 5-sulfoisophthalic acid）, has been synthesized by the hydrothermal reaction of CuCI2 with NaH2SIP at 160 ℃, and characterized by single-crystal X-ray diffraction and IR spectrum. The crystal of the complex crystallizes in a triclinic system, space group P^-1, with a = 7.0018（5）, b = 11.9725（8）, c = 19.0424（13）A^°, α = 78.8540（10）, β = 85.1710（10）, γ = 83.6080（10）°, V = 1553.24（19）A^°^3 Z = 1, C32H60O51S4Cu5, Mr= 1706.74, Dc= 1.825 g/cm^3,μ = 1.937 mm^-1, F（000） = 869, the final R = 0.0709 and wR = 0.1503 for 4235 observed reflections with I 〉 2σ（I）. The five Cu^2＋ ions are connected by two symmetry-related tddentate SIP^3- ligands and charge-balanced by two monodentate HSIP^2- ligands, giving a discrete pentanuclear structure. The pentanuclear copper molecules are linked by hydrogen bonds to form a three-dimensional supramolecular structure. The temperature-dependent magnetic susceptibility data revealed weak ferromagnetic magnetic interactions between the Cu^2＋ ions.

Enhanced mechanical property by introducing bimodal grains structures in Cu-Ta alloys fabricated by mechanical alloying

Dispersion-strengthened copper alloys can achieve ultra-high strength,but usually at the expense of duc-tility.In this study,a strategy for overcoming strength-ductility tradeoffof Cu alloys is realized through the introduction of bimodal grains structures.Cu-Ta alloys with only 0.5 at.%Ta content were successfully prepared by mechanical alloying combined with spark plasm sintering.The samples prepared by one-step and two-step ball milling methods are named as Cu-Ta(Ⅰ)and Cu-Ta(Ⅱ),respectively.The microstructural characterizations revealed that ultra-fine equiaxed grains with uniformly dispersed Ta precipitates were obtained in the Cu-Ta alloys.High strength of 377 MPa for yield strength together with elongation of∼8%was obtained in Cu-Ta(Ⅰ).Bimodal grains structures composed of fine-grain zones and coarse-grain zones were successfully introduced into Cu-Ta(Ⅱ)by a two-step ball milling approach,and both yield strength(463 MPa)and elongation(∼15%)were significantly synergistic enhanced.The hardness values of both Cu-Ta(Ⅰ)and Cu-Ta(Ⅱ)were almost kept nearly constant with the increase of annealing time,and the softening temperatures of Cu-Ta(Ⅰ)and Cu-Ta(Ⅱ)are 1018 and 1013℃,reaching 93.9%and 93.5%T m of pure Cu(1083℃),respectively.It reveals that the Cu-0.5 at.%Ta alloys exhibit excellent thermal stability and exceptional softening resistance.Ta nanoclusters with semi-coherent structures play an essential role in enhancing the strength and microstructural stability of alloys.Bimodal structures are beneficial to the activation of back stress strengthening and the initiation and propagation of microcracks,thus obtaining the extraordinary combination of strength and elongation.This study provides a new way to fabricate dispersion-strengthened Cu alloys with high strength,high elongation,excellent thermal stability and softening resistance,which have potential application value in the field of the future fusion reactor.

Synthesis, Magnetic Property and Crystal Structure of a Ytterbium-Copper Mixed Metal Complex:Yb_2Cu_3L_6·6H_2O (L=O(CH_2COO)_2)

Reaction of hydrated ytterbium nitrate and copper nitrate with diglycolic acid at pH= 7 produced a new Yb-Cu mixed metal complex, Yb2Cu3L6. 6H2O(L= O(CH2COO)2). Complex Yb2Cu3O36C2H36 (Mr= 1437. 23) crystallized in hexagonalP6/mcc (No. 192) with cell parameters of a= 14. 344 (3), c= 15. 470(7) A,V= 2757(2) A 3; Z= 2; F(000) = 1390; Dcalc.= 1- 731 g/cm3 μ(MoKa) =45. 8 cm-1. The final agreernent factors are R= 0. 077 and Rw = 0.089 for 867 observed reflections with I>3δ(I). It has been characterized by elemental analysis, IR spectrum, magnetic measurement and X-ray crystallography. In the complex, the Yb3+ ion is 9-coordinated tothree ether oxygen and six carboxylate oxygen atoms from three ligands, the copper ionis coordinated to four oxygen atoms from four carboxylate groups of four ligands andtwo water molecules. The Yb3+ ions and the Cu2+ ions are connected by the carboxylate groups of the ligands, thus resulting in the formation of the complicated networkstructure.

