Proton-Coupled Electron Transfer in the Reduction of Arenes by SmI2鈥揥ater Complexes

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• 作者：Tesia V. Chciuk ; Robert A. Flowers ; II
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：September 9, 2015
• 年：2015
• 卷：137
• 期：35
• 页码：11526-11531
• 全文大小：382K
• ISSN：1520-5126

文摘

The presence of water has a significant impact on the reduction of substrates by SmI₂. The reactivity of the Sm(II)-water reducing system and the relationship between sequential or concerted electron-transfer, proton-transfer is not well understood. In this work, we demonstrate that the reduction of an arene by SmI₂-water proceeds through an initial proton-coupled electron transfer. The use of thermochemical data available in the literature shows that upon coordination of water to Sm(II) in THF, significant weakening of the O鈥揌 bond occurs. The derived value of nearly 73 kcal/mol for the decrease in the bond dissociation energy of the O鈥揌 bond in the Sm(II)鈥搘ater complex is the largest reported to date for low-valent reductants containing bound water.