Structures and Electronic Properties of C 56 Cl 8 and C 56 Cl 10 Fullerene Compounds

Stimulated by the recent observation of the first C 56 Cl 10 chlorofullerene ( Science , 2004 , 304 , 699), we performed a systematic density functional study of the structures and properties of C 56 Cl 10 and related compounds. The fullerene derivatives C 56 Cl 8 and C 56 Cl 10 based on the parent fullerene C 56 ( C 2v :011), rather than those from the most stable C 56 isomer with D 2 symmetry, are predicted to possess the lowest energies, and they are highly aromatic. Further investigations show that the heats of formation of the C 56 Cl 8 and C 56 Cl 10 fullerene derivatives are highly exothermic, that is, −48.59 and −48.89 kcal mol −1 per Cl 2 (approaching that of C 50 Cl 10 ), suggesting that adding eight (or ten) Cl atoms releases much of the strain of pure C 56 ( C 2v :011) fullerene and leads to highly stable derivatives. In addition, C 56 Cl 8 and C 56 Cl 10 possess large vertical electron affinities, especially for C 56 Cl 8 with value of 3.20 eV, which is even larger than that (3.04 eV) of C 50 Cl 10 , indicating that they are potential good electron acceptors with possible photonic/photovoltaic applications. Finally, the 13 C NMR chemical shifts and infrared spectra of C 56 Cl 8 and C 56 Cl 10 are simulated to facilitate future experimental identification.