Stable Mesoionic N-Heterocyclic Olefins (mNHOs) |
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Authors: | Jun-Prof?Dr Max M Hansmann Patrick W Antoni Henner Pesch |
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Institution: | 1. Fakultät für Chemie und Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Str. 6, 44227 Dortmund, Germany;2. Georg-August Universität Göttingen, Institut für Organische und Biomolekulare Chemie, Tammannstr. 2, 37077 Göttingen, Germany |
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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 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. |
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Keywords: | Carben-Homologe Hauptgruppenchemie N-Heterozyklische Olefine Ylide |
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