Infrared and Raman spectra, conformations and ab initio calculations of ethyl bromosilane and ethyl dibromosilane
摘要:
Ethyl bromosilane (CH(3)CH(2)SiH(2)Br) and ethyl dibromosilane (CH(3)CH(2)SiHBr(2)) were synthesized and their infrared and Raman spectra determined in vapour (LR), liquid (Raman), amorphous solid, and crystalline states. Additional infrared spectra of the compounds isolated in argon and nitrogen matrices at 5 K were recorded before and after annealing to temperatures in the range of 15-35 K. Raman spectra of the liquid were recorded at various temperatures between 295 and 153 K. Both the spectra showed the existence of two conformers - anti and gauche - present in the fluid and amorphous phases. The crystals contained the gauche conformer for bromide and anti conformer for the dibromide in accordance with the results for the chloro and iodo homologues. The enthalpy differences in the liquids measured in Raman gave: Delta H (anti-gauche) = 1.8 +/- 0.3 and Delta H (gauche anti) = 2.1 +/- 0.3 kJ mol(-1), respectively.Ab initio calculations were performed using the Gaussian 94 program with the HF/6-311G* basis set and gave optimized geometries, infrared and Raman intensities and scaled vibrational frequencies for the anti and gauche conformers. The conformational energies were calculated to be 0.02 kJ mol(-1) for ethyl bromosilane and 0.3 kJ mol(-1) for ethyl dibromosilane with the anti and gauche conformers having the lower energy, respectively. (C) 1999 Elsevier Science B.V. All rights reserved.
Lewis Base Catalyzed Selective Chlorination of Monosilanes
作者:Alexander G. Sturm、Julia I. Schweizer、Lioba Meyer、Tobias Santowski、Norbert Auner、Max C. Holthausen
DOI:10.1002/chem.201803921
日期:2018.12.3
A preparatively facile, highly selective synthesis of bifunctional monosilanes R2SiHCl, RSiHCl2 and RSiH2Cl is reported. By chlorination of R2SiH2 and RSiH3 with concentrated HCl/ether solutions, the stepwise introduction of Si−Cl bonds is readily controlled by temperature and reaction time for a broad range of substrates. In a combined experimental and computational study, we establish a new mode
Iminophosphorane-based [P2N2] rhodium complexes: synthesis, reactivity, and application in catalysed transfer hydrogenation of polar bonds
作者:Antoine Buchard、Elina Payet、Audrey Auffrant、Xavier Le Goff、Pascal Le Floch
DOI:10.1039/c0nj00299b
日期:——
[Rh(P2N2)X] complexes (2-X, X = Cl, BF4) featuring a tetradentate iminophosphorane phosphine ligand were synthesised and characterised. X-Ray analysis provides evidence for a square planar geometry without coordination of the chloride anion. These complexes proved to be air-sensitive, and their oxidation to Rh(III) complexes 3-X was observed in air. The controlled reaction of 2-BF4 with one equivalent
[Rh(P 2 N 2)X]络合物(2-X,X =氯,BF 4)具有四齿亚氨基膦膦合成并表征了配体。X射线分析为正方形平面几何结构提供了证据,而无需协调氯化物负离子。这些配合物被证明对空气敏感,并且它们被氧化为铑(III)在空气中观察到配合物3-X。2-BF 4与一当量的受控反应六氯乙烷得到[Rh(P 2 N 2)Cl 2(BF 4)](3-BF 4)。3-Cl的直接合成也可以通过[P 2 N 2 ]配体与[氯化铑(THT)3](THT = 四氢噻吩)。的反应性铑(I)进一步研究了配合物2,尽管在长时间加热下在1 atm H 2下观察到分解,但未观察到与硅烷,芳基卤化物或频哪醇硼烷的反应。有趣的是,在用硅烷或硅烷处理后,通过NMR观察到了络合物3-Cl的还原。异丙醇钠。因此,络合物3-Cl被用于极性键的催化转移氢化。芳香族和脂肪族酮的还原可以使用1%的催化剂和10%的催化剂进行异丙醇钠,而在这些条件下亚胺会部分还原。
Towards Naked Zinc(II) in the Condensed Phase: A Highly Lewis Acidic Zn
<sup>II</sup>
Dication Stabilized by Weakly Coordinating Carborate Anions
作者:Nicolas Adet、David Specklin、Christophe Gourlaouen、Thibault Damiens、Béatrice Jacques、Rudolf J. Wehmschulte、Samuel Dagorne
DOI:10.1002/anie.202012287
日期:2021.1.25
The employment of the hexyl‐substituted anion [HexCB11Cl11]− allowed the synthesis of a ZnII species, Zn[HexCB11Cl11]2, 3, in which the Zn2+ cation is only weakly coordinated to two carborate counterions and that is soluble in low polarity organic solvents such as bromobenzene. DOSY NMR studies show the facile displacement of at least one of the counterions, and this near nakedness of the cation results
Hydrosilylation of Olefins with Monosilane in the Presence of Lithium Aluminum Hydride
作者:Mineo Kobayashi、Masayoshi Itoh
DOI:10.1246/cl.1996.1013
日期:1996.12
produced from 1-hexene and SiH4. Ethylsilane was produced from ethylene and SiH4. The reaction mechanism involving SiH4 and the alkyl anion, which is formed by the interaction between LiAlH4 and the olefin, has been proposed.
Catalytic Disproportionation of Alkylsilanes over Sulfated ZrO<sub>2</sub>
作者:Hideo Fujisawa、Tsutomu Yamaguchi
DOI:10.1246/cl.1993.593
日期:1993.4
Gas phase heterogeneous catalytic conversions of diethylsilane(E2), triethylsilane(E3) and diethyldimethylsilane(E2M2) were examined at 373–573 K in a closed recirculation reactor by using a sulfated ZrCO2(SO3/ZrO2) catalyst. The catalyst exhibited high disproportionation activity even at 373 K.
使用硫酸化 ZrCO2(SO3/ZrO2)催化剂,在密闭循环反应器中于 373-573 K 温度下考察了二乙基硅烷(E2)、三乙基硅烷(E3)和二乙基二甲基硅烷(E2M2)的气相异相催化转化。即使在 373 K 下,该催化剂也表现出很高的歧化活性。