C<sub>(sp3)</sub>–H Oxidative Addition at Tantalocene Hydrides
作者:Steven M. Rehbein、Matthew J. Kania、Sharon R. Neufeldt
DOI:10.1021/acs.organomet.2c00672
日期:——
well-known to activate alkane C–H bondsthrough oxidative addition, this mechanistic step is atypical for early transition metals. Instead, prior examples of intermolecular C(sp3)–H activation at early transition metals tend to proceed through σ-bond metathesis or 1,2-addition mechanisms. Recent theoretical work suggested that tantalocenes may be capable of activating aliphatic C–H bonds by oxidative addition
虽然后过渡金属通过氧化加成激活烷烃 C-H 键是众所周知的,但这种机制步骤对于早期过渡金属来说是不典型的。相反,早期过渡金属的分子间 C (sp3) –H 活化的先前示例倾向于通过 σ 键复分解或 1,2-加成机制进行。最近的理论工作表明,茂钽可能能够通过氧化加成激活脂肪族 C-H 键。在此,我们证明单烷基取代的茂钽R Cp 2 TaH 3在 C 6 D 6存在下在烷基取代基“R”上进行 H/D 交换,表明分子内 C (sp3)-H 激活发生。此外,发现 Cp 2 TaH 3催化 H 2与辛烷-d 18和甲基环己烷 - d 14之间的 H/D 交换,表明分子间 C (sp3) -H 活化步骤的参与。密度泛函理论计算支持瞬态 Ta(III) 处的 C (sp3) –H 氧化加成,这是一个以前从未见过的用于烷烃分子间活化的机理步骤。
Photochemical generation of 16-electron [Rh(η<sup>5</sup>)-C<sub>5</sub>H<sub>5</sub>)-(PMe<sub>3</sub>)] and [Ir(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)(PMe<sub>3</sub>)] in low-temperature matrices: evidence for methane activation
作者:Martin G. Partridge、Andrew McCamley、Robin N. Perutz
DOI:10.1039/dt9940003519
日期:——
The photochemical reactions of [Rh(eta(5)-C5H5)(PMe(3))(H)(2)] and [Ir(eta(5)-C5H5)(PMe(3))(H)(2)] have been studied in Ar, CH4, N-2 and CO-doped argon matrices by IR and UV/VIS spectroscopy. The UV photolysis in argon matrices results in the formation of the 16-electron complexes [M(eta(5)-C5H5)(PMe(3))] with characteristic visible absorption maxima (M = Rh, lambda(max) 399 and 488 nm; M = Ir, lambda(max) 436 and 526 nm). The reaction is partially reversed by long-wavelength photolysis. The conversion of [Rh(eta(5)-C5H5)(PMe(3))(H)(2)] to [Rh(eta(5)-C5H5)(PMe(3))(Me)H] on photolysis in methane matrices is confirmed by extensive isotopic labelling studies and by the use of alternative precursors for the methyl hydride, viz. [Rh(eta(5)-C5H5)(PMe(3))(eta(2)-C6F6)] and [Rh(eta(5)-C5H5)(PMe(3))(C2H4)]. Evidence has also been obtained to show that irradiation of [Ir(eta(5)-C5H5)(PMe(3))(H)(2)] in methane yields [Ir(eta(5)-C5H5)(PMe(3))(Me)H]. Photolysis of [M(eta(5)-C5H)(PMe(3))(H)2] in N-2 and CO-doped Ar matrices generates [M(eta(5)-C5H5)(PMe(3))L] (M = Rh or Ir, L = N-2 or CO).
Periana, Roy A.; Bergman, Robert G., Organometallics, 1984, vol. 3, # 3, p. 508 - 510
作者:Periana, Roy A.、Bergman, Robert G.
DOI:——
日期:——
The oxidation of alkanes with dimethyldioxirane; a new mechanistic insight
Primary kinetic isotope effects were measured for the oxidation of cyclohexane and methylcyclohexane with DMDO in solution and in the gas phase. These experiments suggest an electrophilic oxygen insertion mechanism for the oxidation of alkanes by DMDO. (C) 1997 Published by Elsevier Science Ltd.
Arylruthenium(III) Porphyrin-Catalyzed C–H Oxidation and Epoxidation at Room Temperature and [Ru<sup>V</sup>(Por)(O)(Ph)] Intermediate by Spectroscopic Analysis and Density Functional Theory Calculations
作者:Ka-Pan Shing、Bei Cao、Yungen Liu、Hung Kay Lee、Ming-De Li、David Lee Phillips、Xiao-Yong Chang、Chi-Ming Che
DOI:10.1021/jacs.8b04470
日期:2018.6.6
metal catalysts for efficient oxidation of hydrocarbons and identification of the reactive intermediates in the oxidation catalysis are long-standing challenges. In the rapid hydrocarbon oxidation catalyzed by ruthenium(IV) and -(III) porphyrins, the putative Ru(V)-oxo intermediates remain elusive. Herein we report that arylruthenium(III) porphyrins are highly active catalysts for hydrocarbon oxidation