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Stable Mesoionic N-Heterocyclic Olefins (mNHOs).

ABSTRACT: 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 ?-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.

SUBMITTER: Hansmann MM

PROVIDER: S-EPMC7154647 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature

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Stable Mesoionic N-Heterocyclic Olefins (mNHOs).

Hansmann Max M MM Antoni Patrick W PW Pesch Henner H

Angewandte Chemie (International ed. in English) 20200127 14

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 rep ...[more]

PMID: 31863704

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