1,2-双(四甲基环戊二烯基)四甲基二硅烷与六碳基钼的反应

1,2-双(四甲基环戊二烯基)四甲基二硅烷与正丁基锂作用生成(四甲基二硅撑)双(四甲基环戊二烯基负离子盐),后者随即与六碳基钼反应形成1,1'-(四甲基二硅撑)双(四甲基环戊二烯基铝负离子盐)-(Me₂SiSiMe₂)[Me₄CpMo(CO)₃-Li⁺]₂(I),I与冰醋酸作用,随即分别与CCl₄,NBS及I₂反应,生成相应的铝卤化合物(Me₂SiSiMe₂)[Me₄CpMo(CO)₃X]₂[X=Cl(1),Br(2),I(3)].I与CH₃I反应,在钼原子上发生烃基化,得到产物(Me₂SiSiMe₂)[Me₄CpMo(CO)₃Me]₂(4);I与单质I₂直接反应,生成脱硅桥产物Me₄Cp(CO)>₃I(5).经元素分析、IR及¹HNMR表征了化合物1-5的结构。     

手性联萘酚锂盐催化下三甲基硅氰与芳香醛的对映选择加成反应研究

光学活性芳香氰醇及其衍生物是合成一些具有重要生理活民生天然产物的关键中间体。氰基醇的对映选择合成主要是利用由光学活性手性配体与甲价钛形成的配合物为手性催化剂,催化醛与氢氰酸或三甲基硅氰（TMSCN）的加成,由于手性联萘酚（BINOL）在很多反应中表现出优异的立体选择催化活性,故试图用其催化醛与氢氰酸或TMSCN的加成,但对映选择性不理想,我们用BINOL与正丁基锂作用生成的盐催化芳香醛与TMSCN的对映选择加成,取得了较好的结果。     

硼化合物研究(Ⅲ)——B10H102-、B12H122-以及B3H8-阴离子的二茂铁季铵盐的合成

本文通过B_nH_n^2-(n=10,12)及B₃H₈^-盐分别与C₅H₅FeC₅H₄CH₂N(R)Me₂Cl和Fe(C₅H₄CH₂N(R)Me₂Cl)₂(R=CH₃-,C₂H₅-,n-C₃H₇-,CH₂=CH-CH₂-和CH≡C-CH₂-)在水溶液中进行反应,合成了相应的三十个新的硼烷阴离子衍生物,这些化合物对水稳定性好,B₁₀H₁₀^2-及B₁₂H₁₂^2-衍生物对热、酸、碱和氧化剂均很稳定。研究了反应物之间的用量比例对反应产物的影响。实验结果表明,不论反应物之间的克分子比如何变化,只能得到相应的一种产物(产率90-98％)。     

硅桥连双(三甲硅基环戊二烯基)钛化合物的合成及脱硅基反应

硅桥连双(三甲硅基环戊二烯基)双锂盐与TiCl₄·2THF反应,生成相应的钛化合物[E(C₅H₃SiMe₃)₂]TiCl₂[E=Me₂SiSiMe₂(3),Me₂SiOSiMe₂(5)],同时还分离到了脱一个三甲硅基的产物[E(C₅H₄)(C₅H₃SiMe₃)]TiCl₂[E=Me₂SiSiMe₂(4),Me₂SiOSiMe₂(6)].其中四甲基二硅氧桥连配体更容易发生这种脱硅基反应.通过元素分析、MS和¹HNMR谱表征了化合物3-6的分子结构.     

中间体C60(CH3)-和产物C60(CH3)2的结构及产物

用INDO系列方法对C₆₀^2-与CH₃反应的中间体C₆₀(CH₃)^-进行理论研究,得到具有Cs对称性的构型。结果表明,CH₃加成到C₁₅上,将使与其相邻的双键碳(C₃₀)的电荷密度和自旋密度达极大值,故加成反应部位在C₃₀处;另外,C₁₅的对位C₁₂(或C₂₇)也较其它部位易于反应,且有两个反应场所,因而产物C₆₀(CH₃)₂可能为六元环上的1,2-加成和1,4-加成两种异构体的混合物。同时对两种加成产物的结构和电子光谱进行了理论研究,指认其电子跃迁,并讨论了其光谱红移的原因。     

