Lowering inversion barriers of buckybowls by benzannelation of the rim:: Synthesis and crystal and molecular structure of 1 2-dihydrocyclopenta[b,c]dibenzo[g,m]corannulene

[GRAPHICS] 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 H-1 NMR experiments.