瞬态膦离子和砷离子与稳定的锑离子和铋离子。
Transient Phosphenium and Arsenium Ions versus Stable Stibenium and Bismuthenium Ions.
机构信息
Institut für Anorganische Chemie und Kristallographie, Universität Bremen, Leobener Straße 7, 28359, Bremen, Germany.
Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany.
出版信息
Chemistry. 2019 Nov 22;25(65):14758-14761. doi: 10.1002/chem.201902520. Epub 2019 Oct 24.
Fluoride abstraction from bis-m-terphenylelement fluorides (2,6-Mes C H ) EF (E=P, As) generated the highly reactive phosphenium ion [(2,6-Mes C H ) P] and the arsenium ion [(2,6-Mes C H ) As] , which immediately underwent intramolecular electrophilic substitution and formation of an 1,2,4-trimethyl-6-mesityl-5-m-terphenyl-benzo[b]phospholium ion and an 1,2,4-trimethyl-6-mesityl-5-m-terphenyl-benzo[b]arsolium ion, respectively. The formation of the latter involved a methyl group migration from the ortho-position of a flanking mesityl group to the meta-position. This reactivity of [(2,6-Mes C H ) E] (E=P, As) is in sharp contrast to the related stibenium ion [(2,6-Mes C H ) Sb] and bismuthenium ion [(2,6-Mes C H ) Bi] , which have been recently isolated and fully characterized (Angew. Chem. Int. Ed. 2018, 57, 10080-10084). On the basis of DFT calculations, a mechanism for the rearrangement of the phosphenium and arsenium ions into the phospholium and arsolium ions is proposed, which is not feasible for the stibenium and bismuthenium ions.
双-间-三联苯氟化物（2,6-Mes C H ）EF（E=P、As）中的氟原子被夺走，生成了高活性的膦翁离子[(2,6-Mes C H ) P]和砷翁离子[(2,6-Mes C H ) As]，它们立即进行分子内亲电取代反应，分别形成 1,2,4-三甲基-6-均三甲苯基-5-间三联苯苯并[b]磷翁离子和 1,2,4-三甲基-6-均三甲苯基-5-间三联苯苯并[b]砷翁离子。后者的形成涉及到一个甲基从邻位均三甲苯基基团迁移到间位。[(2,6-Mes C H ) E]（E=P、As）的这种反应性与最近分离并充分表征的相关联苯翁离子[(2,6-Mes C H ) Sb]和铋翁离子[(2,6-Mes C H ) Bi]形成鲜明对比（Angew. Chem. Int. Ed. 2018, 57, 10080-10084）。基于 DFT 计算，提出了膦翁离子和砷翁离子重排为磷翁离子和砷翁离子的反应机理，该机理不适用于联苯翁离子和铋翁离子。
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