Chloridotris[μ2-2-(dimethyl­amino)­ethano­lato]-μ3-hydroxido-tri-μ2-trifluoro­acetato-tetra­copper(II) tetra­hydro­furan solvate

The title compound, [Cu4(C2F3O2)3(C4H10NO)3Cl(OH)]·C4H8O or [Cu4(TFA)3(dmae)3Cl(OH)]·THF (dmae is dimeth­yl­amino­ethano­late, TFA is trifluoro­acetate and THF is tetra­hydro­furan), has an approximate mol­ecular threefold symmetry with three equivalent {Cu(dmae)(TFA)} units bridging between a Cu—Cl and a hydroxide unit, with the latter two lying on the mol­ecular threefold axis. However, in the solid state, the tetranuclear complex has Ci symmetry. The Cu atom bonded to the Cl atom has a distorted tetra­hedral geometry. The other three Cu atoms have distorted square-pyramidal geometries with an NO4 coordination environment. The bonds within the CuNO3 base of the pyramid range from 1.953 (2) to 2.033 (3) Å, while the apical Cu—O bonds are significantly longer, ranging from 2.286 (2) to 2.377 (2) Å. The square-pyramidal geometries are augmented by weak inter­actions towards a sixth O atom, forming a highly distorted octa­hedral coordination environment [long Cu—O distances = 2.712 (2)–2.824 (2) Å]. The hydroxide group is hydrogen bonded to the tetra­hydro­furan solvent mol­ecule. One of the –CF3 groups shows minor disorder over two positions, with a refined occupancy ratio of 0.894 (4):0.106 (5)

SYNTHESIS AND CHARACTERIZATION OF Mg-Al ALLOYS FOR HYDROGEN STORAGE APPLICATIONS

Mg-Al system and 2mol% Ni additive nano catalyst in the particle size range of 30-45 nm were synthesized at relatively low temperature by thermal decomposition of co- 4 and [Ni(Bipy

Dielectric properties of (CuO,CaO₂, and BaO)y/CuTl-1223 composites

We synthesized (CuO, CaO₂, and BaO)y/Cu₀,₅Tl₀,₅Ba₂Ca₂Cu₃O₁₀–δ (y = 0, 5%, 10%, 15%) composites by solid-state reaction and characterized by x-ray diffraction, scanning electron microscopy, dc-resistivity, and Fourier transform infrared spectroscopy. Frequency and temperature dependent dielectric properties such as real and imag-inary part of dielectric constant, dielectric loss, and ac-conductivity of these composites are studied by capacitance and conductance measurement as a function of frequency (10 kHz to 10 MHz) and temperature (78 to 300 K). The x-ray diffraction analysis reveals that the characteristic behavior of Cu₀,₅Tl₀,₅Ba₂Ca₂Cu₃O₁₀–δ supercon-ductor phase and its structure is nearly undisturbed by doping of nanoparticles. The scanning electron microsco-py images show the improvement in the intergranular links among the superconducting grains with increasing nanoparticles concentration. Microcracks are healed up with the inclusion of these nanoparticles and superconduct-ing volume fraction is also increased. The dielectric properties of these composites strongly depend upon the fre-quency and temperature. The zero resistivity critical temperature and dielectric properties show opposite trend with the addition of nanoparticles in Cu₀,₅Tl₀,₅Ba₂Ca₂Cu₃O₁₀–δ superconductor matrix

Carbon Monoxide Adsorption Studies on an Ru:Mn Bimetallic Alloy System for the Determination of Active Metal Sites

A supported ruthenium:manganese bimetallic alloy system dispersed on a high surface area alumina support was prepared by the co-impregnation method. The adsorption of CO at atmospheric pressure was carried out in order to determine the number of active metal sites present. The data indicate that manganese was present as a covering layer on the surface of the ruthenium. With increasing manganese loading decreasing adsorption of CO was observed, indicating that the presence of manganese masked the active ruthenium sites responsible for CO adsorption. No CO adsorption occurred on isolated manganese sites. The data were interpreted in terms of the geometric and possible electronic effects caused by the addition of manganese