Effect of Cooling Rate after hot Deformation on Structure and Mechanical Properties of Low Alloy Wear Resistance Cast iron

The effect of cooling rate after 40% hot deformation on structure and mechanical properties of low alloy wear resistance cast iron was investigated by metallographic, scanning electron microscopes and detection of properties. The results show that for the cast steel after deformed, the amount of granular carbides of precipitation during the cooling decreased with the increase of the cooling rate, but the hardness was obviously enhanced, as a result, better mechanical properties will be obtained by force air cooling(cooling rate is about 7 ℃·s-1). And the reason of the change for structure and mechanical properties of the cast steel were analyzed.

Bimodal grain structure formation and strengthening mechanisms in Mg-Mn-Al-Ca extrusion alloys

The effects of small additions of calcium (0.1%and 0.5%~1) on the dynamic recrystallization behavior and mechanical properties of asextruded Mg-1Mn-0.5Al alloys were investigated.Calcium microalloying led to the formation of Al_(2)Ca in as-cast Mg-1Mn-0.5Al-0.1Ca alloy and both Mg_(2)Ca and Al_(2)Ca phases in Mg-1Mn-0.5Al-0.5Ca alloy.The formed Al_(2)Ca particles were fractured during extrusion process and distributed at grain boundary along extrusion direction (ED).The Mg_(2)Ca phase was dynamically precipitated during extrusion process,hindering dislocation movement and reducing dislocation accumulation in low angle grain boundaries (LAGBs) and hindering the transformation of high density of LAGBs into high angle grain boundaries (HAGBs).Therefore,a bimodal structure composed of fine dynamically recrystallized (DRXed) grains and coarse un DRXed regions was formed in Ca-microalloyed Mg-1Mn-0.5Al alloys.The bimodal structure resulted in effective hetero-deformation-induced (HDI) strengthening.Additionally,the fine grains in DRXed regions and the coarse grains in un DRXed regions and the dynamically precipitated Mg_(2)Ca phase significantly enhanced the tensile yield strength from 224 MPa in Mg-1Mn-0.5Al to335 MPa and 352 MPa in Mg-1Mn-0.5Al-0.1Ca and Mg-1Mn-0.5Al-0.5Ca,respectively.Finally,a yield point phenomenon was observed in as-extruded Mg-1Mn-0.5Al-x Ca alloys,more profound with 0.5%Ca addition,which was due to the formation of (■) extension twins in un DRXed regions.

Microstructures and properties of Al_2O_3 dispersion-strengthened copper alloys prepared through different methods

Al2O3 dispersion copper alloy powder was prepared by intemal oxidation, and three consolidation methods--high-velocity compaction （HVC）, hot pressing （HP）, and hot extrusion （HE）--were used to prepare Al2O3 dispersion-strengthened copper （Cu-Al2O3） alloys. The microstructures and properties of these alloys were investigated and compared. The results show that the alloys prepared by the HP and HE methods exhibited the coarsest and finest grain sizes, respectively. The alloy prepared by the HVC method exhibited the lowest relative density （98.3% vs. 99.5% for HP and 100% for HE）, which resulted in the lowest electrical conductivity （81% IACS vs. 86% IACS for HP and 87% IACS for HE）. However, this alloy also exhibited the highest hardness （77 HRB vs. 69 HRB for HP and 70 HRB for HE）, the highest compressive strength （443 MPa vs. 386 MPa for I/P and 378 MPa for HE）, and the best hardness retention among the investigated alloys. The results illustrate that the alloy prepared by the HVC method exhibits high softening temperature and good mechanical properties at high temperatures, which imply long service life when used as spot-welding electrodes.

Structure and Property of AgLaY Alloy

The structure of RE-Ag alloy was observed and analyzed using electron probe. The property changes of the alloy containing two rare earth elements AgLaY during cold forming and the high temperature softening-resistance during annealing were studied using Vickers hardness tester. The distribution and action of the rare earth elements in Ag-alloy were also analyzed. Experimental results show that AgLaY alloy has more remarkable work-hardening effect than AgLa and pure silver, and it also has better thermal-resistance. The effects of RE elements, La and Y, on the properties of Ag-alloy are attributable to their symbiotic distribution and complementary function. Because of the common properties of La and Y as RE elements, they have the completely similar distribution in Ag-alloy. At the same time, La and Y make full use of complementary role in the alloy since they belong to different periods in periodic table and have differences in atomic structure and properties.

