Kondensierte Al6‐Ringe in den Subiodiden La3Al2I2 und La2Al2I

Condensed Al₆ Rings in the Subiodides La₃Al₂I₂ and La₂Al₂I The subiodides La₃Al₂I₂ and La₂Al₂I are reported. The compounds were prepared from stoichiometric mixtures of lanthanum, aluminium, and LaI₃ under Ar atmosphere in sealed Ta ampoules at 920–950 °C and 980–1000 °C, respectively. La₃Al₂I₂ crystallizes in space group C2/m with a = 19.73(2) Å, b = 4.318(1) Å, c = 12.348(9) Å and β = 121.49(3)°, La₂Al₂I in P6₃/mmc with a = 4.3718(8) Å and c = 17.605(2) Å (isotypic with Gd₂Fe₂I). Both structures are characterized by sheets of trigonal prisms formed by the La atoms centered by aluminium, the latter being arranged in Al₆ rings. These rings are connected to chains in La₃Al₂I₂ (d_{Al(2)–Al(2)} = 2.550(4) Å and 2.615(2) Å, respectively) and layers (d_Al–Al = 2.533(1) Å) in La₂Al₂I. Both compounds are metallic conductors. The electronic structure of both compounds is discussed based on band structure calculations.     

Synthesis and transformations of metallacycles. 26. Cp2ZrCl2-Catalyzed cycloalumination of substituted allenes with Et3Al

Catalytic cycloalumination of 1-alkyl(phenyl)allenes with triethylaluminum (5 mol.% of Cp₂ZrCl₂ as the catalyst, 20 °C, 4 h, hexane) afforded methylene- and alkyl(benzyl)idene-substituted alumacyclopentanes.     

某些Al2Cu型和CrSi2型化合物的能带结构研究

Al2Cu型和CrSi2型固相过渡金属原子簇化合物M2B(M=Mo, W),M2Ni(M=Zr, Hf)和MGe2(M=Nb, Ta)在低温下出现超导行为。本文采用扩展的Huckel近似下的紧束缚能带方法, 计算了它们的能带结构, 给出了其能带、态密度与晶体轨道重叠布居, 讨论了晶体中化学键强度与超导转变温度的关系。     

Intercalation of 2-Naphthol-3,6-disulfonate, 9,10-Anthraquinone-2,6-disulfonate, and 9,10-Anthraquinone-2-sulfonate Anions into Zn–Al Layered Double Hydroxide

The intercalates of 9,10-anthraquinone-2,6-disulfonate, 9,10-anthraquinone-2-sulfonate, and 2-naphthol-3,6-disulfonate anions were prepared by heating [Zn_0.67Al_0.33(OH)₂](CO₃)_0.165 · 0.5H₂O with a solution of corresponding acid in an open reaction vessel. The intercalates were characterized by chemical and thermal analysis, X-ray powder diffraction and UV-vis spectroscopy. Thermal behavior of the intercalates prepared was followed by in situ X-ray diffraction. Dehydration was reversible for all three intercalates. If the samples dehydrated at 400 °C reacted with water, brucite-like layers of the host were reconstructed. Received in final form: 14 January 2005     

Co-Mg/Al类水滑石衍生复合氧化物上N2O催化分解的研究

恒定二价与三价阳离子比为3((nCo+nMg)/nAl=3), 采用共沉淀法制备不同Co含量的系列类水滑石前驱物CoxMg3-xAl-HT(x=0, 0.5, 1, 1.5, 2, 2.5, 3), 经焙烧得到其衍生复合氧化物催化剂CoxMg3-xAlO. 采用XRD、BET、TG-DSC和TPR等表征手段考察了Co含量对材料前驱物及其衍生复合氧化物组成和结构等方面的影响, 研究了系列CoxMg3-xAlO催化剂的催化N2O分解性能; 同时探讨了反应条件, 如N2O浓度、空速、O2和H2O等因素对催化剂活性的影响. 结果表明, 所有前驱物材料均能形成完整的层状水滑石结构；经高温焙烧后形成了以Co-Al尖晶石为主相的复合氧化物, 且Co掺杂有助于尖晶石相的生成； Co含量对材料的热稳定性、比表面、可还原性和催化分解活性有显著的影响；含Co复合氧化物催化材料存在两个还原峰, 还原过程为Co3+→Co2+→Co；Mg有助于提高催化剂的热稳定性；随着Co含量增加, 催化剂比表面下降, 但比表面不是影响催化剂活性的主要因素； 500 ℃焙烧后的Co2.5Mg0.5AlO催化剂具有较好的N2O催化分解活性；提高前驱物的焙烧温度导致催化剂的活性下降；N2O浓度、空速及O2对催化剂活性的影响较小, 而H2O则对催化剂的活性有较大的影响.     

