FT-IR Study of the Gas-Phase Autoxidation of Trimethylgermane
摘要:
The kinetics and mechanism of the autoxidation of trimethylgermane in the gas phase has been investigated in the temperature range 493-533 K using Fourier transform infrared spectroscopy. Over a wide molar ratio of reactants (Me3GeH:O2 ratio in the range (1:1)-(1:31)) the loss of Me3GeH follows second-order kinetics but is independent of oxygen abundance. The products of the reaction are heyamethyldigermoxane, Me3GeOGeMe3, and water. No other products are apparent. For a 1:10 Me3GeH:02 molar ratio, second-order rate constants vary from 2.46 mol-1 de s-1 at 493 K to 64.1 mol-1 dm3 s-1 at 533 K. The activation energy for the process -is determined to be 190 +/- 19 kJ mol-1. The proposed mechanism involves an initial abstraction of the hydridic hydrogen atom from germanium followed by the reaction of the trimethylgermyl radical thus formed with oxygen, giving the (trimethylgermyl)peroxyl radical. This radical is converted into trimethylgermyl hydroperoxide, Me3GeOOH, by further H-abstraction from Me3GeH and undergoes O-O bond fission to form (trimethylgermyl)oxyl and hydroxyl radicals. The radicals thus produced propagate the reaction by H-abstraction from Me3GeH, forming the intermediate Me3GeOH and water. Hexamethyldigermoxane is subsequently formed by self-condensation of two Me3GeOH molecules.
Metal-Mediated Production of Isocyanates, R<sub>3</sub>ENCO from Dinitrogen, Carbon Dioxide, and R<sub>3</sub>ECl
作者:Andrew J. Keane、Wesley S. Farrell、Brendan L. Yonke、Peter Y. Zavalij、Lawrence R. Sita
DOI:10.1002/anie.201502293
日期:2015.8.24
A highly efficient and versatile chemical cycle has been developed for the production of isocyanates through the molecular fixation of N2, CO2 and R3ECl (E=C, Si, and Ge). Key steps include a ‘one‐pot’ photolytic NN bond cleavage of a Group 6 dinuclear dinitrogen complex with in situ trapping by R3ECl to provide a metal terminal imido complex that can engage in simultaneous nitrene‐group transfer
Characterisation of bis-methylgermanium and bis-methylsilicon carbodi-imides and their reactivity with protic reagents
作者:John E. Drake、Raymond T. Hemmings、Ernest Henderson
DOI:10.1039/dt9760000366
日期:——
bismethylsilicon carbodi-imides have been prepared in high yield by halide metathesis reactions with lead(II), silver(I), or silicon(IV) species. The new derivatives in the series of general formula (MenH3 –nMN:)2C (MSi or Ge; n= 1, 2 or 3) have been characterised by 1H n.m.r., i.r., and Raman spectroscopy as well as mass spectrometry and cleavage reactions. The utility of the germanium carbodi-imides as synthetic
通过与铅(II),银(I)或硅(IV)物种进行卤化物易位反应,可以高收率制备双甲基锗和双甲基硅碳二亚胺。通式(Me n H 3 – n MN :)2 C(M Si或Ge;n = 1、2或3)系列中的新导数的特征是1H nmr,ir和Raman光谱以及质谱和裂解反应。第六种锗原子容易裂解Ge-N键,导致硫属锗烷及其相关衍生物的形成(Me n H 3 – n葛)2 E(E = O,S,Se或Te)和Me ñ ħ 3 - ñ GESR(R = Me中,卜吨,pH值,的MeC(O),或-CH 2 CH 2 - )。比较研究表明,在碳碳化二亚胺硅中,Si-N键不易受较重的硫属元素醇分解的影响。
Photochemical reactions of 2-(pentamethyldisilanyl)furan and 2-(pentamethyldigermanyl)furan. Formation of a radical pair
Photochemicalreactions of 2-(pentamethyldisilanyl)furan and 2-(pentamethyldigermanyl)furan have been investigated by chemical trapping experiments and laser flash-photolysis. On irradiation, the furylated catenates of Group 14 elements undergo silicon-silicon σ bond and germanium-germanium σ bond homolysis to give a pair of silyl radicals and germyl radicals, respectively. In CCl4, these radicals