C60(NO2)2: Quantum-Chemical Evaluations of Structure, Energetics, and Vibrational Spectra

Abstract The complete PM3 structural optimizations are reported for all 23 positional isomers of C60(NO2)2 and interesting symmetry reductions are found. There are two low energy structures while all the remaining species are separated by more than 10 kcal/mol from the computed ground state. In the ground state the two nitro groups are placed in para position on one hexagon. The next lowest structure is produced by addition to one 6/6 (double) bond of the cage. The species highest in energy are separated by more than 50 kcal/mol from the ground state. IR vibrational spectra are also predicted for the low-energy structures.