The structural characteristics of different alkoxides of Y. Ba and Cu are studied with quantum chemi-cal CNDO /2 calculations. The relative hydrolysis rate coefficients k_M of them are obtained according tothe relati...The structural characteristics of different alkoxides of Y. Ba and Cu are studied with quantum chemi-cal CNDO /2 calculations. The relative hydrolysis rate coefficients k_M of them are obtained according tothe relationship between frontier orbitals and organic chemical reactions. Based on the above results. properexperimental conditions for the preparation of homogeneous ultra-purity. submicro high-T_cYBa_2Cu_3O_(7-δ) superconducting powders are proposed.展开更多
The mixed-metal cluster Yb4O4（OiPr）16Na12 has been synthesized and structurally determined by IR, elemental analysis, and single-crystal X-ray diffraction. The crystal belongs to the cubic system, space group P23 wi...The mixed-metal cluster Yb4O4（OiPr）16Na12 has been synthesized and structurally determined by IR, elemental analysis, and single-crystal X-ray diffraction. The crystal belongs to the cubic system, space group P23 with a = b = c = 13.9788（3）A, V = 2731.55（10）A3, Z = 1, Dc = 1.202 g/cm3, Mr = 1977.42,/J = 3.480 mm-1, F（000） = 972, the final R = 0.0288 and wR = 0.1511 for 1677 observed reflections with I 〉 2σ（I）. X-ray analysis reveals that Yb4O4（Oipr）16Na12 is centrosym- metric and the structure contains four ytterbium metals and twelve sodium metals, and each ytterbium atom is coordinated by six oxygen atoms. In addition, an ancillary computational analysis of the optimized molecular unit was provided. The large energy gap （3,31 eV） between HOMO and LUMO indicates that the structure framework is particularly stable.展开更多
The direct electrochemical synthesis of metal alkoxides [Ti（OEt）4, Ti（OPr-i）4, Ti（OBu）4, Ti（OEt）2（acac）, Cu（OEt）2, Cu（OBu）2, Mg（OEt）2 and Ni（OEt）2] were studied by anode dissolution of metals in abso...The direct electrochemical synthesis of metal alkoxides [Ti（OEt）4, Ti（OPr-i）4, Ti（OBu）4, Ti（OEt）2（acac）, Cu（OEt）2, Cu（OBu）2, Mg（OEt）2 and Ni（OEt）2] were studied by anode dissolution of metals in absolute ethanol in the presence of a conductive additives. The anodic behaviour of Ti electrode in ethanol was investigated by using cyclic voltammetry（CV）. These metal alkoxides were characterized by FTIR spectra. The results show that direct electrochemical synthesis of metal alkoxides have a high current efficiency and electrolysis yield. These alkoxides have a high purity and can be directly used as the precursor of nanosize oxides prepared by sol-gel procedure. The anodic behaviour of Ti electrode in alcohol is markedly the feature of the pitting corrosion. The passivation of Ti anode would occur in the presence of trace water.展开更多
文摘The structural characteristics of different alkoxides of Y. Ba and Cu are studied with quantum chemi-cal CNDO /2 calculations. The relative hydrolysis rate coefficients k_M of them are obtained according tothe relationship between frontier orbitals and organic chemical reactions. Based on the above results. properexperimental conditions for the preparation of homogeneous ultra-purity. submicro high-T_cYBa_2Cu_3O_(7-δ) superconducting powders are proposed.
基金Supported by the National Natural Science Foundation of China(No.20902001 and 21102001)the Natural Science Foundation of Anhui Province(No.090416220)the 211 Project of Anhui University
文摘The mixed-metal cluster Yb4O4（OiPr）16Na12 has been synthesized and structurally determined by IR, elemental analysis, and single-crystal X-ray diffraction. The crystal belongs to the cubic system, space group P23 with a = b = c = 13.9788（3）A, V = 2731.55（10）A3, Z = 1, Dc = 1.202 g/cm3, Mr = 1977.42,/J = 3.480 mm-1, F（000） = 972, the final R = 0.0288 and wR = 0.1511 for 1677 observed reflections with I 〉 2σ（I）. X-ray analysis reveals that Yb4O4（Oipr）16Na12 is centrosym- metric and the structure contains four ytterbium metals and twelve sodium metals, and each ytterbium atom is coordinated by six oxygen atoms. In addition, an ancillary computational analysis of the optimized molecular unit was provided. The large energy gap （3,31 eV） between HOMO and LUMO indicates that the structure framework is particularly stable.
文摘The direct electrochemical synthesis of metal alkoxides [Ti（OEt）4, Ti（OPr-i）4, Ti（OBu）4, Ti（OEt）2（acac）, Cu（OEt）2, Cu（OBu）2, Mg（OEt）2 and Ni（OEt）2] were studied by anode dissolution of metals in absolute ethanol in the presence of a conductive additives. The anodic behaviour of Ti electrode in ethanol was investigated by using cyclic voltammetry（CV）. These metal alkoxides were characterized by FTIR spectra. The results show that direct electrochemical synthesis of metal alkoxides have a high current efficiency and electrolysis yield. These alkoxides have a high purity and can be directly used as the precursor of nanosize oxides prepared by sol-gel procedure. The anodic behaviour of Ti electrode in alcohol is markedly the feature of the pitting corrosion. The passivation of Ti anode would occur in the presence of trace water.
