Hydrothermal synthesis and structural characterization of a novel organic-inorganic hybrid compound {[Cu(2, 2 '-bpy)(2)](2)-Mo8O26}

A novel organic-inorganic hybrid compound {[Cu (2, 2'-bpy)(2)](2)Mo8O26} has been hydrothermally Synthesized and structurally characterized by single-crystal X-ray diffraction. The compound crystallizes in the orthorhombic space group, Pna2(1), with a=2.4164 (5), b=1.8281 (4), c=1.1877 (2) nm, V=5.247(2) nm(3), Z=4, and final R-1=0.0331, wR(2)=0.0727. The structure consists of discrete {[Cu(2,2'-bpy)(2)](2)Mo8O26} clusters, constructed from a beta -octamolybdate subunit[Mo8O26](4-) covalently bonded to two [Cu(2,2'-bpy)(2)](2+) coordination complex cations via bridging oxo groups. In addition, the spectroscopic properties and thermal behavior of this compound have been investigated by spectroscopic techniques (UV-vis, IR, Raman and EPR spectra) and TG analysis.

仲辛基苯氧乙酸萃取Cu(Ⅱ)的性能研究

采用溶剂萃取法 ,研究了新型萃取剂——仲辛基苯氧乙酸 (CA- 12 )从盐酸介质中萃取Cu( )的性能。考察了萃取温度、平衡水相酸度、萃取剂初始浓度、氯离子浓度、铜离子浓度对萃取的影响。实验结果表明 :分配比随平衡水相酸度的增加、萃取剂初始浓度的减小而减小 ;水相中氯离子、铜离子 ( )初始浓度对分配比均有明显的影响 ;仲辛基苯氧乙酸从盐酸介质中萃取 Cu( )的过程为吸热过程 ,并计算得到其过程热 Δ H=12 .77k J/ mo

Vibronic transitions and site substitution of Eu2+ and codoped ions in KMgF3 : Eu-X (X=Ce, Cr, Gd, Cu) system

The high-resolution emission spectra of KMgF3 : Eu and KMgF3 : Eu-X(X = Ce, Cr, Gd, Cu) single crystals were measured at 300 and 77 K. The vibronic side bands of Eu2+ were characterized and an assignment of the normal mode frequencies to particular vibrations has been made. The correlation between the vibronic frequencies of Eu2+ and the site substitution of other co-dopcd ions was first found. The relationship between vibronic intensity of Eu2+ and other doped ions concentration showed that Cr3+, Gd3+ ions competed K+ sites with Eu2+ ions. Ce3+ and Eu3+ occurred the electron transference. The introduction of Cu+ made for Eu2+ substuting for K+ sites.

Hydrothermal synthesis and crystal structure of [{Cu(2,2 '-bpy)(2)}(2)Mo8O26]: a beta-octamolybdate cluster covalently bonded to two {Cu(2,2 '-bpy)(2)}(2+) coordination complexes via bridging oxo groups

An organic-inorganic hybrid solid, (Cu(2,2'-bpy)(2))(2)Mo8O26, has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Dark green crystals crystallize in the orthorhombic system, space group Pna21, a = 24.164(5), b = 18.281(4), c = 11.877(2) Angstrom, alpha = 90 degrees, beta = 90 degrees, gamma = 90 degrees, V= 5247(2) Angstrom (3), Z = 4, lambda (MoK alpha) = 0.71073 Angstrom (R(F) = 0.0331 for 5353 reflections). Data were collected on a Siemens P4 four-circle diffractometer at 293 K in the range 1.69 degrees < theta < 25.04 degrees using the omega -scan technique. The structure was solved by the direct method and refined by full-matrix least squares on F-2 using SHELXL-93. The structure of this compound consists of discrete (Cu(2,2'-bpy)(2))(2)Mo8O26 clusters, constructed from beta -octamolybdate subunits ((Mo8O26)(4-)) covalently bonded to two (Cu(2,2'-bpy)(2))(2+) coordination complexes via bridging oxo groups that connect two adjacent molybdenum sites. (C) 2001 Academic Press.

Synthesis and crystal structure of a novel amino-acid-containing polyoxometalate: K-6[Cu (Ala)(2) (H2O)(2)](2)[ CU4 (H2O)(2) (AsW9O34)(2)] center dot 16H(2)O

The novel amino-acid-containing polyoxometalate Ka(6) [Cu(Ala)(2) (H2O)(2)](2) [Cu-4 (H2O)(2) . (AsW9O34)(2)] . 16H(2)O was synthesized from the reaction of K-10[Cu-4(H2O)(2)(AsW9O34)(2)] . 20H(2)O with beta -alanine, Its structure has been determined by single crystal X-ray diffraction. It crystallizes in the triclinic space group P (1) over bar, with a=1. 196 3(2) nm, b=1. 536 5(3) nm, c=1. 591 4(3) nm, alpha =93. 97(3)degrees, beta= 110. 88(3)degrees, gamma =101. 07(3)degrees, V=2. 651 8(9) nm(3) and Z=1. Least-squares refinement of the structure leads to R and R-w factors of 0. 067 3 and 0. 162 8, respectively. An unusual structural feature of the compound is that the polyanion [Cu-4(H2O)(2) (AsW9O34)](10-) is linked with the amino-acid complex of Cu2+ by a mu -oxygen atom.