Microstructure and properties of novel quinary multi-principal element alloys with refractory elements

Five equiatomic alloys(Ti Zr Hf VNb, Ti Zr Hf VTa, Ti Zr Nb Mo V, Ti Zr Hf Mo V and Zr Nb Mo Hf V) composed of five elements with high melting temperature, respectively were prepared by arc-melting to develop a novel high temperature alloy. The five alloys exhibit different dendritic and interdendritic morphologies. The Ti Zr Hf VNb, Ti Zr Hf VTa and Ti Zr Nb Mo V alloys formed disordered solid solution phases with body-centered cubic structure, and exhibited high compressive strength and good plasticity. The Ti Zr Hf Mo V and Zr Nb Mo Hf V alloys are composed with Laves phase(Hf Mo2) and disordered solid solution phases with body-centered cubic structure. The Ti Zr Hf Mo V and Zr Nb Mo Hf V alloys are harder and more brittle than the other three alloys due to the existence of hard and brittle Laves phases. At high temperatures, the strength decreases to below 300 MPa for the Ti Zr Hf VNb and Ti Zr Hf Mo V alloys. Solution strengthening is the primary strengthening mechanism of the Ti Zr Hf VNb, Ti Zr Hf VTa and Ti Zr Nb Mo V alloys, and brittle Laves phase is the main cause for the low ductility of the Ti Zr Hf Mo V and Zr Nb Mo Hf V alloys.

Phase structure and electrochemical properties of laser sintered La_2MgNi_9 hydrogen storage electrode alloys

Phase structure and electrochemical properties of laser sintered La2MgNi9 alloys were studied. The sintered alloys contained a main phase, LaNi5, and a ternary La-Mg-Ni phase, with a PuNi3 structure and a small amount of LaMgNi4. The ternary La-Mg-Ni phase with a PuNi3 structure had the composition of La1.8Mg1.2Ni9 and La2MgNi9, for alloys laser sintered at 1000 and 1400 W, respectively. Owing to further reactions between LaNi5 and LaMgNi4, the amount of the PuNi3 phase increased for alloys sintered at 1400 W. Both alloys had good activation property （three charge/discharge cycles）. The discharge capacities of the sintered alloys were 321.8 and 344.8 mAh/g, respectively. Compared with the alloy laser sintered at 1000 W, the poor cyclic stability of the alloy sintered at 1400 W was mainly attributed to the lower corrosion resistance of the La2MgNi9 phase.

CRYSTAL STRUCTURE AND ELECTROCHEMICAL PROPERTIES OF Zr(Mn_(1-x)Ni_x)_2(0.40≤x≤0.75) HYDROGEN STORAGE ALLOYS

The crystal structure, phase abundance and the electrochemical properties of Zr(Mn1-x Nix)2 (0.40 ≤x≤0.75) alloys were investigated by means of XRD, Rietveld refinement method and electrochemical measurements. The alloys are multiphase. C15 Laves phase occurs as a main phase accompanying with C14 phase and other minor phases, indicating that Ni element is C15-stabilized element for ZrMn2 alloy. The phase abundance and lattice parameters of Laves phase are influenced significantly by Ni substitution. The Zr(Mn0.45 Ni0.55)2 alloy with the highest amount of C15 phase exhibits the maximum electrochemical capacity of 242m Ah/g. C14 phase occurring in Zr-Mn-Ni alloys is beneficial for the electrochemical kinetics of hydride electrodes.

MICROSTRUCTURE-PROPERTY RELATIONSHIP OF Al-2.2Li-2.5Cu-0.2Mg ALLOY

The relationship among the microstructures,properties and the phase transformation in Al-2.2Li-2.5Cu-0.2Mg alloy after various treatments have been studied by optical microscopy and TEM observations.It is verified that solution treated at 525℃ for 1h is saris- factory for this alloy in which all the alloying elements are dissolved in the α-Al matrix,and aging at 190℃ for 16 h is the peak-aged condition.The alloy subjected to treatment is strengthened only be T_1 phase.In overaged or underaged conditions,the alloy is strengthened by two phases,in this cases,the strengthening effect is smaller than that by one phase.The deformation prior to aging would develop the plasticity and do not decrease the strength of the experimental alloy.

