Relative energies of isomers of C36F2

The symmetry unrestricted C36F2 isomers formed from fullerene C-36, the ini tial symmetry of which is C-6v, C-6h, or D-2d, have been extensively studie d with semi-empirical (AM1 and PM3) calculations. Based on the relationship between the isomer's stability and the adding positions, three patterns of the adding sites of F-2 moiety in the additive reactions have been deducte d. The results of the pi -orbital axis vector (POAV) analysis indicate that the chemical reactivity of C-36 is the result of the high strain in the C- 36 cage. But, in order to form stable compounds, the effects, which guide t he F-2 moiety to select carbon atoms in the C-36 cage, are dominated by the conjugate effect in C36F2 system rather than the strain release in the C-3 6 cage. (C) 2001 Elsevier Science B.V. All rights reserved.