Density functional theory study on the effect of substitution and ring annelation to the rim of corannulene.

B3LYP/6-311G calculations indicate that annelation of a five-membered ring to the rim of corannulene and substitution to all the rim carbons lowers the barrier for bowl-to-bowl inversion. Singlet-triplet energy differences, frontier orbital analysis, and nucleus-independent chemical shift (NICS) values indicate significant enhancement of the reactivity when the substitutions involve exocyclic double bonds. Bowl-to-bowl inversion barrier, curvature, and reactivity for unsaturated and saturated five-membered ring-annelated corannulenes are analogous to decamethyl- and decamethylene-substituted corannulenes.