二乙基锌促进CO2的硅氢化反应以及CO2为C1合成子的有机胺甲酰化或脲化反应

CO₂的固定和转化具有重要研究意义,特别是采用廉价且良好生物相容性的金属催化剂将其转化为有用的有机化合物.本工作报道采用商品化ZnEt₂（1.0 mol%）可促进CO₂的硅氢化反应生成甲氧基硅醚,以及CO₂为C1合成子的有机胺甲酰化或脲化反应生成酰胺或脲类化合物.在1.0 mol% ZnEt₂存在下,CO₂和（EtO）₃SiH发生硅氢化反应,一锅选择性还原为甲氧基硅醚（CH₃OSi（OEt）₃）.考察了反应条件的影响,在1.0 MPa CO₂起始压力下,90℃反应7 h,甲氧基硅醚的产率达到约90%.当上述反应体系中存在有机胺时,则发生了CO₂为C1合成子的的有机胺甲酰化或脲化反应.当采用二级有机胺为底物时,反应生成酰胺类产物;当一级有机胺为底物时,反应主要生成脲类产物.考察了反应底物取代基的影响,含脂肪基和芳香基的二级有机胺均可发生甲酰化反应,芳香基的对位含给电子取代基时明显有利于该甲酰化反应.含脂肪基和芳香基的一级有机胺均可发生脲化反应,芳香基对位取代基的电子性质对脲化反应的影响规律不如在甲酰化反应中的明显.     

乙醇在Co(111)表面脱氢反应机理的第一性原理研究

采用密度泛函理论和周期平板模型相结合的方法针对Co（111）表面上乙醇脱氢反应的反应机理进行了细致的研究,同时,对反应过程中涉及到的各个物种在表面上不同吸附位（顶位（top）,桥位（bridge）,三重空穴位（fcc和hcp））的吸附模型进行了结构优化以及相关能量的计算,确定了各物种的最佳吸附位点.研究结果表明,CH₃CH₂OH在Co（111）表面的脱氢反应可具体描述为三条反应路径：反应路径I为CH₃CH₂OH逐步脱氢经由中间体CH₃CHO,最终生成CH₄和CO的反应;反应路径Ⅱ为CH₃CH₂OH脱氢产生的CH₃CH₂O基和CH₃CHO相互作用通过CH₃COOH分子最终生成CH₄和CO₂的反应;反应路径Ⅲ为CH₃CH₂O基和CH₃CO基作用生成CH₃COOC₂H₅的过程,其中,反应路径I为最优路径（CH₃CH₂OH→CH₃CH₂O→CH₃CHO→CH₃CO→CH₃+CO→CH₂→CH→CH₄+CO+C+H）,该反应路径中的CH₃CH₂O基脱氢生成CH₃CHO为速控步骤,反应能垒为1.61 eV.     

定向合成高效捕获CO2的新型多孔芳香材料

通过简单的离子热法,以四（4-氰基联苯基）硅烷作为四面体基块,将其与无水氯化锌在充满氩气气氛的手套箱中充分研磨后密封,分别以400和550 ℃的反应温度合成了新型多孔芳香骨架材料（PAF-51）,得到PAF-51-1（400 ℃条件下）与PAF-51-2（550 ℃条件下）的比表面积分别为720和557 m²·g^-1 （BET）.与CH₄和N₂对比,该材料对CO₂具有极好的选择性吸附能力. 273 K条件下,CO₂/N₂分离指数最高可达52.2,CO₂/CH₄分离指数也达到10.3,这一性质极有可能使得PAF-51成为捕获CO₂理想材料,并对再生能源具有潜在的应用.     

Ag-ZSM-5催化剂上CH4选择催化还原NOx的研究

摘要研究Ag-ZSM-5催化剂上CH₄选择性催化还原NO_x的反应性能,采用TPD和TPSR技术研究NO和O₂共吸附于Ag-ZSM-5催化剂表面形成的吸附物种及其和CH₄之间的反应。结果表明,Ag-ZSM-5催化剂上CH₄选择性还原NO_x活性和选择性较高。NO和O₂共吸附在Ag-ZSM-5催化剂上形成的NO₃(s)吸附物种能被CH₄还原生成N₂.在NO₃(s)和O₂共存的体系中,CH₄能优先并选择性还原NO₃(s)生成N₂.     

(p-CH3OC6H4)2TeO存在下M2(CO)10(M=Mn,Re)的CO取代反应动力学研究

测定了(p-CH₃OC₆H₄)₂TeO存在下M₂(CO)₁₀(M=Mn,Re)的CO取代反应速率及活化参数。其表观速率常数分别与M₂(CO)₁₀和(p-CH₃OC₆H₄)₂TeO的浓度的一次方成正比。本文所建议的缔合机理与前人用(CH₃)₃NO作氧原子转移试剂的相应反应所提出的机理相似。讨论了在(CH₃)₃NO和(p-CH₃OC₆H₄)₂TeO存在下影响M₂(CO)₁₀的CO取代反应速率的因素。     

