Xiao-Lan Yu

Preparation and crystal structures of bis(o-phenanthroline)(acetato)zinc(II) perchlorate and bis(2,2′-bipyridine)(pyridinioacetato)zinc(II) diperchlorate

Abstract Two mixed-ligand monomeric complexes, [Zn(phen) 2 (MeCO 2 )]ClO 4 (phen = o -phenanthroline) ( 1 ) and [Zn(bpy) 2 (C 5 H 5 NCH 2 CO 2 )](ClO 4 ) 2 (bpy = 2,2′-bipyridine) ( 2 ), have been prepared and characterized by X-ray crystallography. The zinc(II) atom in 1 is surrounded in a distorted octahedral N 4 O 2 environment with ZnN bonds at 2.100(5)–2.160(5) A and ZnO bonds at 2.156(5)–2.296(5) A, while the zinc(II) atom in 2 is coordinated in a distorted trigonal-bipyramidal N 4 O environment with ZnN bonds in the range of 2.081(5)–2.140(6) A and ZnO bond at 2.020(4) A. The OCO bond angles of the chelate and unidentate carboxylato groups are 121.3(7)° and 124.5(5)° in 1 and 2 , respectively.

Use of Additives in the Electrodeposition of Nanostructured Eu3+/ZnO Films for Photoluminescent Devices

Rare-earth ion-doped ZnO has been the focus of numerous investigations because of its unique optical properties and promising applications in optoelectronic devices. Here we presented a facile electrochemical deposition route for the controllable preparation of Eu3+/ZnO nanostructures on a large scale. The prepared Eu3+/ZnO deposits were characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, selected area electron diffraction, and X-ray photoelectron spectroscopy. Herein, the growth mechanisms of Eu3+/ZnO nanosheets and nanorods were discussed. The formation process of Eu3+/ZnO foam-like nanostructures is illuminated in this paper. The room temperature photoluminescence properties of the Eu3+/ZnO foam-like nanostructures were investigated. The sharp 4f-4f transition emissions of Eu3+ can be directly observed at 593, 617, and 698 nm. An energy transfer between ZnO and Eu3+ is shown to occur under UV excitation.

Crystal structure and magnetic properties of a new three-dimensional coordination polymer constructed from (4,4) layers based on dimeric iron(II) subunits

A new metal-organic polymer [Fe(pydc)(H2O)] (1; H2pydc = pyridine-2,5-dicarboxylic acid), has been hydrothermally synthesised and characterised by X-ray diffraction, showing that 1 is a three-dimensional framework featuring two-dimensional carboxylate-bridged layers based on canted dimeric iron(II) subunits. Magnetic measurements demonstrate that, although the carboxylate and pyridyl bridges are present in the layer, 1 exhibits only a weak antiferromagnetism.

Microstructural evolution of CeO2 from porous structures to clusters of nanosheet arrays assisted by gas bubbles via electrodeposition.

Here we report the preparation of porous CeO2 and clusters of CeO2 nanosheet arrays via a simple, efficient electrochemical approach. Gas bubbles functioning as a dynamic template were utilized in our research for the synthesis of nanosheet array clusters. The Hc and Mr values of porous CeO2 are almost the same as those of CeO2 nanosheet array clusters at 5 K, and they are about 5916 Oe and 8.83 x 10(-4) emu, respectively. However, the saturation magnetization of CeO2 nanosheet array clusters is much larger than that of porous CeO2 structures. The magnetic property of the prepared CeO2 deposits may be caused by the existence of Ce(III), indicating potential interest in the nanodevices because of their electronic and magnetic properties.

A chain-like polymeric copper(II) complex bridged simultaneously by carboxylato, hydroxo and aqua ligands

Abstract A novel chain-like polymeric copper(II) complex bridged simultaneously by μ2-carboxylato-O,O′, μ3-hydroxo and μ2-aqua ligands, [Cu3(HO)2(H2O)2(Me3NCH2CO2)4](ClO4)4·2H2O, has been prepared and characterised by X-ray crystallography. The chain is composed of triangular subunits containing two octahedrally coordination copper(II) and one tetrahderally coordinated copper(II) atom. The six-coordinated copper(II) atoms are ligated by a pair of the carboxylato oxygen atoms ( CuO = 1.980(4)–1.991(4) A ) and a pair of the μ3-hydroxo groups at the equatorial positions ( CuO = 1.984(4)–1.998(4) A ), and a pair of trans-related aqua ligands at the axial positions CuO = 2.332(5)–2.349(5) A ); another copper(II) atom is four-coordinated, being bridged to the two-six-coordinated copper(II) atoms through a pair of the μ3-hydroxo ligands ( CuO = 1.968(4) A ), and the coordination sphere is completed by two monodentate carboxylate groups ( CuO = 1.933(5) A ).

