Synthesis of Fullerene-Fluorene Dyads through the Platinum-Catalyzed Reactions of [60]Fullerene with 9-Ethynyl-9-fluoren-9-yl Carboxylates.

The single-step regio- and stereoselective platinum-catalyzed reactions of [60]fullerene with a series of 9-ethynyl-9-fluoren-9-yl carboxylates afforded fullerene-fluorene dyads in their [2 + 2] cycloaddition forms. The presented reactions represent the first examples of the use of easily accessible fluorenyl carboxylates as fluorenylideneallene precursors. In addition, the single-crystal X-ray structure of one of the dyads reveals a distorted cyclobutane ring. Furthermore, the dyad forms a layered structure with close-packed arrays of C spheres in its crystals.