Single-electron reduction of C₆₀ with a carbon radical: formation of the Crystal Violet cation–fulleride ion salt†

Abstract

Whereas many carbon radicals are known to add to C₆₀, the reaction of Crystal Violet radical 1^• with C₆₀ resulted in single-electron transfer, leading to a carbocation–carbanion salt 1⁺C₆₀^•–: the product was isolated as microcrystalline powder and was characterized by EPR, VIS-NIR and NMR spectroscopy.

References

1. For reviews, see J. R. Morton, F. Negri and K. F. Preston, Acc. Chem. Res., 1998, 31, 63; R. Taylor, in The Chemistry of Fullerenes, ed. R. Taylor, World Scientific, Singapore, 1995, ch. 13;; A. Hirsch, The Chemistry of the Fullerenes, Thieme, Stuttgart, 1994, ch. 6.
2. P. J. Krusic, E. Wasserman, P. N. Keizer, J. R. Morton and K. F. Preston, Science, 1991, 254, 1183.
3. P. J. Krusic, E. Wasserman, B. A. Perkinson, B. Malone, E. R. Holler, Jr., P. N. Keizer, J. R. Morton and K. F. Preston, J. Am. Chem. Soc., 1991, 113, 6724.
4. P. J. Fagan, P. J. Krusic, C. N. McEwen, J. Lazar, D. H. Parker, N. Herron and E. Wasserman, Science, 1993, 262, 404.
5. Half-wave potentials, measured in 1,2-dichlorobenzene: T. Kitagawa, T. Tanaka, Y. Takata, K. Takeuchi and K. Komatsu, Tetrahedron, 1997, 53, 9965.
6. As a control experiment, the reaction of the tris(2,6-dimethoxyphenyl)methyl radical (ref. 7) and C₆₀ was examined under the same conditions as above. As expected from the oxidation potential of this radical (–20.49 V vs. Fc/Fc+ in PhCN), which is more positive than the first reduction potential of C₆₀, no reaction was observed.
7. M. J. Sabacky, C. S. Johnson, Jr., R. G. Smith, H. S. Gutowsky and J. C. Martin, J. Am. Chem. Soc., 1967, 89, 2054.
8. T. Tanaka, T. Kitagawa, K. Komatsu and K. Takeuchi, J. Am. Chem. Soc., 1997, 119, 9313; K. Takeuchi, T. Kitagawa, A. Miyabo, H. Hori and K. Komatsu, J. Org. Chem., 1993, 58, 5802; K. Komatsu, H. Akamatsu, S. Aonuma, Y. Jinbu, N. Maekawa and K. Takeuchi, Tetrahedron, 1991, 47, 6951; K. Okamoto, T. Kitagawa, K. Takeuchi, K. Komatsu, T. Kinoshita, S. Aonuma, M. Nagai and A. Miyabo, J. Org. Chem., 1990, 55, 996.
9. R. J. Goldacre and J. N. Phillips, J. Chem. Soc., 1949, 1724.
10. M. E. Niyazymbetov, D. H. Evans, S. A. Lerke, P. A. Cahill and C. C. Henderson, J. Phys. Chem., 1994, 98, 13 093; D. E. Cliffel and A. J. Bard, J. Phys. Chem., 1994, 98, 8140.
11. E. Weitz, L. Müller and K. Dinges, Chem. Ber., 1952, 85, 878.
12. An EPR spectrum of a hexane solution of 1·(1.1 × 10^–3 M), which exhibited a signal intensity corresponding to 90 ± 10% of the theoretical value, confirmed the absence of any significant dimerization.
13. Calc. for C₈₅H₃₀N₃: C, 93.39; H, 2.77; N, 3.84. Found for the freshly prepared salt: C, 90.01; H, 2.23; N, 3.50%. Although the C, H, N values are close to the expected values, the total of these elements was only 96%, suggesting a reaction with molecular oxygen and/or water during the analysis.
14. R. Subramanian, P. Boulas, M. N. Vijayashree, F. D'Souza, M. T. Jones and K. M. Kadish, J. Chem. Soc., Chem. Commun., 1994, 1847; D. Dubois, M. T. Jones and K. M. Kadish, J. Am. Chem. Soc., 1992, 114, 6446; P.-M. Allemand, G. Srdanov, A. Koch, K. Khemani, F. Wudl, Y. Rubin, F. Diederich, M. M. Alvarez, S. J. Anz and R. L. Whetten, J. Am. Chem. Soc., 1991, 113, 2780.
15. (a) M. M. Khaled, R. T. Carlin, P. C. Trulove, G. R. Eaton and S. S. Eaton, J. Am. Chem. Soc., 1994, 116, 3465; (b) J. Stinchcombe, A. Pénicaud, P. Bhyrappa, P. D. W. Boyd and C. A. Reed, J. Am. Chem. Soc., 1993, 115, 5212; (c) A. J. Schell-Sorokin, F. Mehran, G. R. Eaton, S. S. Eaton, A. Viehbeck, T. R. O'Toole and C. A. Brown, Chem. Phys. Lett., 1992, 195, 225.
16. J. R. Morton, K. F. Preston, P. J. Krusic, S. A. Hill and E. Wasserman, J. Am. Chem. Soc., 1992, 114, 5454.
17. T. Kato, T. Kodama and T. Shida, Chem. Phys. Lett., 1993, 205, 405; G. A. Heath, J. E. McGrady and R. L. Martin, J. Chem. Soc., Chem. Commun., 1992, 1272; D. R. Lawson, D. L. Feldheim, C. A. Foss, P. K. Dorhout, C. M. Elliott, C. R. Martin and B. Parkinson, J. Electrochem. Soc., 1992, 139, L68.
18. Trace amounts of water in THF may also cause partial hydrolysis, which gives rise to 1–OH. However, the 1:1 ratio would be retained, since the same amount of C₆₀·– would be converted to HC₆₀–C₆₀H. 1–OH and HC₆₀–C₆₀H would be expected to have only a weak (ε < 10³) absorption at wavelengths above 500 nm.