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J. Am. Chem. Soc. 1995, 117. 7003-7004
Communications to the Editor There Is a Hole in M y Bucky Jan C. Hummelen.' Maurizio Pra1o.j and Fred Wudl*.' Iitrrirure for Polymers and Organic Solid.7
Depurrmenr af CItemisr~und Phjsics Univer.vin uf Califomin. Sanra Barbara Sunto Burhura. California 93106 Dipanimenro di Scienx Farmaceuriche Piarzale Europu I . 34127 Trierre, Ira/? Received April 12, 1995 From the heginning. the discovery of CN) and the other fullerenes has ignited the imagination of many scientists. in particular those working in supramolecular chemistry. These carhon cages are the simplest hollow structures which might give rise to interesting host-guest complexes with potential applications that would include complexation. catalysis. constrictive binding. and protection of unstahle species.' The first examples of endohedral metallofullerenes were prepared in 1991 with a high-temperature laser vaporization method.' The preferred way to prepare endohedral complexes has heen the carhon arc burning method using mixtures of graphite and the guest-to-be materials in composite rods.' Nohle gases can alsn he forced into the cages by high-temperaturehigh-pressure conditions.' The yields of endohedral complexes in these reactions are very low. and separation from the hollow fullerenes for purification of the desired products has heen a major prohlem. The above-mentioned methods are not likely to he suitable for the encapsulation of small molecules as well as molecular and atomic ions. Another approach io endohedral complexes would comprise controlled opening of the fullerene. encapsulation of the guest material. and restoration of the original fullerene structure, a strategy that Hawkins very likely considered in his pioneering work on osmylation of Cw and C70.4.~Hydrolysis of the osmate esters apparently did not afford the diol. and this approach failed. Here we repon the first regioselective and efficient synthetic method for severing two adjacent honds in Cmh Reaction of CN)with azides yields [5.6]azafulleroids in good yields.' In the azafulleroid. one C-C bond is cleaved (see 1). and the C=C honds adjacent to the nitrogen atom are susceptible to regiospecific formation of hisazafulleroids.x The previously reponed elegant work on the self-sensitized photooxygenation of cenain CHI adducts.' was applied to N-methoxyethoxymethyl (MEM)-substituted [5.6]azafulleroid 1I
i
' Univenity of Califomia. Santa Barbara.
: Dipanimunto di Scicnzc Farmaceutiche. I I I Cr;m. D. I.: Cram. J. M . Cmroinrr Molecdei and Their Gurrrr; The Ra!.;il S w i n y of Chemistry: Camhridpe. 1994.
1?1Chilt. Y.:Guo, T.: Jin. C.: Haufler. R. E.: Chihante. L. P. F.; Fure. I.: Wmg. L.: Alford, J . M.: Smalley. R. E. J. P I I W Chmi. 1991. 95. 7564 131 Ssundcr\. M.: Jim6nei-Vi)iquei. H. A,: Cross. R. I.: Poreda. R. I. S c i m w 1993. 259. 1428. I41 Hankin$. I . M.: Mleyer. A,: Solow. M. A. J . Am. Clwm Sor. 1993. , I C ,1111, .,.,.
lS)H;wkin\. J. M.: Meyer. A. Science 1993. 260. 1918.
161,\ nompcific oxidative duster opening was reponed: Taliani. C.: Ruiint. G.: Zimhmi. R.: Danieli. R.: Rossmi. S.: Denisor.. V. M.:Burk. V. \I.: Burlakav. F.: Seeri. G.: Orlandi. F.: Zerhetto. X. J . Clwm. Sor.. Chrm. C,",,,,. 1993. ZZO: 171 PTXO.hl.: Li. 0.: Wudl. F.: Lucchini. V. J. Am. Clzem. SOC. 1993. IlS, Il4X. lXlGnir\er. T.: Prato. M.: Lucchini. V.: Hinch. A,: Wudl. F. An,qrw
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