Oxidative Addition of CH3I to Au‿/sup> in the Gas Phase

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• 作者：Satoru Muramatsu ; Kiichirou Koyasu ; Tatsuya Tsukuda
• 刊名：Journal of Physical Chemistry A
• 出版年：2016
• 出版时间：February 25, 2016
• 年：2016
• 卷：120
• 期：7
• 页码：957-963
• 全文大小：383K
• ISSN：1520-5215

文摘

Reaction of the atomic gold anion (Au^–) with CH₃I under high-pressure helium gas affords the adduct AuCH₃I^–. Photoelectron spectroscopy and density functional theory calculations reveal that in the AuCH₃I^– structure the I and CH₃ fragments of CH₃I are bonded to Au in a linear configuration, which can be viewed as an oxidative addition product. Theoretical studies indicate that oxidative addition proceeds in two steps: nucleophilic attack of Au^– on CH₃I, followed by migration of the leaving I^– to Au. This mechanism is supported by the formation of an ion-neutral complex, [Au^–···t-C₄H₉I], in the reaction of Au^– with t-C₄H₉I because of the activation barrier along the S_N2 pathway resulting from steric effects. Theoretical studies are conducted for the formation mechanism of AuI₂^–, which is observed as a major product. From the thermodynamic and kinetic viewpoints, we propose that AuI₂^– is formed via sequential oxidative addition of two CH₃I molecules to Au^–, followed by reductive elimination of C₂H₆. The results suggest that Au^– acts as a nucleophile to activate C(sp³)–I bond of CH₃I and induces the C–C coupling reaction of CH₃I.