Factors Influencing the Outcomes of Intermolecular C鈥揌 Activations of Hydrocarbons Initiated by CpW(NO)(CH2CMe3)(畏3-allyl) Complexes (Cp = 畏5-C5M

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• 作者：Rhett A. Baillie ; Tommy Tran ; Kathryn M. Lalonde ; Jenkins Y. K. Tsang ; Michelle E. Thibault ; Brian O. Patrick ; Peter Legzdins
• 刊名：Organometallics
• 出版年：2012
• 出版时间：February 13, 2012
• 年：2012
• 卷：31
• 期：3
• 页码：1055-1067
• 全文大小：636K
• 年卷期：v.31,no.3(February 13, 2012)
• ISSN：1520-6041

文摘

Gentle thermolyses of CpW(NO)(CH₂CMe₃)(畏³-allyl) complexes (Cp = 畏⁵-C₅Me₅ (Cp*), 畏⁵-C₅Me₄H (Cp鈥?) in neat hydrocarbon solutions result in the loss of neopentane from the metal鈥檚 coordination spheres and the transient formation of the 16-electron (16e) intermediate species CpW(NO)(畏²-allene) and/or CpW(NO)(畏²-diene). These transient intermediates can react with hydrocarbon substrates, RH (R = alkyl, aryl), to form three different types of organometallic products. The first products are the desired CpW(NO)(畏³-allyl)(畏¹-R) complexes that result from the selective single activation of a C鈥揌 bond of RH. The second class of products involves CpW(NO)(H)[畏³-(R)-allyl] complexes that are isomers of the CpW(NO)(畏³-allyl)(畏¹-R) compounds resulting from an intramolecular R/allyl H exchange. Finally, the third type of products contains CpW(NO)(H)[畏³-hydrocarbyl] species that result from three successive C鈥揌 activations of hydrocarbon substrates such as R鈥睠H₂CH₂CH₃ and loss of the original allyl ligand. Just which organometallic products ultimately result from the reactions of the CpW(NO)(CH₂CMe₃)(畏³-allyl) complexes with hydrocarbons depends on several factors, including the natures of the cyclopentadienyl and allyl ligands, the hydrocarbon substrates themselves, the electron density at the metal centers, and the experimental conditions employed. This article documents these dependences and identifies the optimum CpW(NO)(CH₂CMe₃)(畏³-allyl) compounds and experimental conditions for effecting the selective single C鈥揌 bond activations of hydrocarbon substrates such as benzene as a representative arene and methylcyclohexane as a representative alkane. During the course of these investigations all new organometallic complexes have been characterized by conventional spectroscopic methods, and the solid-state molecular structures of several of them have been established by single-crystal X-ray crystallographic analyses.