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Stable Mesoionic N‐Heterocyclic Olefins (mNHOs)
Author(s) -
Hansmann Max M.,
Antoni Patrick W.,
Pesch Henner
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201914571
Subject(s) - mesoionic , chemistry , deprotonation , reactivity (psychology) , boron , affinities , rhodium , proton , lewis acids and bases , computational chemistry , medicinal chemistry , stereochemistry , organic chemistry , catalysis , ion , medicine , physics , alternative medicine , pathology , quantum mechanics
We report a new class of stable mesoionic N‐heterocyclic olefins, featuring a highly polarized (strongly ylidic) double bond. The ground‐state structure cannot be described through an uncharged mesomeric Lewis‐structure, thereby structurally distinguishing them from traditional N‐heterocyclic olefins (NHOs). mNHOs can easily be obtained through deprotonation of the corresponding methylated N , N′ ‐diaryl‐1,2,3‐triazolium and N , N′ ‐diaryl‐imidazolium salts, respectively. In their reactivity, they represent strong σ‐donor ligands as shown by their coordination complexes of rhodium and boron. Their calculated proton affinities, their experimentally derived basicities (competition experiments), as well as donor abilities (Tolman electronic parameter; TEP) exceed the so far reported class of NHOs.