Synthese und thermische Eigenschaften von molekularen Clusterverbindungen zusammengesetzt aus Elementen der Gruppen 11‐13‐16

Syntheses and Thermal Properties of Cluster Molecules, formed from Groups 11‐13‐16 Elements In the presence of PPh₃, CuX (X = Cl, CH₃COO) or AgOC(O)C₆H₅ and GaCl₃ react in THF with S(SiMe₃)₂ or Se(SiMe₃)₂ to yield [Cu₆Ga₈Cl₄S₁₃(PPh₃)₆] ( 1 ), [Cu₆Ga₈Cl₄Se₁₃(PPh₃)₆] ( 2 ), [Ag₆Ga₈Cl₄S₁₃(PPh₃)₆] ( 4 ) and [Ag₆Ga₈Cl₄Se₁₃(PPh₃)₆] ( 5 ). The use of PⁿPr₂Ph instead of PPh₃ and subsequent layering with n‐hexane leads to the formation of the cluster [Cu₆Ga₈Cl₄Se₁₃(PⁿPr₂Ph)₁₂] ( 3a , 3b ). Reaction of CuCl, GaCl₃ and PⁿPr₃ with Se(SiMe₃)₂ in THF results in the crystallisation of the ionic cluster (HPⁿPr₃)₂[Cu₂Ga₄Cl₄Se₆(PⁿPr₃)₄] ( 6 ). The structures of 1 — 6 were determined by X‐ray single crystal structure analysis. Thermogravimetric measurements of the cluster molecules and powder diffraction patterns of the remaining powders reveal the potential use of them as single source precursor compounds for the synthesis of the related ternary solid state materials.     

Comparison ofn-decane hydroconversion with Pt/SAPO-5 and Pt/SAPO-11 catalysts

The product distributions from bifunctional conversion ofn-decane over Pt/SAPO-5 and Pt/SAPO-11 catalysts are compared in detail. Selectivities in decane reaction vary largely with the catalyst employed: Pt/SAPO-11 produces high yields of feed isomers, whereas Pt/SAPO-5 gives high yields of cracked products and only under mild reaction conditions are isodecanes the main products obtained. These selectivities seem to be determined by the structure of the catalyst.     

Darstellung und spektroskopische Charakterisierung von Carboxylatododecaboraten

Preparation and Spectroscopic Characterization of Carboxylatododecaborates The tetrabutylammonium salt (TBA)₂[B₁₂H₁₂]^2? reacts with formic, acetic, cyanoacetic, phenylacetic, propionic, butyric, and thioacetic acid at temperatures between 80 and 150°C forming the carboxylatododecaborates [(RC(O)O)_n? B₁₂H_{12? n}]^2?, n = 1, 2, [CH₃C(O)S? B₁₂H₁₁]^2?. The isolation of the pure compounds is achieved by ion exchange chromatography on diethylaminoethyl cellulose. In case of the dicarboxylatododecaborates beside the 1,7-isomer predominantly the 1,2-isomer, while 1,2-[(OH)C₆H₅CH₂C(O)O? B₁₂H₁₀]^2? is formed exclusively. The alcaline hydrolysis of [RC(O)O? B₁₂H₁₁]^2? and 1,2-[(OH)C₆H₅CH₂C(O)O? B₁₂H₁₀]^2? results in [(OH)? B₁₂H₁₁]^2? and 1,2-[(OH)₂? B₁₂H₁₀]^2?. All compounds are characterized by their ¹¹B-nmr, ¹³C-nmr and IR spectra. The ¹¹B-nmr signals are assigned by a sheme allowing to establish expected spectra.     

源内裂解液相色谱-质谱鉴别人参皂甙砒和拟人参皂甙F11

研究了利用源内碰撞诱导解离（in-source collision—induced dissociation）的高效液相色谱-大气压化学电离质谱（HPLC—APCI／MS）获取人参和西洋参的化学标志物——人参皂甙Rf和拟人参皂甙F11的特征结构信息及鉴别人参和西洋参的方法。在乙腈-水梯度洗脱反相液相色谱及源内碰撞诱导解离条件下，能获得人参皂甙Rf和拟人参皂甙F11的母核离子及去糖基离子的源内碰撞诱导解离谱，从其差别能清楚区分这对同分异构体。本方法对人参皂甙Rf和拟人参皂甙F11的检出限能达到10^-7g柱上样量，简单、快速，单次质谱实验就能鉴别人参和西洋参。     

