Syntheses and Crystal Structures of Two New One-dimensional Double Hydrogen-bonding-chain Complexes [Ni(bipy)_2Cl]·ClO_4 and [Zn(bipy)_2Cl]·BF_4

Two new transition metal complexes, [Ni(bipy)2Cl]·ClO4 (bipy = 2,2'-bipyridine) 1 and [Zn(bipy)2Cl]·BF4 2, have been synthesized and characterized by single-crystal X-ray diffraction analysis. Both 1 and 2 crystallize in monoclinic space group P21/n with Z = 4. For 1, a = 10.776(1), b = 12.067(1), c = 16.146(2) , β = 93.021(2)o, V = 2031.9(4) 3, Mr = 505.98, Dc = 1.654 g/cm3, μ = 1.255 mm–1, F(000) = 1032, the final R = 0.0406 and wR = 0.1002 for 3983 observed reflections with I > 2σ(I). For 2, a = 10.758(4), b = 12.058(4), c = 16.135(5) , β = 104.57(1)o, V = 2025.7(12) 3, Mr = 500.00, Dc = 1.639 g/cm3, μ = 1.396 mm–1, F(000) = 1008, the final R = 0.0470 and wR = 0.1237 for 3759 observed reflections with I > 2σ(I). The crystal structures of 1 and 2 are isostructural with very similar supramolecular structures. A one-dimen-sional zigzag double hydrogen-bonding-chain is generated by the intermolecular M-bipy ···anion···bipy- M hydrogen bonding interactions between the chelating ligands of bipy and anion.     

Hydrothermal Synthesis,Crystal Structure and Electrochemical Properties of the Copper(II) Complex [Cu_4O_4(phen)_4(ClC_6H_4COO)_2(H_2O)_2]·(H_2O)_3

1 INTRODUCTION As we all know, copper is a necessary trace element for human body. For example, a large number of bi- nuclear or multi-nuclear transition metallic complex- es exist in active centers of some metalloprotein[1]. In the 1960’s, Bertand and Bock et al[2] reported the first tetra-nuclear copper complex with Cu4O3 unit. In 1996, a cyclo-tetranucleate complex bridged by pyridine was synthesized by Zhang Hua etc[3]. In 1999, Tan Xiangshi and coworkers[4] presented a cubic tet…     

Synthesis and Crystal Structure of a New Lanthanum(III) 4-Cyanobenzoate Complex

A new dinuclear La(III) complex [La2(4-cba)4[H(4-cba)2]2(phen)2(H2O)4] (4-Hcba = 4-cyanobenzoic acid and phen = 1,10-phenanthroline) 1 has been synthesized by solvothermal reaction in an ethanol/water mixed solution at 100 ℃ and structurally characterized by single- crystal X-ray diffraction. Crystallographic data: C88H58La2N12O20, Mr = 1881.28, triclinic P1, a = 7.518(3), b = 17.033(6), c = 17.551(6), α = 115.333(4), β = 92.9910(10), γ = 99.366(5)°, V = 1985.3(12)3, Z = 1, Dc = 1.574 g/cm3, F(000) = 944 μ = 1.145 mm–1, the final R = 0.0281 and wR = 0.0686 for 6708 reflections with I > 2σ(I). In 1, two nine-coordinated La(III) ions are connected by two 4-cba ligands in a syn-syn bidentate coordination mode, and the other six 4-cba ligands terminate the La(III) ions, resulting in an isolated dinuclear structure. Two different types of intramolecular hydrogen bonds, asymmetrical O-H…O and symmetrical O…H…O, exist in the crystal. The title complex molecules are connected through hydrogen bonds and weak π-π stacking interactions to generate a 2-D layered network. The thermogravimetric analysis of 1 has also been discussed.     

Synthesis and Structure of a Manganese(Ⅱ) Complex: [Mn_2·(dinitrobenzoic acid)_4·(1,10-phen)_2]_n

The title compound, [Mn2·(dinitrobenzoic acid)4·(1,10-phen)2]n, has a linear chain struc- ture containing binuclear [Mn2·(dinitrobenzoic acid)4(1,10-phen)2] repeat units. It crystallizes in the tricli- nic system, space group P1 with a = 7.9261(8), b = 12.1329(15), c = 14.847(2) , α = 103.845(5), β = 101.424(5), γ = 92.618(4)o, Mr = 657.37, V = 1352.3(2)3, Z = 2, Dc = 1.614 g/cm3, F(000) = 666, μ = 0.567 mm-1, the final R = 0.0407 and wR = 0.1015 for 4081 observed reflections with I > 2σ(I). The Mn atom is six-coordinated by two N and four O atoms, forming a slightly distorted octahedral geometry. All Mn–O and Mn–N bond distances range from 2.093(2) to 2.310(2) . Two adjacent octahedral units are bridged together by two pairs of bi-monodentate carboxyl groups of different dinitrobenzoic acids to form an eight-membered ring with chair-typed configuration, thus generating a one-dimensional chain along the a axis.     

