Straightforward Access to Stable, 16-Valence-Electron Phosphine-Stabilized Fe0 Olefin Complexes and Their Reactivity

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• 作者：Benjamin Burcher ; Kevin J. Sanders ; Ladislav Benda ; Guido Pintacuda ; Erwann Jeanneau ; Andreas A. Danopoulos ; Pierre BraunsteinHélène Olivier-Bourbigou ; Pierre-Alain R. Breuil
• 刊名：Organometallics
• 出版年：2017
• 出版时间：February 13, 2017
• 年：2017
• 卷：36
• 期：3
• 页码：605-613
• 全文大小：527K
• ISSN：1520-6041

文摘

The use of the dialkene divinyltetramethyldisiloxane (dvtms) allows easy access to the reactive 16-valence-electron complexes [Fe⁰(L-L)(dvtms)] (L-L = dppe (1,2-bis(diphenylphosphino)ethane; 1), dppp (1,2-bis(diphenylphosphino)propane; 2), pyNMeP(ⁱPr)₂ (N-(diisopropylphosphino)-N-methylpyridin-2-amine; 4), dipe (1,2-bis(diisopropylphosphino)ethane; 5)) and [Fe⁰(L)₂(dvtms)] (L = PMe₃; 3) by a mild reductive route using AlEt₂(OEt) as reducing agent. In contrast, by the same methodology, the 18-valence-electron complexes [Fe⁰(L-L)₂(ethylene)] (L-L = dppm (1,2-bis(diphenylphosphino)methane; 6), dppa (1,2-bis(diphenylphosphino)amine; 7), dppe (8)) were obtained, which do not contain dvtms. In addition, a combined DFT and solid-state paramagnetic NMR methodology is introduced for the structure determination of 5. A comparative study of the reactivity of 1, 2, 4–6, and 8 with 3-hexyne highlights emerging mechanistic implications for C–C coupling reactions using these complexes as catalysts.