J. Phys. Chem. 1992, 96,8317-8325 (54) Alcami, M.; MI, 0.; YBRez, M.; Abboud, J.-L. M. J . Phys. Org. Chem. 1990,4, 177. (55) V. G. Analytical Ltd.; Wythenshawe, Manchester, G.E., Britain. (56) C w h , R. G.; Beynon, J. H.; Caprioli, R. M.; Lester, G. R. Metosrable Ions; Elsevier: New York, 1973. (57) Lias, S.G.; Liebman, J. F.; Levin, R. D. J. Phys. Chem. Ref Data 1984, 13. 695. Lias, S. G.; Bartmess, J. E.; Liebman, J. F.; Holmes, J. L.; Levin, R. D.; Mallard, W. G. J . Phys. Chem. ReJ Data 1988, 17, 1 . (58) N o h , R. H.; Rodwell, W. R.; Bouma, W. J.; Radom, L. J. Am. Chem. Soc. 1981, 103, 1913. (59) Nguyen, N. T.; Hegarty, A. F.; Ha, T.; DeMare, G. R. J . Chem. Soc., Perkin Trans. 2 1986, 147. (60) Sodupe, M.; Bauschlicher, C. W., Jr. Chem. Phys. Lett. 1991, 181, 321.
8317
(61) Alcad, M.; M6,O.; YiIRez, M.; Abboud, J.-L. M.; Elguero, J. Chem. Phys. Lett. 1990, 172, 471. (62) Ford, G. P.; Smith, C. T. J . Am. Chem. Soc. 1987, 109, 1325. (63) Yamamoto, S.;Bach, R. A. Can. J . Chem. 1985, 63, 549. (64) Smith, B. J.; Nguyen, M. T.; Bouma, W. J.; Radom, L. J . Am. Chem. Soc. 1991, 113, 6452. (65) Weber, M. E.; Elkind, J. L.; Armentrout, P. B. J. Chem. Phys. 1986, 84, 1521. (66) Yaoming, X.; Yates, B. F.; Yamamuchi, Y.; Schaefer H.F., 111 J. Am. Chem. SOC.1989,111, 6163. (67) Burgers, P. C.;Terlow, J. K.; Holmes, J. L. Org. Mass Spectrom. 1982, I?, 369. (68) Bowen, R. D.; Williams, D. H.; Hvistendahl, G. J . Am. Chem. Soc. 1977, 99, 7059.
Semiempirical Calculations of C60Derivatives: Addition to Double Bonds Radiating from a Five-Membered Ring+ Nobuyuki Matsuzawa,t David A. Dixon,* and Paul J. Krusic The Central Research and Development Department, E. I. Du Pont de Nemours & Co. (Inc.),Experimental Station, P.O. Box 80328, Wilmington, Delaware 19880-0328 (Received: February 27, 1992)
The electronic structures of CWderivatives with one to five atoms added at adjacent double bonds radiating from a fivemembered ring have been calculated with the PM-3 parametrization of the MNDO Hamiltonian. The calculations were done for n = 1 4 with H, F, and C1 and for n = 5 with H. The stabilities of the Ca derivatives are predicted from the calculated energies. The isodesmic reactions of C a with alkanes and perchloroalkanes are predicted to become more exothermic with increase in the number of substituents and the length of the alkyl chain. The reactions of Cm with perfluoroalkanes are not predicted to be exothermic due to the stable C-F bond in perfluoroalkanes. Valence bond structures are presented on the basis of the calculated geometries and spin densities. These results are compared to ESR measurements.
1. Introduction Buckminsterfullerene (C,) was initially observed as a mass peak in a carbon cluster beam.' The authors proposed that the Cbopeak corresponded to a cation derived from a c60 structure of a truncated icosahedron (I, symmetry). Subsequently, a significant amount of work2on Ca as well as C70 was done, but no macroscopic amounts of the molecules were isolated. Krihchmer et al.) developed a method for preparing macroscopic amounts of the fullerenes, allowing these new forms of carbon clusters, especially C,, to be studied by traditional chemical methods. Many different experiments including infrared3 and Raman4 spectroscopy, NMR: scanning tunneling microscopy! and X-ray diffractionaChave been done to support and c o n f i i the proposed icosahedral structure of C., Presently, new results on c60, C70, and other fullerenes are published weekly. OnIy a few derivatives of C, have b a n reported, for example, the complex of Cbowith metals7v8such as the C60-Os04r7P9b the Cso-platinumcomplex,'M and a variety of doped systems including boron? alkalis,'OJ' and transition metals.I2 Derivatives of the fullerenes will be an important area of research in terms of potential applications and the discovery of new properties. Hydrogenation of Cm via Birch reduction has been shown to yield CboH3&I3Fluorination of Cboand C70 has been reported,14 and the formation of CboF36,C7oF40, and other fluorinated Cm's and C7
