Crystalline Radicals Derived from Classical N‐Heterocyclic Carbenes |
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| Authors: | Dennis Rottschäfer Beate Neumann Dr. Hans‐Georg Stammler Dr. Maurice van Gastel Dr. Diego M. Andrada Priv.‐Doz. Dr. Rajendra S. Ghadwal |
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| Affiliation: | 1. hhtp://www.ghadwalgroup.de 0000-0002-4810-9203 Anorganische Molekülchemie und Katalyse, Lehrstuhl für Anorganische Chemie und Strukturchemie, Centrum für Molekulare Materialien, Fakult?t für Chemie, Universit?t Bielefeld, Bielefeld, Germany;2. Anorganische Molekülchemie und Katalyse, Lehrstuhl für Anorganische Chemie und Strukturchemie, Centrum für Molekulare Materialien, Fakult?t für Chemie, Universit?t Bielefeld, Bielefeld, Germany;3. Max-Planck-Institut für Kohlenforschung, Mülheim an der Ruhr, Germany;4. Allgemeine und Anorganische Chemie, Universit?t des Saarlandes, Campus C4.1, Saarbrücken, Germany |
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| Abstract: | One‐electron reduction of C2‐arylated 1,3‐imidazoli(ni)um salts (IPrAr)Br (Ar=Ph, 3 a ; 4‐DMP, 3 b ; 4‐DMP=4‐Me2NC6H4) and (SIPrAr)I (Ar=Ph, 4 a ; 4‐Tol, 4 b ) derived from classical NHCs (IPr=:C{N(2,6‐iPr2C6H3)}2CHCH, 1 ; SIPr=:C{N(2,6‐iPr2C6H3)}2CH2CH2, 2 ) gave radicals [(IPrAr)]. (Ar=Ph, 5 a ; 4‐DMP, 5 b ) and [(SIPrAr)]. (Ar=Ph, 6 a ; 4‐Tol, 6 b ). Each of 5 a , b and 6 a , b exhibited a doublet EPR signal, a characteristic of monoradical species. The first solid‐state characterization of NHC‐derived carbon‐centered radicals 6 a , b by single‐crystal X‐ray diffraction is reported. DFT calculations indicate that the unpaired electron is mainly located at the original carbene carbon atom and stabilized by partial delocalization over the adjacent aryl group. |
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| Keywords: | density functional calculations EPR spectroscopy N-heterocyclic carbenes radicals X-ray diffraction |
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