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Transmutation of fullerenes.
R James Cross1, Martin Saunders
1Department of Chemistry, Yale University, PO Box 208107, New Haven, Connecticut 06520-8107, USA. james.cross@yale.edu
Journal of the American Chemical Society
|March 3, 2005
Summary
Pyrolysis of larger fullerenes like C76, C78, and C84 caused carbon loss and smaller fullerene formation. Encapsulated helium in C76 was mostly lost, while C60 remained intact during high-temperature decomposition.
Area of Science:
- Fullerenes chemistry
- High-temperature materials science
Background:
- Fullerenes are allotropes of carbon with unique cage-like structures.
- Understanding fullerene stability under thermal stress is crucial for their applications.
Purpose of the Study:
- To investigate the thermal decomposition pathways of various fullerenes.
- To determine the effect of pyrolysis on fullerene structure and encapsulated species.
Main Methods:
- Sublimation of fullerenes into argon gas.
- Pyrolysis in an oven at approximately 1000°C.
- Analysis of decomposition products and encapsulated helium retention.
Main Results:
- C76, C78, and C84 readily lost carbon atoms, forming smaller fullerenes.
- Isomerization was observed for C78 during pyrolysis.
- Pyrolysis of (3)He@C76 resulted in significant loss of encapsulated helium.
- C60 demonstrated high thermal stability, with no decomposition or helium loss.
Conclusions:
- Larger fullerenes undergo facile carbon extrusion and fragmentation at high temperatures.
- The stability of encapsulated species varies significantly with the fullerene cage size.
- C60 exhibits remarkable thermal resilience, making it suitable for high-temperature environments.