Most stable structure of fullerene and its novel activity toward addition of alkene: A theoretical study
- 化学化工－已发表论文 
Structures and stabilities of fullerene C-20 and C-20(-) have been investigated by the density functional theory and CCSD(T) calculations. In consideration of the Jahn-Teller distortion of I-h-symmetric C-20, possible subgroup symmetries have been used in the full geometry optimization. On the basis of relative energetics, vibrational analyses, and electron affinities, fullerenes C-20 and C-20(-) have most stable D-2h and C-i structures, respectively. The controversy on the relative stability of fullerene arises from the use of different subgroups in calculation and the basis set dependence in vibrational analysis. Predicted nucleus-independent chemical shift values show that the most stable fullerene C-20 and its derivatives C-20(C2H2)(n) and C-20(C2H4)(n) (n=1-3) exhibit remarkable aromaticity, while C-20(C2H2)(4) and C-20(C2H4)(4) have no spherical aromaticity. The C-20 (D-2h) cage has remarkable activity toward the addition of olefin, and such feasibility of the addition reaction is ascribed to strong bonding interactions among frontier molecular orbitals from C-20 and olefin. Calculations indicate that both C-20(C2H2)(n) and C-20(C2H4)(n) have similar features in electronic spectra. (c) 2007 American Institute of Physics.