Theoretical evidence for the major isomers of fullerene C84 based on 13C NMR chemical shifts

Abstract

Geometry optimizations for three isomers of fullerene C₈₄, 21, 22 and 23, have been performed by density functional theory (DFT) at the B3LYP/6-31G* level of theory. ¹³C NMR chemical shifts were evaluated by the GIAO method employing 6-31G* and 6-311G** basis sets. Isomers 22 and 23 are predicted to have essentially equal energies and isomer 21 to be 16 kcal mol⁻¹ less stable. The calculated ¹³C NMR chemical shifts of isomers 22 and 23 agree nicely with experimental data while the results of isomer 21 show large differences, indicating that isomer 22 is the experimentally observed D₂ isomer.