Proton, muon and ¹³C hyperfine coupling constants of C₆₀X and C₇₀X (X = H, Mu)
Jean-Claude Brodovitch1, Brenda Addison-Jones, Khashayar Ghandi
1Department of Chemistry, Simon Fraser University, Burnaby BC V5A 1S6, Canada. percival@sfu.ca.
Abstract:
The reaction of H atoms with fullerene C70 has been investigated by identifying the radical products formed by addition of the atom muonium (Mu) to the fullerene in solution. Four of the five possible radical isomers of C70Mu were detected by avoided level-crossing resonance (μLCR) spectroscopy, using a dilute solution of enriched (13)C70 in decalin. DFT calculations were used to predict muon and (13)C isotropic hyperfine constants as an aid to assigning the observed μLCR signals. Computational methods were benchmarked against previously published experimental data for (13)C60Mu in solution. Analysis of the μLCR spectrum resulted in the first experimental determination of (13)C hyperfine constants in either C70Mu or C70H. The large number of values confirms predictions that the four radical isomers have extended distributions of unpaired electron spin.
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