Buckybowls. Synthesis and ab initio calculated structure of the first semibuckminsterfullerene
- Louisiana State Univ., Baton Rouge, LA (United States)
This report describes the first synthesis and characterization of a C{sub 30} hydrocarbon (4) whose carbon framework represents half of the buckminster-fullerene C{sub 60} surface. Such C{sub 30} structures represent a new class of compounds referred to as semibuckminster-fullerenes. These hydrocarbons share common characteristics: (a) 30 sp{sup 2} carbon frameworks, consisting of multiple fused five- and six-membered rings, that may be identified on the buckminster-fullerene surface, and (b) bowl-shaped geometries. Semibuckminster-fullerenes have been regarded as attractive synthetic targets as potential intermediates in a `classical` total synthesis of C{sub 60}. However, despite these efforts, the semibuckminster-fullerenes have heretofore remained elusive. Our synthesis of 4 was accomplished in a manner analogous to the Scott procedure for the preparation of corannulene 2 except that the recently synthesized 1,2,5,6-tetraoxopyracene served as the starting material. A remarkable quadruple ring closure was required during the flash vacuum pyrolysis step. Surprisingly, the latter pyrolysis proceeded rather smoothly, yielding essentially a single product by GC-MS; 4 was purified by chromatography and was characterized spectroscopically. {sup 1}H NMR showed the expected AB multiplet plus a singlet in the ratio 2:1, and {sup 13}C NMR exhibited three methine carbons and five quaternary carbons. 20 refs., 1 fig.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 102768
- Journal Information:
- Journal of the American Chemical Society, Vol. 116, Issue 17; Other Information: PBD: 24 Aug 1994
- Country of Publication:
- United States
- Language:
- English
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