Endohedral fullerene

"[2] The choice of the symbol has been explained by the authors as being concise, readily printed and transmitted electronically (the at sign is included in ASCII, which most modern character encoding schemes are based on), and the visual aspects suggesting the structure of an endohedral fullerene.

Aside from the dominant presence of mono-metal cages, numerous di-metal endohedral complexes and the tri-metal carbide fullerenes like Sc3C2@C80 were also isolated.

With the synthesis of the Sc3N@C80 by Harry Dorn and coworkers, the inclusion of a molecule fragment in a fullerene cage had succeeded for the first time.

The lack of reactivity in Diels-Alder reactions is utilised in a method to purify [C80]−6 compounds from a complex mixture of empty and partly filled fullerenes of different cage size.

[4] Since all the six-membered rings in C80-Ih are equal[4] the two encapsulated Ce atoms exhibit a three-dimensional random motion.

It is possible to force the metal atoms to a standstill at the equator as shown by x-ray crystallography when the fullerene is exahedrally functionalized by an electron donation silyl group in a reaction of Ce2@C80 with 1,1,2,2-tetrakis(2,4,6-trimethylphenyl)-1,2-disilirane.

The formation of endohedral complexes with helium, neon, argon, krypton and xenon as well as numerous adducts of the He@C60 compound was also demonstrated[9] with pressures of 3 kbars and incorporation of up to 0.1% of the noble gases.

While noble gases are chemically very inert and commonly exist as individual atoms, this is not the case for nitrogen and phosphorus and so the formation of the endohedral complexes N@C60, N@C70 and P@C60 is more surprising.

Nevertheless, N@C60 is sufficiently stable that exohedral derivatization from the mono- to the hexa adduct of the malonic acid ethyl ester is possible.

Atomic or ion traps are of great interest since particles are present free from (significant) interaction with their environment, allowing unique quantum mechanical phenomena to be explored.

For example, the compression of the atomic wave function as a consequence of the packing in the cage could be observed with ENDOR spectroscopy.

The calculated data allows using C60 fullerene as a Faraday cage,[13] which isolates the encapsulated atom from the external electric field.

[20] As shown theoretically,[21] compression of molecular endofullerenes (e.g., H2@C60) may lead to dissociation of the encapsulated molecules and reaction of their fragments with interiors of the fullerene cage.