Investigation on stabilities and spectroscopy of C 80 O 2 based on C 80 ( D 5 d ) using density functional theory

The relative stabilities of the 17 possible isomers for C 80 O 2 based on C 80 ( D 5 d ) were studied using Becke three parameters plus Lee, Yang, and Parr's (B3LYP) method and 6‐31G (d) basis set in density functional theory. The most stable geometry of C 80 O 2 was predicted to be 23,24,27,28‐C 80 O 2 (A) with annulene‐like structures, where the additive bonds are those between two hexagons (6/6 bonds) near the equatorial belt of C 80 ( D 5 d ). Electronic spectra of C 80 O 2 isomers were calculated based on the optimized geometries using intermediate neglect of differential overlap (INDO) calculation. Compared with those of C 80 ( D 5 d ), the first absorptions in the electronic spectra of C 80 O 2 are blue‐shifted owing to the wide energy gaps. 13 C nuclear magnetic resonance spectra and nucleus independent chemical shifts of the C 80 O 2 isomers were computed at B3LYP/6‐31G level. The chemical shifts of the bridged carbon atoms in the epoxy structures of C 80 O 2 compared with those of the bridged carbon atoms in the annulene‐like structures are changed upfield. Generally, the isomers with the annulene‐like structures of C 80 O 2 are more aromatic than those with the epoxy structures. The addition of the oxygen atoms near the pole of C 80 ( D 5 d ) is favorable to improving the aromaticities of C 80 O 2 . © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009