Leong Derek W, Gogoi Achyut R, Maity Tapas, Lee Chun-I, Bhuvanesh Nattamai, Gutierrez Osvaldo, Ozerov Oleg V
Department of Chemistry, Texas A&M University, TAMU - 3255, College Station, Texas, USA, 77842.
Angew Chem Int Ed Engl. 2025 Apr 7;64(15):e202422190. doi: 10.1002/anie.202422190. Epub 2025 Mar 2.
Lewis acids play a central role in a large variety of chemical transformations. The reactivity of the strongest Lewis acids is typically studied in the context of affinity towards hard bases, such as fluoride or oxygenous species. Carbocations can be viewed as soft Lewis acids, possessing significant affinity for softer bases, such as hydride. This work presents the ambient-temperature isolation of salts of the perfluorotrityl cation ((CF)C or FTr) in combination with halogenated carborane anions. The FTr cation exhibits remarkable hydride affinity, illustrated by the observation of hydride abstraction from dihydrogen, and of the rapid abstraction of hydride from -CH-groups in alkanes. Theoretical studies support the favorability of hydride abstraction from dihydrogen, and indicate that the hydride abstraction from alkanes proceeds via a concerted hydride transfer process that is sensitive to steric effects.
路易斯酸在各种各样的化学转化过程中起着核心作用。最强路易斯酸的反应活性通常是在其对硬碱（如氟化物或含氧化合物）的亲和力背景下进行研究的。碳正离子可被视为软路易斯酸，对较软的碱（如氢化物）具有显著的亲和力。这项工作展示了全氟三苯甲基阳离子（(CF)C或FTr）的盐与卤代碳硼烷阴离子在室温下的分离。FTr阳离子表现出显著的氢化物亲和力，这体现在观察到其从氢气中夺取氢化物，以及从烷烃中的 -CH- 基团快速夺取氢化物。理论研究支持了从氢气中夺取氢化物的有利性，并表明从烷烃中夺取氢化物是通过一个对空间效应敏感的协同氢化物转移过程进行的。