A density functional theory study of the electronic structures and magnetic properties of Fe_((1-x))Co_x alloy nanowires encapsulated in (10,0) carbon nanotubes

Under the generalized gradient approximation, the electronic structures and magnetic properties of Fe（1-x）Cox alloy nanowires encapsulated inside zigzag （10,0） carbon nanotubes （CNTs） are investigated systematically using firstprinciple density functional theory calculations. For the fully relaxed Fe（1-x）Cox/CNT structures, all the C atoms relax outwards, and thus the diameters of the CNTs are slightly increased. Formation energy analysis shows that the combining processes of all Fe（1-x）Cox/CNT systems are exothermic, and therefore the Fe（1-x）Cox alloy nanowires can be encapsulated into semiconducting zigzag （10,0） CNTs and form stable hybrid structures. The charges are transferred from the Fe（1-x）Cos nanowires to the more electronegative CNTs, and the Fe-C/Co-C bonds formed have polar covalent bond characteristics. Both the spin polarization and total magnetic moment of the Fe（1-x）Cox/CNT system are smaller than those of the corresponding freestanding Fe（1-x）Cox nanowire, and the magnetic moment of the Fe（1-x）Cox/CNT system decreases monotonously with increasing Co concentration, but the Fe（1-x）Cox/CNT systems still have a large magnetic moment, implying that they can be utilized in high-density magnetic recording devices.

Surface Structure and High-frequency Magnetic Properties of the Amorphous [Co_(0.94-x)Fe_(0.06)(MoMn)_x]_(77)(SiB)_(23) Alloys

The relationship between the high-frequency magnetic properties and surface structure of the amorphous [Co_(0.94-x)Fe_(0.06)(MnMo)_x]_(77)(SiB)_(23) alloys annealed at 400-500℃ then control-cooled was investigated using XRD,TEM and XPS techniques.The results have shown that the high-frequency losses of the present alloys ob- viously reduced after suitable treatment.A crystalline layer with ultrafine grains of γ-Co formed on the surface of the amorphous ribbons.The size of the grains is 10-20 nm.The thickness of the layer is less than 0.1 μm.The sur- face of the crystalline layer is covered with an extremely thin oxide film which is very uniform and dense with thickness of less than 30 nm,the size of grains of the oxide is less than 10 nm.These ultrafine grains and the dense oxide film effectively refine the magnetic domains and increase the resistance of the layers of the magnetic core,consequently the losses at high frequency are fairly reduced.

Syntheses, Crystal Structure and Magnetism of a Hexanuclear Copper(II) Cluster with the Unique Two-parallel Three-site Strings Configuration

Treatment of a heptadentate ligand 2,2＇-（（（pyridine-2,6-diyl-bis（methylene））- bis（（pyridin-2-ylmethyl）azanediyl））bis（methylene））diphenol （H2L） possessing pyridinyl- and phenolate groups, with three equivalents of Cu（C104）2·6H2O in methanol under base conditions, gave rise to a hexanuclear cluster complex [Cu6L2（OH）4]（C104）4·4MeCN·0.5MeOH （1）. Complex 1 crystallizes in triclinic, space group Pi with a = 12.068（12）, b = 12.567（12）, c = 16.279（16） A, α = 105.694（12）, β = 93.631（13）, γ = 112.017（11）°, V= 2166（4） A3, Z = 1,μ= 1.651 mm^-1, Dc = 1.599 Mg/m^3, T = 296（2） K, C74.5H795N14O24.5Cl4Cu6, Mr = 2086.12, F（000） = 1062.5, S = 1.061, R = 0.0521 and wR = 0.1270. In the cation of complex 1, the six copper cores are arranged into a two-parallel three-site strings configuration with each metal exhibits a slightly distorted square-pyramidal geometry, resulting from the connection of donor pyridinyi nitrogen and phenolate oxygen atoms in ligand H2L, and/or the oxygen donors in hydroxyl groups. In addition, magnetic susceptibility measurements revealed complex 1 displayed antiferromagnetic coupling.

