Theoretical 13C NMR spectra of IPR isomers of fullerene C80: a density functional theory study

Optimized geometries and 13C NMR chemical shifts of fullerene C80 have been calculated by density functional theory using B3LYP/6-31G* for all isolated-pentagon-rule isomers with non-zero HOMO–LOMO gap (isomers 1, 2, 3, 4 and 5). D2 distorted isomer 7 is predicted as first-order saddle-point by B3LYP/STO-3G. The calculated NMR spectrum of isomer 2 agrees well with experiment of Hennrich, confirming the assignment unequivocally. The predicted spectra of other isomers either show unusually large spectral span or have unusual chemical shifts for some sites, indicating unfavorable electron distribution. Both energetic and NMR properties indicate these isomers are less stable than isomer 2.