ESR‐Vis/NIR Spectroelectrochemical Study of C70(CF3)2−. and C70(C2F5)2−. Radical Anions |
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| Authors: | Alexey A Popov Dr Natalia B Shustova Olga V Boltalina Dr Steven H Strauss Prof Lothar Dunsch Prof Dr |
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| Institution: | 1. Chemistry Department, Moscow State University, Leninskye Gory, 1, 119992 Moscow, Russia, Fax: (+7)?495‐932‐8846;2. Group of Electrochemistry and Conducting Polymers, Leibniz Institute for Solid State and Materials Research, P.O. Box 270116, 01171 Dresden, Germany, Fax: (+49)?351‐465‐9811;3. Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA, Fax: (+1)?970‐491‐1801 |
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| Abstract: | A spectroelectrochemical study of the two isostructural asymmetric perfluoroalkyl derivatives C1‐7,24‐C70(CF3)2 and C1‐7,24‐C70(C2F5)2 is presented. Reversible formation of their stable monoanion radicals is monitored by cyclic voltammetry and by in situ ESR‐Vis‐NIR spectroelectrochemistry. The ESR spectrum of the C70(CF3)2?. radical is a 1:3:3:1 quartet with a 19F hyperfine coupling constant (a(F)) of 0.323(4) G, demonstrating that the unpaired spin is coupled to only one of the two CF3 groups. The 13C satellites are assigned to specific carbon atoms. The ESR spectrum of the C70(C2F5)2?. radical is an apparent octet with an apparent a(F) value of 0.83(2) G. DFT calculations suggest that this pattern is due to the superposition of spectra for four nearly isoenergetic C70(C2F5)2?. conformers. Time‐dependent DFT calculations suggest that the NIR band at 1090 nm exhibited by both C70(Rf)2?. radical anions is assigned to the SOMO→LUMO+3 transition. The analogous NIR band exhibited by the closed‐shell C70(CF3)22? dianion was blue‐shifted to 1000 nm. |
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| Keywords: | density functional calculations ESR spectroscopy fullerenes spectroelectrochemistry Vis/NIR spectroscopy |
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