镍硫配合物(Me3C+)2Ni(SCH2CH2S)2的合成及结构表征

以NiCl2,Bu4NBr,HSCH2CH2SH为原料合成了配合物(Me3C^ )2Ni(SCH2CH2S)2,其结构经元素分析、IR,UV和^1H NMR确证,X-射线四圆衍射仪测其晶胞参数为：a=0.9127(1)nm,b=1．2424(0)nm,c=1．3906(2),v=1．57685(2)nm^3,z=4,晶体属正交晶系。晶体结构经块状矩阵最小二乘法修正后,最终偏离因子R=0．089。     

Die Kristall- und Molekülstrukturen von (Me2SiNCN)4 (1) und Me3SiNCNSiMe3 (2)

Crystal and Molecular Structures of (Me₂SiNCN)₄ (1) and Me₃SiNCNSiMe₃ (2) Synthesis, spectroscopic characterization (NMR, IR, Raman and MS) and crystal structure of the novel compound 1 are described. The molecules form almost planar 16 membered rings with four SiMe₂-groups connected to four NCN groups. The corresponding compound 2 exhibits a phase transition from the HT phase 2a to the LT phase 2b at 131 K. Consecutive X-ray structure determinations of the molecular structures of both modifications were performed on a crystal, grown in situ on the diffractometer at 231 K.     

Thermal decomposition of Me3SnO2PCl2, Me2Sn(O2PCl2)2 and Ph3SnO2PCl2

TG and DTA studies on Me₃SnO₂PCl₂, Me₂Sn(O₂PCl₂)₂ and Ph₃SnO₂PCl₂ were carried out under dynamic argon atmosphere. The results show that the decomposition proceeds in different stages leading to the formation of Sn₃(PO₄)₂ as a stable product. This compound was characterized by IR spectroscopy. Decomposition schemes involving reductive elimination reactions were proposed.     

Highly Efficient Syntheses of β-Cyanoketones via Conjugate Addition of Me3SiCN to Aromatic Enones

An efficient 1,4‐addition of Me₃SiCN to aromatic enones has been achieved with excellent yields (91% –99%) using CsF (1 mol%) as the catalyst and H₂O (4 equiv.) as the additive in refluxing dioxane within 7 h. The perfect regioselectivity is proposed accounting from H₂O‐facilitated reversion of the 1,2‐adduct in the presence of CsF and subsequent irreversible 1,4‐addition reaction.     

Komplexchemie P-reicher Phosphane und Silylphosphane. VII. Carbonylkomplexe des Heptaphosphans(3) iPr2(Me3Si)P7

Transition Metal Complexes of P-rich Phosphanes and Silylphosphanes. VII Carbonyl Complexes of the Heptaphosphane(3) iPr₂(Me₃Si)P₇ From the reaction of iPr₂(Me₃Si)P₇ 1 with one equivalent of Cr(CO)₅THF the yellow products iPr₂(H)P₇[Cr(CO)₅] 2 and iPr₂(Me₃Si)P₇[Cr(CO)₅] 3 were isolated by column chromatography on silicagel. The P? H group in 2 results from a cleavage of the P? SiMe₃ bond during chromatography. The Cr(CO)₅ group in 2 is linked to an iPr? P^e atom, in 3 to the Me₃Si? P^e atom of the P₇ skeleton. The substituents do not force the formation of a single isomer; nevertheless 3 ist considerably favoured as compared to 2 . From the reaction of 1 with 2 equivalents of Cr(CO)₅THF the yellow iPr₂(H)P₇[Cr(CO)₅]₂ 4 was isolated bearing one Cr(CO)₅ group at an iPr? P^e atom, the other one at a P^b atom of the P₇ skeleton. Compound 3 yields with Cr(CO)₄NBD the red iPr₂(Me₃Si)P₇[Cr(CO)₅][Cr(CO)₄] 5 . Three isomers of 5 appear. Two P^e atoms of 5 are bridged by the Cr(CO)₄ group, the third P^e atom is linked to the Cr(CO)₅ ligand. iPr₂(H)P₇[Fe(CO)₄] was isolated from the reaction of 1 with Fe₂(CO)₉. ³¹P NMR and MS data are reported.     

