Theoretical 13C NMR chemical shifts of the stable isomers of fullerene C90

Density functional theory has been employed to study fullerene C-90. Structures of all 46 IPR isomers were optimized at the B3LYP/STO-3G level. Geometry optimization for those isomers with relative energies less than 25 kcal/mol were performed using basis sets up to 6-31G. and the C-13 NMR chemical shifts were calculated using the GIAO method. Isomer 45 is the most stable species, while other stable isomers include 28, 30, 32, 35, 40 and 46. Comparison between prediction and experiment shows that the reported NMR spectrum likely arises from isomers 35 and 46 instead of isomer 36 and one C-2 isomer. (C) 2003 Elsevier Science B.V. All rights reserved.