Lowering Inversion Barriers of Buckybowls by Benzannelation of the Rim:  Synthesis and Crystal and Molecular Structure of 1,2-Dihydrocyclopenta[<i>b</i>,<i>c</i>]dibenzo[<i>g</i>,<i>m</i>]corannulene

Abstract

[structure: see text]. The title compound (3) has been synthesized by a non-pyrolytic route providing a 36% isolated yield in the final step. X-ray crystal structure determination shows that 3 crystallizes with one solvating molecule of toluene and exhibits slightly lower curvature than the parent cyclopentacorannulene. DFT calculations predict a substantially lower bowl-to-bowl inversion barrier for 3 than for dihydro-cyclopentacorannulene, and this is confirmed by dynamic 1H NMR experiments.