Synthesis and structure of a photoluminescent three-dimensional network [AgL(MeCN)] (L=4,5-dichloro-2-cyano-3,6-dione-1,4-cyclohexen-1-ol anion)

Abstract A three-dimensional coordination network of [AgL(MeCN)]∞ (L=4,5-dichloro-2-cyano-3,6-dione-1,4-cyclohexen-1-ol anion) has been synthesized and crystallographically characterized. The silver(I) atom in the title compound is coordinated by two chelating oxygen atoms from one L ligand and two nitrogen atoms from an MeCN ligand and a cyano group of another L ligand at the equatorial positions, and by one oxygen atom from the third L ligand at the apical direction, completing a distorted square pyramidal geometry. Each L ligand acts in μ4-mode to link three silver(I) atoms into a three-dimensional network, which shows room-temperature emission upon photoexcitation at 350 nm.

A novel two-dimensional rectangular network. Synthesis and structure of {[Cu(4,4′-bpy)(pyz)(H2O)2][PF6]2}n (4,4′-bpy = 4,4′-bipyridine, pyz = pyrazine)

The complex {[Cu(4,4′-bpy)(pyz)(H2O)2][PF6]2}n comprising two-dimensional rectangular grids with each cavity enclosed by two 4,4′-bipyridine (4,4′-bipy) and two pyrazine (pyz) ligands, which superpose in an off-set fashion to give smaller rectangular channels, has been prepared and characterized by single-crystal X-ray structural analysis.

Two mixed-valence copper(I,II) imidazolate coordination polymers: metal-valence tuning approach for new topological structures

A new metal-valence tuning synthetic approach has been utilized to generate two new mixed-valence Cu(I,II) coordination polymers Cu(2)(im)(3) and Cu(3)(im)(4)(Him = imidazole), which are an unprecedented uninodal 4-connected 4.8(5) topological net and a 4-connected (4,4) net, respectively.

Synthesis, structures and hydrolytic properties of metal complexes with 1,3-bis (4-methyl-5-imidazol-1-yl)ethylideneamino propan-2-ol

Abstract Synthesis of a polydentate ligand comprising imidazole donors, 1,3-bis[(4-methyl-5-imidazol-1-yl)ethylideneamino]propan-2-ol (BIPO), and its Zn II ( 1 ), Mn II ( 2 ), Ni II ( 3 ) and Cu II ( 4 ) complexes are reported. Single-crystal structural analysis shows that complex 1 adopts a distorted square-pyramidal coordination geometry with the basal positions occupied by the four nitrogen atoms of a tetradentate BIPO ligand and the apical position by a water molecule, complexes 2 and 3 exhibit elongated octahedral coordination geometries with the axial positions occupied by a pair of aqua molecules, whereas complex 4 exhibits an elongated octahedral geometry with the axial positions occupied by an aqua molecule and a perchlorate oxygen atom. The crystal structures of the four complexes are discussed in relation to the preference of zinc ion in carbonic anhydrase, and suggest that in the presence of nitrogen donor ligands, Zn II has a significant tendency to form a four- or five-coordination. Hydrolysis of 4-nitrophenyl acetate with complexes 1 – 3 shows that the k obs for complexes 1 , 2 and 3 were 2.74×10 −2 ± 0.01, 1.45×10 −2 ± 0.01 and 0.98×10 −2 ± 0.01 M −1 s −1 , respectively.

Syntheses, Crystal Structures, Superoxide Dismutase-Like Behaviors and Physical Properties of Four Manganese(III) Complexes with Di-Schiff Bases Derived from Salicylaldehyde and Polyamines

Four manganese(III) complexes, [Mn(salMeDPT)(O 2 CMe)] 1 , [Mn(salMeDPT)Cl]·MeCN 2 , [Mn(salEDPA)] Cl 3 and [Mn(salEDPA)](MeCO 2 ) 4 have been prepared, where the di-Schiff-base salMeDPT and salEDPA were from the (2 + 1) condensation of salicylaldehyde with 4-methyl-4-azaheptane-1,7-diamine and with 4,7-diazadecane-1,10-diamine, respectively. The four complexes have been characterized by elemental analyses and cyclic voltammetry, while complexes 1 - 3 have also been characterized by single-crystal x-ray diffraction, which reveals all the Mn(III) atoms in these complexes adopt slightly compressed octahedra with the Mn-O and Mn-N bond lengths in ranges 1.882(3)-1.890(3) and 2.021(4)-0.546(4) Å, respectively. The results of activity assay indicate that complexes 1 - 4 have moderate superoxide dismutase activities.