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Long-Lived Circularly Polarized Phosphorescence in Helicene-NHC Rhenium(I) Complexes: The Influence of Helicene,Halogen, and Stereochemistry on Emission Properties |
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| Authors: | Etienne S Gauthier Dr Laura Abella Dr Nora Hellou Dr Benoît Darquié Dr Elsa Caytan Dr Thierry Roisnel Dr Nicolas Vanthuyne Dr Ludovic Favereau Dr Monika Srebro-Hooper Prof J A Gareth Williams Prof Jochen Autschbach Dr Jeanne Crassous |
| Institution: | 1. Univ Rennes, CNRS, ISCR—UMR 6226 ScanMat – UMS 2001, 35000 Rennes, France;2. Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY, 14260 USA;3. Laboratoire de Physique des Lasers, Université Paris 13, CNRS, Villetaneuse, France;4. Aix Marseille University, CNRS Centrale Marseille, iSm2, 13284 Marseille, France;5. Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland;6. Department of Chemistry, Durham University, Durham, DH1 3LE UK |
| Abstract: | The first enantiopure chiral-at-rhenium complexes of the form fac-ReX(CO)3(:C^N) have been prepared, where :C^N is a helicene-N-heterocyclic carbene (NHC) ligand and X=Cl or I. These have complexes show strong changes in the emission characteristics, notably strongly enhanced phosphorescence lifetimes (reaching 0.7 ms) and increased circularly polarized emission (CPL) activity, as compared to their parent chiral models lacking the helicene unit. The halogen along with its position within the dissymmetric stereochemical environment strongly affect the photophysics of the complexes, particularly the phosphorescence quantum yield and lifetime. These results give fresh insight into fine tuning of photophysical and chiroptical properties of Re-NHC systems. |
| Keywords: | circularly polarized emission helicenes N-heterocyclic carbenes phosphorescence rhenium(I) |