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Transient Phosphenium and Arsenium Ions versus Stable Stibenium and Bismuthenium Ions
Author(s) -
Olaru Marian,
Duvinage Daniel,
Lork Enno,
Mebs Stefan,
Beckmann Jens
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201902520
Subject(s) - chemistry , ion , reactivity (psychology) , medicinal chemistry , electrophile , intramolecular force , fluoride , stereochemistry , catalysis , inorganic chemistry , organic chemistry , medicine , alternative medicine , pathology
Abstract Fluoride abstraction from bis‐ m ‐terphenylelement fluorides (2,6‐Mes 2 C 6 H 3 ) 2 EF (E=P, As) generated the highly reactive phosphenium ion [(2,6‐Mes 2 C 6 H 3 ) 2 P] + and the arsenium ion [(2,6‐Mes 2 C 6 H 3 ) 2 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 2 C 6 H 3 ) 2 E] + (E=P, As) is in sharp contrast to the related stibenium ion [(2,6‐Mes 2 C 6 H 3 ) 2 Sb] + and bismuthenium ion [(2,6‐Mes 2 C 6 H 3 ) 2 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.