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Anion radicals of mono‐ and bisfunctionalized [60]fullerene derivatives. Evidence for 13 C satellites in their EPR spectra
Author(s) -
Brezová V.,
Staško A.,
Rapta P.,
Guldi D. M.,
Asmus K.D.,
Dinse K.P.
Publication year - 1997
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/(sici)1097-458x(199711)35:11<795::aid-omr180>3.0.co;2-0
Subject(s) - chemistry , electron paramagnetic resonance , spectral line , adduct , radical , ion , methylene , fullerene , line width , carbon fibers , electrochemistry , nmr spectra database , crystallography , medicinal chemistry , nuclear magnetic resonance , organic chemistry , physics , materials science , electrode , astronomy , composite number , optics , composite material
Upon photo‐ and electrochemical in situ reduction of [60]fullerene derivatives, C 60 [C(COOEt) 2 ] n ( n =1, 2), characteristic single‐line EPR spectra are observed which are attributable to the corresponding radical anions. Monofunctionalized C 60 [C(COOEt) 2 ] shows a reduction behavior similar to pristine C 60 , i.e. formation of a primary radical A which converts with time into B with a peak‐to‐peak width of pp A ≈0.1 mT and g A =2.0000, pp B ≈0.05 mT and g B =2.0006. In contrast, the EPR spectra of the four bis‐adducts‐{equatorial, trans ‐1, trans ‐2 and trans ‐3 C 60 [C(COOEt) 2 ] 2 } are dominated by only one narrow line with pp ranging from 0.007 to 0.03 mT and g values between 2.0002 and 2.0004. Their relative width changes with the regiosteric positioning of the functionalizing addends. Well resolved spectra reveal 13 C satellites, originating from 12–20 carbon nuclei. Slightly higher splittings ( a 13C ≈0.2 mT) for four carbon nuclei suggest higher spin density at the keto group carbons of the bis(ethoxycarbonyl)methylene substituents. © 1997 John Wiley & Sons, Ltd.