Synthesis and Properties of Monosubstituted Ethynylcorannulenes

The solution-phase synthesis of corannulene has been modified and it is now possible to prepare multi gram quantities of corannulene more efficiently, with considerably less toxic reagents. Cross-coupling of bromocorannulene with TMS-acetylene and phenylacetylene affords novel ethynyl-containing corannulene derivatives. Deprotection of TMS-ethynyl corannulene affords the naked alkyne, which can be cross-coupled with pentafluoroiodobenzene and bromocorannulene to afford the appropriate alkyne derivatives. The photophysical properties of this new and novel family of alkyne-containing corannulene derivatives has been evaluated and all of the new derivatives exhibit low to moderate quantum efficiencies.