Consequences of the one-electron reduction and photoexcitation of unsymmetric bis-imidazolium salts: dedicated to Professor Gottfried Huttner
Coupling of uronium salts with in situ generated N-heterocyclic carbenes provides straightforward access to symmetrical [4]2+ and unsymmetrical bis-imidazolium salts [6]2+ and [9]2+. As indicated by cyclic and square-wave voltammetry, [6]2+ and [9]2+ can be (irreversibly) reduced by one electron. Th...
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| Main Authors: | , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
12 July 2012
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| In: |
Chemistry - a European journal
Year: 2012, Volume: 18, Issue: 34, Pages: 10677-10688 |
| ISSN: | 1521-3765 |
| DOI: | 10.1002/chem.201200323 |
| Online Access: | Verlag, Volltext: http://dx.doi.org/10.1002/chem.201200323 Verlag, Volltext: https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.201200323 
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| Author Notes: | Verena Gierz, Jascha Melomedov, Christoph Förster, Christine Deißler, Frank Rominger, Doris Kunz, and Katja Heinze |
| Summary: | Coupling of uronium salts with in situ generated N-heterocyclic carbenes provides straightforward access to symmetrical [4]2+ and unsymmetrical bis-imidazolium salts [6]2+ and [9]2+. As indicated by cyclic and square-wave voltammetry, [6]2+ and [9]2+ can be (irreversibly) reduced by one electron. The initially formed radicals [6].+ and [9].+ undergo further reactions, which were probed by EPR spectroscopy and density functional calculations. The final products of the two-electron reduction are the two carbenes. Upon irradiation with UV light both [6]2+ and [9]2+ emit at room temperature in solution but with dramatically different characteristics. The different fluorescence behavior is analyzed by emission spectroscopy and interpreted by using time-dependent density functional calculations as largely due to different excited-state dynamics of [6]2+ and [9]2+. The geometries of both radicals [6].+ and [9].+ and excited states [6]2+* and [9]2+* are substantially different from those of the parent ground-state molecules. |
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| Item Description: | Gesehen am 13.06.2018 |
| Physical Description: | Online Resource |
| ISSN: | 1521-3765 |
| DOI: | 10.1002/chem.201200323 |