硝酸钬水合物热分解及配位性质的研究

文献报道了Ho(NO_3)_3·5H_2O和Ho(NO_3)_3·(?)H_2O的热分解行为,但Ho(NO_3)_3·5H_2O脱水机理不清,Ho(NO_3)_3·4H_2O按文献[1]不能制出。六水、三水合物的热分解及与DMF的配位作用未见报道。     

CoAPO-11分子筛的合成、表征和催化性能： 1-己烯异构化反应

水热法合成了钴取代磷铝酸盐分子筛CoAPO-11，并采用了X射线衍射、扫描电子显微镜、红外光谱、紫外可见光谱以及氮气吸脱附等表征手段对合成的样品进行表征，并在合成的分子筛上进行1-己烯异构化反应评价，并考查了温度和空速对反应的影响。结果表明，在反应温度300℃及空速为2.4h－1CoAPO-11分子筛对1-己烯异构化反应具有较好的催化性能。     

BaCe0.8Ho0.2O3-a陶瓷的性质与应用

Ceramic BaCe0.8Ho0.2O3-α with orthorhombic perovskite structure was prepared by conventional solid state reaction, and its conductivity and ionic transport number were measured by ac impedance spectroscopy and gas concentration cell methods in the temperature range of 600-1000 ℃ in wet hydrogen and wet air, respectively. Using the ceramics as solid electrolyte and porous platinum as electrodes, the hydrogen-air fuel cell was constructed, and the cell performance at temperature from 600-1000 ℃ was examined. The results indicate that the specimen was a pure protonic conductor with the protonic transport number of 1 at temperature from 600-900 ℃ in wet hydrogen, a mixed conductor of proton and electron with the protonic transport number of 0.99 at 1000 ℃. The electronic conduction could be neglected in this case, thus the total conductivity in wet hydrogen was approximately regarded as protonic conductivity. In wet air, the specimen was a mixed conductor of proton, oxide ion and electron hole. The protonic transport numbers were 0.01-0.09, and the oxide-ionic transport numbers were 0.27-0.32. The oxide ionic conductivity was increased with the increase of temperature, but the protonic conductivity displayed a maximum at 900 ℃, due to the combined increase in mobility and depletion of the carriers. The fuel cell could work stably. At 1000 ℃, the maximum short-circuit current density and power output density were 346 mA/cm^2 and 80 mW/cm^2, respectively.     

CexTi1-xO2复合氧化物的结构及负载CuO对NO还原性能研究

采用共沉淀法制备了不同摩尔比(x=0,0.1,0.2～0.9,1.0)的CexTi1-xO2复合氧化物,考察了CuO/CexTi1-xO2对NO+CO反应的活性,并用BET,TPR和XRD等技术对各试样进行了表征。结果表明,试样的结构和还原特性随焙烧温度变化而变化。XRD检测表明,x值从0.1增加到0.5时,650℃焙烧的试样已形成了CeTi2O6物相,且主要以无定形状态存在;试样经800℃焙烧后晶化完全;x>0.6时,一些TiO2已经进入了CeO2晶格,形成了Ce Ti固溶体。催化剂活性评价表明CuO/CexTi1-xO2(650℃)对NO+CO反应具有较好的活性,其活性随x值变化而变化。TPR及XRD结果表明CuO与CeTi2O6之间存在很强的相互作用,CeTi2O6物相的形成使CuO的还原峰温由380℃提前到200℃,而CuO的存在又促进CeTi2O6的还原峰温从600℃提前至200～300℃。     

Cyclotomic units over finite fields

Let ζ be a primitivesp-th root of unity for a primep>2, and consider the group Ω(ζ) of cyclotomic units in the ringR(ζ)=ℒ[ζ+ζ^-1]. This paper deals with the image of Ω(ζ) in the unit group ofR(ζ)/qR(ζ), whereq is a prime ≠p. In particular, it obtains criteria for this image to be essentially everything, and a lower bound on the density of primesp (withq fixed) for which it cannot be. These results have a direct bearing on previous work about units in integral group rings for cyclic groups of orderpq. Work supported in part by an operating grant from NSERC (Canada).     

Frobenius-Perron operators and approximation of invariant measures for set-valued dynamical systems

A set-valued dynamical systemF on a Borel spaceX induces a set-valued operatorF onM(X) — the set of probability measures onX. We define arepresentation ofF, each of which induces an explicitly defined selection ofF; and use this to extend the notions of invariant measure and Frobenius-Perron operators to set-valued maps. We also extend a method ofS. Ulam to Markov finite approximations of invariant measures to the set-valued case and show how this leads to the approximation ofT-invariant measures for transformations , whereT corresponds to the closure of the graph of .