Hydrothermal Synthesis,Crystal Structure and Electrochemical Properties of a New Dinuclear Copper Complex [C_2H_6ON]_2[Cu_2Cl_2(μ-CH_3COO)_4]

The hydrothermal reaction of copper chloride dihydrate and 5,5-dimethyl-imidazolidine,-2,4-dione with a mole ratio of 1：1 in acetonitrile resulted in the formation of a new acetate-bridged dinuclear copper complex, [C2H6ON]2[Cu2Cl2（μ-CH3COO）4]. Protonated acetamide in eaolie form and acetic acid were yielded by the hydrolysis of acetonitrile under hydrothennal condition. The rifle complex （C12H24Cl2Cu2N2O10） was characterized by X-ray single-crystal diffraction, IR spectrum, elemental and electrochemical analysis. It crystallizes in the monoclinic system, space group P21/c with a = 8.298004）, b = 14.358（2）, c = 12.0010（2） A^°, β= 130.620（3）°, V = 1085.3（2） A^°^3, Dc = 1.696 g/cm^3, 34, = 554.31, Z = 2, F（000） = 564 and μ = 2.254 mm^-1. The crystal structure consists of a tetraacetate-bridging dinulcear copper complex anion [Cu2Cl2（μ-CH3COO）4]^2-, with the chlorine anions in the axial positions, and two protonated acetamide cations [C2H6ON]^＋, which were connected through hydrogen bonds to form a three-dimensional infinite network.

Effect of stoichiometry and Cu-substitution on the phase structure and hydrogen storage properties of Ml-Mg-Ni-based alloys

To improve the electrochemical properties of rare-earth-Mg-Ni-based hydrogen storage alloys, the effects of stoichiometry and Cu-substitution on the phase structure and thermodynamic properties of the alloys were studied. Nonsubstituted Ml0.80Mg0.20（Ni2.90Co0.50-Mn0.30Al0.30）x （x=0.68, 0.70, 0.72, 0.74, 0.76） alloys and Cu-substituted Ml0.80Mg0.20（Ni2.90Co0.50-yCuyMn0.30Al0.30）0.70 （y=0, 0.10, 0.30, 0.50） alloys were prepared by induction melting. Phase structure analysis shows that the nonsubstituted alloys consist of a LaNi5 phase, a LaNi3 phase, and a minor La2Ni7 phase;in addition, in the case of Cu-substitution, the Nd2Ni7 phase appears and the LaNi3 phase vanishes. Ther-modynamic tests show that the enthalpy change in the dehydriding process decreases, indicating that hydride stability decreases with in-creasing stoichiometry and increasing Cu content. The maximum discharge capacity, kinetic properties, and cycling stability of the alloy electrodes all increase and then decrease with increasing stoichiometry or increasing Cu content. Furthermore, Cu substitution for Co ame-liorates the discharge capacity, kinetics, and cycling stability of the alloy electrodes.

Phase structure and hydrogen storage properties of LaMg_(3.70)Ni_(1.18) alloy

The phase structure and hydrogen storage properties of LaMg 3.70 Ni 1.18 alloy were investigated. The LaMg 3.70 Ni 1.18 alloy consists of main LaMg 2 Ni phase, minor La 2 Mg 17 and LaMg 3 phases. The alloy can be activated in the first hydriding/dehydriding process, and initial LaMg 2 Ni, La 2 Mg 17 , and LaMg 3 phases transfer to LaH 2.34 , Mg, and Mg 2 Ni phases after activation. The reversible hydrogen storage capacity of the LaMg 3.70 Ni 1.18 alloy is 2.47 wt.% at 558 K, which is higher than that of the LaMg 2 Ni alloy. The pressure-composition-temperature （PCT） curves display two hydriding plateaus, corresponding to the formation of MgH 2 and Mg 2 NiH 4 . However, only one dehydriding plateau is observed, owing to the synergetic effect of hydrogen desorption between MgH 2 and Mg 2 NiH 4 . The uptake time for hydrogen content to reach 99% of saturated state is less than 250 s, and 90% hydrogen can be released in 1200 s in the experimental conditions, showing fast kinetics in hydriding and dehydriding. The activation energies of the LaMg 3.70 Ni 1.18 alloy are –51.5 ± 1.1 kJ/mol and –57.0 ± 0.6 kJ/mol for hydriding and dehydriding, respectively. The hydriding/dehydriding kinetics of the LaMg 3.70 Ni 1.18 alloy is better than that of the Mg 2 Ni alloy, owing to the lower activation energy values.