KMgF_3∶Eu,X(X=Ce,Cr,Gd,Cu)体系中Eu~(2+)振动光谱和共掺离子的格位取代

测定了一系列单掺杂 Eu2 +和双掺杂 Eu,X( X=Ce,Cr,Gd,Cu)的 KMg F3晶体在 30 0 K和 77K的高分辨发射光谱以及伴随的振动光谱 ,据此研究了 Eu2 + 在这些体系中的振动跃迁特征 ,并指认了每一振动峰所对应的正则振动模式 .首次发现了在共掺杂体系中 Eu2 +振动频率与其它掺杂离子格位取代间的相关性

Co-Cu-Al mixed oxides derived from hydrotalcite-like compound for NO reduction by CO

Various hydrotalcite based catalysts were prepared for catalytic removal of NO (NO reduction by CO). The general formula of hydrotalcite compounds (HTLc) was Co-Cu-Al-HTLc. Precalcination of these materials at 450 degrees C for NO reduction by CO, was necessary for catalytic activity. All catalysts except Co-A1 and Cu-Al have very good activity at lower temperature for NO reduction by CO. All samples were characterized by XRD and BET. The tentative reaction mechanism was also proposed.

Catalytic reduction of NO, by CO on hydrotalcites-derived mixed oxides CoAlM and MgAlM (M = Cr, Mn, Fe, Co, Ni, Cu)

Two series of mixed oxides, CoAlM and MgAlM (M = Cr, Mn, Fe, Co, Ni, Cu), were prepared by calcining their corresponding hydrotalcite-like compounds (HTLc). The ratio of Mg: Al: M (or Co: Al: hi) was 3:1:1. The catalytic activity of all samples for the reaction of NO + CO was investigated. The results showed that the activity of CoAlM was much higher than that of MgAlM. The structure and the property of redox were characterized by XRD and H-2-TPR. The results indicated that only MgO phase was observed after calcining MgAlM hydrotalcites, and the transition metals became more stable. The spinel-like phase appeared in all of CoAlM samples after the calcination, and the transition metals were changed to be more active, and easily reduced. The activities of three series of mixed oxides CoAlCu obtained from different preparation methods, different ratio of Co:Al: Cu and at different calcination temperatures, were studied in detail for proposing the mechanism of reaction. The ability of adsorption of NO and CO were investigated respectively for supporting the mechanism.

Electrochemical behavior of a series of undecatungstozincates monosubstituted by first-row transition metals, ZnW11M(H2O)O-39(n-) (M = Cr, Mn, Fe, Co, Ni, Cu or Zn)

The electrochemical behavior of a series of undecatungstozincates monosubstituted by first-row transition metals, ZnW11M(H2O)O-39(n-) (M=Cr, Mn, Fe, Co, Ni, Cu or Zn), was investigated systematically and comparably in aqueous solutions by electrochemical and in situ UV-visible-near-IR spectroelectrochemical methods. These compounds exhibit not only successive reduction processes of the addenda atoms (W) in a negative potential range, but some of them also involve redox reactions originating from the substituted transition metals (M) such as the reduction of Fe-III and Cu-II at less negative potentials and the oxidation of Mn-II at a more positive potential. Some interesting results and phenomena, especially of the transition metals, were found for the first time. Moreover, possible reaction mechanisms are proposed based on the experimental results.

Valences of Cu in Y1-xCaxBa2Cu3O6+y

The valences of Cu in Y1-xGaxBa2Cu3O6+y have been investigated by using complex chemical bond theory The results for the valences of Cu(1) and Cu(2) in the calculation suggest that the holes introduced by calcium substitution only reside in CuO2 planes, and there is a competition mechanism for the hole density in CuO2 planes between Ca doping and oxygen depletion. These conclusions are satisfactorily in agreement with experiments.

Semiempirical study on the valences of Cu and bond covalency in Y1-xCaxBa2Cu3O6+y

The valences of Cu and bond covalencies in Y1-xCaxBa2Cu3O6+y, have been investigated using complex chemical bond theory, This theory is the generalization of Phillips, Van Vechten, Levine, and Tanaka's scheme. The results indicate that the valences of Cu(1) and Cu(2) in our calculation agree well with those obtained by the bond valence sum method. The valences of Cu(1) and Cu(2) in our calculation also suggest that the holes introduced by Ca substitution only reside in CuO2 planes and there is a competing mechanism for the hole density in CuO2 planes between,Ca doping and oxygen depletion. These conclusions are in satisfactory agreement with experiments. The calculated ordering of covalencies is Cu(1)-O(4)>Cu(1)-O(1)>Cu(2)-O(2,3)>Cu(2)-O(1)>Ca-O>Y-O similar to Ba-O, regardless of the Ca doping level and oxygen content. [S0163-1829(98)03325-6].

Layered La-Ba-Cu mixed oxides with perovskite structure as catalyst for NO reduction by CO

The mixed oxides, including LaBa2Cu3O7, LaBaCu2O5, La4BaCu5O12 with perovskite structure, were prepared. The catalysts were characterized by means of chemical analysis, XRD, H-2-TPR. It was found that their structures were layered ABO(3) perovskite structure and they were the active catalysts for the NO reduction by CO. The existence of Cu3+ is an important factor to give the catalysts a high activity for the NO reduction by CO.

Studies on the elimination of NO over the La-Ba-Cu mixed oxide catalysts with perovskite structure

The mixed oxides, including YBa2Cu3O7, LaBa2Cu3O7, LaBaCu2O5, La2BaCu3O7, La4BaCu5O12 with perovskite structure, were prepared. The catalysts were characterized by means of chemical analysis, XRD, TPD and TPR method. It was found that they were the active catalysts for the NO decomposition and NO reduction by CO. The existance of Cu3+ is an important factor to give the catalysts a high activity for the NO reduction by CO.