裂解汽油中噻吩硫在Co-Mo/Al2O3上的催化加氢宏观动力学

采用绝热管式固定床积分反应器，在2.5MPa~3.9MPa、513K~655K、氢/裂解汽油摩尔比1.8~3.5和裂解汽油中噻吩、单甲基噻吩和双甲基噻吩质量分数为838×10－6、137×10－6~723×10－6和192×10－6~723×10－6下，对Co-Mo/Al2O3催化剂上裂解汽油催化加氢脱硫的宏观动力学进行了研究。以Powell优化法和Merson迭代法对动力学实验数据进行非线性参数估值，建立了良好吻合实验数据的、裂解汽油催化加氢脱硫的幂函数型宏观动力学模型。噻吩、单甲基噻吩和双甲基噻吩的反应级数分别为0.721、0.735和0.87，对应的加氢反应宏观活化能依次为70.0kJ·mol－1、67.9kJ·mol－1和59.9kJ·mol－1。各噻吩基硫的转化率均随反应压力的提高而增加，3.5MPa以上时，增加的趋势减缓；反应温度的提高有利于噻吩基硫转化率的增加；593K以上时，各硫化物的转化率随温度的增加呈现线性增加的趋势。     

Die Reaktion des [(Me3Si)2CH]2Al?CH2?Al [CH(SiMe3)2]2 mit LiCH(PMe2)2; Bildung eines fünfgliedrigen Al2C2P-Heterozyklus

The Reaction of [(Me₃Si)₂CH]₂Al? CH₂? Al [CH(SiMe₃)₂]₂ with LiCH(PMe₂)₂; Formation of a Five-membered Al₂C₂P Heterocycle The recently synthesized methylene bridged dialuminium compound [(Me₃Si)₂CH]₂Al? CH₂? Al [CH(SiMe₃)₂]₂ 3 reacts with one equivalent of LiCH(PMe₂)₂ in the presence of TMEDA to give an adduct with one aluminium atom coordinated by the carbanionic carbon atom and the second one coordinated by one phosphorus atom. A five-membered heterocycle 5 is formed, which was characterized by a crystal structure determination showing a strongly bent ring with the phosphorus atom located above the plane of the four remaining atoms (Al₂C₂). 5 is unstable in ethereal solution decomposing under ether cleavage to the educt 3 and the diphosphinomethane derivative CH₂(PMe₂)₂.     

Pentacarba-arachno-tridecaalane (AlMe)8(CCH2Ph)5H with an Al8C5 Skeleton—The First Polyhedral Carbaalane

Hydroalumination of an aluminum alkynide led to the formation of a polyhedral carbaalane as the first example of a new class of aluminum derivatives analogous to carbaboranes. A pentacarbatridecaalane was obtained, which has an Al₈C₅ skeleton and which, owing to the number of electrons in the cluster, belongs to the arachno-type group of compounds (see structure).     

(η5-C5H5)2TiCl2- hydroalumination of α-olefins with Et3Alhydroalumination of α-olefins with Et3Al

A preparative method for the synthesis of (alkyl)diethylalanes from α-olefins and Et₃Al catalyzed by Cp₂TiCl₂ (Cp=η⁵-C₅H₅)is proposed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 712–715, April, 1998.     

Microwave-assisted reconstruction of Ni,Al hydrotalcite-like compounds

The microwave-assisted reconstruction of Ni,Al hydrotalcite-like compounds (HTlcs) with Ni/Al molar ratios 2/1 and 3/1 has been studied. Mixed oxides obtained after calcination of the HTlcs are immersed in three different solutions containing carbonate, distilled water and an aqueous NH₃ solution, and then heated at different temperatures for increasing periods of time under microwave radiation. The evolution of the structure during the treatment is followed by powder X-ray diffraction, FT-IR and vis-UV spectroscopies and SEM and TEM microscopies. Full recovery of the original layered structure is achieved in short periods of time for the 2/1 samples when the calcined HTlcs are rehydrated in the Na₂CO₃ solution, but more drastic conditions are necessary for the 3/1 samples and the reconstruction seems not to be complete. Finally, only a partial reconstruction is observed in distilled water or NH₃ aqueous solution.