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Author Eaton, S. S. ♦ Kee, A. ♦ Konda, R. ♦ Eaton, G. R. ♦ Trulove, P. C. ♦ Carlin, R. T.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword MATERIALS SCIENCE ♦ CHEMISTRY ♦ PHYSICS ♦ FULLERENES ♦ NMR SPECTRA ♦ ELECTRON SPIN RESONANCE ♦ SPIN ♦ RELAXATION ♦ SOLUTIONS ♦ TOLUENE ♦ ACETONITRILE ♦ DMSO ♦ ANIONS ♦ VOLTAMETRY ♦ JAHN-TELLER EFFECT ♦ TEMPERATURE DEPENDENCE
Abstract To assess the effect of solvent on the properties of C{sub 60} anions, solutions of C{sub 60}{sup -} and C{sub 60}{sup 3-} were generated electrochemically in 4:1 toluene:acetonitrile or DMSO containing 0.1 M tetrabutylammonium hexafluoro-phosphate. The anions were characterized by NIR spectroscopy and square-wave voltammetry. In both solvents continuous wave (CW) electron paramagnetic resonance (EPR) spectra at 8 K are axial for C{sub 60}{sup -} and rhombic for C{sub 60}{sup 3-}, consistent with increasing distortion of the anion with increasing addition of electrons to the LUMO of C{sub 60}. The line shapes in the wings of the spectra, decreasing anisotropy of the spectra with increasing temperature, faster phase memory relaxation rates in the wings of the spectra, and distribution of values of the spin-lattice relaxation rate (1/T{sub 1}) provide evidence for a distribution of Jahn-Teller distorted forms and increasing rates of interconversion between these forms with increasing temperature. These properties are similar in the two solvents, despite substantial differences in solvent polarity. Extrapolation of the temperature dependence of 1/T{sub 1} measured below 30 K suggests that the line widths above 70 K are relaxation determined. Above about 70 K the line widths of the CW spectra broaden as increasing mobility of the solute/solvent increases the rate of spin-lattice relaxation. 52 refs., 9 figs.
ISSN 00223654
Educational Use Research
Learning Resource Type Article
Publisher Date 1996-04-25
Publisher Place United States
Journal Journal of Physical Chemistry
Volume Number 100
Issue Number 17


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