Zur Bildung und Struktur der Phosphinophosphiniden-phosphorane tBu2P?PP(Me)tBu2 1, tBu(Me3Si)P?PP(Me)tBu2 2 und tBu2P?PP(Br)tBu2 3

Synthesis and Structure of Phosphinophosphinidene-phosphoranes tBu₂P? P?P(Me)tBu₂ 1, tBu(Me₃Si)P? P?P(Me)tBu₂ 2, and tBu₂P? P?P(Br)tBu₂ 3 A new method for the synthesis of 1 and 2 (Formulae see ?Inhaltsübersicht”?) is reported based on the reaction of 5 with substitution reagents (Me₂SO₄ or CH₃Cl). The results of the X-ray structure determination of 1 and 2 are given and compared with those of 3 . While in 3 one P? P distance corresponds to a double bond and the other P? P distance to a single bond (difference 12.5 pm) the differences of the P? P distances in 1 and 2 are much smaller: 5.28 pm in 1 , 4.68 pm in 2 . Both 1 and 2 crystallize monoclinic in the space group P2₁/n (Z = 4). 2 additionally contains two disordered molecules of the solvent pentane in the unit cell. Parameters of 1 : a = 884.32(8) pm, b = 1 924.67(25) pm, c = 1 277.07(13) pm, β = 100.816(8)°, and of 2 : a = 1 101.93(12) pm, b = 1 712.46(18) pm, c = 1 395.81(12) pm, β = 111.159(7)°, all data collected at 143 K. The skeleton of the three P atoms is bent (PPP angle 100.95° for 1 , 100.29° for 2 and 105.77° for 3 ). Ab initio SCF calculations are used to discuss the bonding situation in the molecular skeleton of the three P atoms of 1 and 3 . The results show a significant contribution of the ionic structure R₂P? P(^?)? P(⁺)(X)R₂. The structure with (partially) charged P atoms is stabilized by bulky polarizable groups R (as tBu) as compared to the fully covalent structure R₂P? P(X)? PR₂.     

Der thermische Zerfall des tBu2P?PP(Me)tBu2

The Thermal Decomposition of ^tBu₂P? P?P(Me)^tBu₂ The thermal decomposition of ^tBu₂P? P?P(Me)^tBu₂ 2 in C₆H₆ at 20°C is detectable after 10 h; ^tBu₂PMe, (^tBu₂P)₂PH and small amounts of the cyclotetraphosphanes P₄(P^tBu₂)₄ and P₄(P^tBu₂)₂ are formed. At 70°C (14 h) 83% of 2 are decomposed, and even 96% after 74 h. The main products are ^tBu₂PMe (68%) and P₄(P^tBu₂)₄ (20%). With 2,3-dimethyl-1,3-butadiene as a trapping reagent ^tBu₂PMe (62%) is still the main product, however, P₄(P^tBu₂)₄ is no longer found, but 1,2-bis(di-tert-butylphosphino)-4,5-dimethyl-1,2-diphosphacyclohexene-4 (22%) is formed instead. Also with cyclohexene ^tBu₂PMe (78%) remains the major product besides P₄(P^tBu₂)₄ (9%) and small amounts of the trapping product 7-di-tert-butylphosphino-7-phosphabicyclo[4.1.0]heptane. Thus, the thermal decomposition of 2 at 70°C proceeds very similar to that of ^tBu₂P? P?P(Br)^tBu₂ at ?30°C and starts yielding and the phosphinophosphinidene ^tBu₂P? P. In CH₂Cl₂ the decomposition of 2 includes the chlorination of the ylidic molecule.     

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.     

Addition of Me3SiCN to trifluoromethyl derivates of N‐(pyridylmethylidene) anilines catalyzed by Lewis acids

A series of novel Shiff bases (1a–h) was synthesized by condensation of pyridinecarboxaldehydes (1–4) with 3‐ and 4‐trifluoromethylanilines (5, 6) in the presence of molecular sieves (4 Å). It was found that AlCl₃ and AlBr₃ catalyzed the addition of Me₃SiCN to the C?N bond of the imines obtained, whereas the other Lewis acids studied (YCl₃, LaCl₃, ZnI₂) were not active. The reactivity of the imines in the title reaction, on the whole, correlated with their basicity. Besides the addition giving the expected α‐amino nitriles (2a,b,d–f,h), an unusual reaction leading to unsaturated nitriles (3a–h) was observed. The structures of saturated and unsaturated products 2d and 3c were determined by X‐ray diffraction. Copyright © 2001 John Wiley & Sons, Ltd.     

Nouvelles syntheses de Me2SiCl2 et Me3SiCl

Partial reduction of MeSiCl₃ and Me₂SiCl₂ using CaH₂ or (TiH₂)_n at high temperature (300°C) leads to MeSiHCl₂ and Me₂SiHCl, respectively, in good yields but in low proportion. In the presence of AlCl₃ as catalyst the reaction affords Me₂SiCl₂ and Me₃SiCl, in yields higher than those previously observed in the absence of a reducing agent. These redistribution reactions involve MeSiHCl₂ and Me₂SiHCl as intermediates. Consequently Me₂SiHCl with or without Me₂SiCl₂ and Alcl₃ deposited on carbon black as catalyst can undergo disproportionation to give Me₃SiCl.