biostudies-literatureUnknown25(65)Olaru MDeutsche ForschungsgemeinschaftFluoride abstraction from bis-m-terphenylelement fluorides (2,6-Mes<sub>2</sub> C<sub>6</sub> H<sub>3</sub> )<sub>2</sub> EF (E=P, As) generated the highly reactive phosphenium ion [(2,6-Mes<sub>2</sub> C<sub>6</sub> H<sub>3</sub> )<sub>2</sub> P]<sup>+</sup> and the arsenium ion [(2,6-Mes<sub>2</sub> C<sub>6</sub> H<sub>3</sub> )<sub>2</sub> As]<sup>+</sup> , 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<sub>2</sub> C<sub>6</sub> H<sub>3</sub> )<sub>2</sub> E]<sup>+</sup> (E=P, As) is in sharp contrast to the related stibenium ion [(2,6-Mes<sub>2</sub> C<sub>6</sub> H<sub>3</sub> )<sub>2</sub> Sb]<sup>+</sup> and bismuthenium ion [(2,6-Mes<sub>2</sub> C<sub>6</sub> H<sub>3</sub> )<sub>2</sub> Bi]<sup>+</sup> , 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.Chemistry (Weinheim an der Bergstrasse, Germany)14758-14761https://www.ebi.ac.uk/biostudies/studies/S-EPMC6900177biostudies-literatureTransient Phosphenium and Arsenium Ions versus Stable Stibenium and Bismuthenium Ions.PMC6900177Olaru MLork EBeckmann JDuvinage DMebs SfalseTransient Phosphenium and Arsenium Ions versus Stable Stibenium and Bismuthenium Ions.Fluoride abstraction from bis-m-terphenylelement fluorides (2,6-Mes<sub>2</sub> C<sub>6</sub> H<sub>3</sub> )<sub>2</sub> EF (E=P, As) generated the highly reactive phosphenium ion [(2,6-Mes<sub>2</sub> C<sub>6</sub> H<sub>3</sub> )<sub>2</sub> P]<sup>+</sup> and the arsenium ion [(2,6-Mes<sub>2</sub> C<sub>6</sub> H<sub>3</sub> )<sub>2</sub> As]<sup>+</sup> , 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<sub>2</sub> C<sub>6</sub> H<sub>3</sub> )<sub>2</sub> E]<sup>+</sup> (E=P, As) is in sharp contrast to the related stibenium ion [(2,6-Mes<sub>2</sub> C<sub>6</sub> H<sub>3</sub> )<sub>2</sub> Sb]<sup>+</sup> and bismuthenium ion [(2,6-Mes<sub>2</sub> C<sub>6</sub> H<sub>3</sub> )<sub>2</sub> Bi]<sup>+</sup> , 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.2019-01-01T00:00:00Z2019 Nov2021-02-20T18:16:08Z2020-05-21T23:33:19ZS-EPMC69001773140447210.1002/chem.201902520