Bowl-Shaped Indenofluoranthenes: Organoselenium Functionalization and Titanium Coordination

Abstract Indeno[1,2,3-cd]fluoranthene (iFLA) is known as one of the smallest π-segments of fullerene C60. However, its intrinsic chemical reactivity remains largely unexplored. Herein, we report a regioselective 1,4-functionalization of iFLA, affording an ethylene-bridged di(n-butyl)indeno[2,1-a]fluorene derivative (iFL). The crystallographic analysis confirmed the bowl-shaped geometry. The further oxidation of the ethylene bridge by benzeneseleninic anhydride (PhSeO)2O provided the corresponding diketone together with an elusive intermediate bearing an organoselenium functionality. This provides mechanistic insights into the (PhSeO)2O-mediated oxidation process. The diketone was further converted in situ into an N,N-chelating di(imino) ligand to generate a 12-electron octahedral coordinate d0-complex through a one-pot protocol. These methods would be applicable to diversify fullerene-inspired π-segments with functional groups containing main group elements.