Cloud point curve of nonionic surfactant related to the structures of mesoporous materials

We have investigated the phase behavior of a fluorinated surfactant R(7)(F)(EO)(7) in water. The cloud point is situated at 19 degrees C for 2 wt% of surfactant. Using this surfactant, mesoporous materials have been synthesized with micellar solution prepared either at 10 degrees C (below the cloud point) or at 40 degrees C (above the cloud point). Results show that whatever the syntheses conditions, only wormhole-like structure is recovered. The effect of perfluorodecalin addition on the fluorinated surfactant/water system was also investigated. Swollen micelles, microemulsion, and lamellar (L(alpha)) liquid crystals were identified. When perfluorodecalin is added, the cloud point is shifted toward higher temperature. As regards the mesoporous syntheses, perfluorodecalin plays a dual role. First, incorporation of perfluorodecalin leads to the formation of well ordered materials. Secondly, the pore size enlargement occurs when perfluorodecalin is added. Our results evidence that the ratio between the volume of the hydrophilic headgroup (V(H)) and the hydrophobic part (V(L)) of the surfactant is not an efficiency parameter to explain the ordering improvement of mesoporous materials and that we should rather consider the existence of the cloud point curve, which disturbs the cooperative templating mechanism (CTM).     

Interaction of CO with palladium supported on oxidized tungsten

A model catalyst system, palladium on tungsten oxide, has been examined by temperature-programmed desorption and photoemission spectroscopy. The samples were prepared by evaporation of palladium onto an oxidized tungsten foil under ultrahigh vacuum conditions. Mostly three-dimensional (3-D) palladium (Pd) clusters were found to be present on oxidized tungsten (WOx) surfaces at room temperature. Upon annealing to 670 K, the palladium clusters are redispersed and decorated by the WOx surface layer. The nature of the WOx phase on top of the palladium clusters is dependent on the mode of oxidation of the tungsten foil prior to palladium deposition. Mainly W(2+) species decorate palladium deposits on tungsten oxidized at room temperature, while mainly W(4+) species are on top of palladium deposits on the surface oxidized at 1300 K. The appearance of a Pd(n+)-O-W(4+) mixed oxide phase with n < 2 was observed on the oxidized tungsten surface. The substantial reduction (relative to nonannealed samples) of molecular CO coverage induced by annealing is discussed in terms of the changes in chemical composition and morphology of the outermost surface.     

线上零售商销售策略差异性分析及策略组合优化模型

随着线上零售业的快速发展,线上零售策略优化研究对提高线上零售商决策水平,维持线上零售业继续健康发展具有积极意义.在概述关于线上零售策略优化已有研究成果的基础上,利用数学方法严格解析了两种常用销售策略之间的联系和差异,在考虑冲量(市场份额)对消费者线上购买行为和销售量的影响的条件下,建立了线上零售商销售策略组合优化问题的非线性混合整数规划模型,并基于模型分析了零售商应该采用的销售策略优化方案.     

基于主成分分析的广东省邮电业发展状况研究

通过主成分分析方法,选取2006、2011和2016年广东省各市邮电业务数据,对广东省21个地级市的邮政和通信事业发展状况进行分析和发展水平层次划分,从时间和地域空间两个维度对广东省各地区邮电业发展情况进行排名分组.结果表明,当前广东省各地区邮电业发展状况存在显著的地区差异.     

高效且环境友好的催化剂—CMC负载稀土催化剂在一锅法合成咪唑类衍生物中的应用

CMC负载稀土催化剂是由CMC和异丙氧基稀土制得。这种固体Lewis酸催化剂被用在比较温和的条件下合成取代的咪唑类化合物。相比于昂贵的稀土Lewis酸Ln(OTf)3，廉价的CMC负载稀土催化剂也显示出了很高的催化活性。此外，这种催化剂还具有易于回收和重复使用五次以上没有明显失活的优点。     

Hydrothermal Synthesis and Crystal Structure of a New Supramolecular Channel Framework Based on Cu Complexes and Polyoxovanadate:[Cu(I)(phen)_2]_5[HV_(15)O_(36)(Cl)]_(0.65)[H_3V_(16)O_(38)(Cl)]_(0.35)·2H_2O

1 INTRODUCTION In the past years, polyoxovanadates have attracted extensive interest in solid-state material chemistry owing to the formation of mixed-valence com- pounds that exhibit rich electronic and magnetic properties relevant to catalysis, medicine and ma- terials science[1～4]. The following polyoxovanadates have been found and structurally characterized: [V5O14]3-, [V6O19]8-, [V10O28]6-, [V12O32]4-, [V13- O34]3-, [V15O36]5-, [V15O42]9-, [V17O42]4-, [V18- O42]12-, [V16O38]7…