Nanographene Metallaprisms: Structure, Stimulated Transformation, and Emission Enhancement.

Nanographenes are inclined to assemble into stacked columnar structures that are stabilized by π-π interactions, whereas other supramolecular structures of nanographenes, such as prisms and cages, are rarely investigated. Herein, a diazananographene was synthesized, and then assembled with a coordination unit, thereby producing a triangular metallaprism. After adding C 60 or C 70 , the triangular metallaprism was transformed into a square tetramer, which encapsulated a pair of C 60 or C 70 molecules. The formed host-guest complex demonstrated efficient energy transfer from the diazananographene shell to the C 60 cores. The emission intensity of the capsulated C 60 was enhanced remarkably, compared with free C 60 , due to an increased quantum yield and optical absorption coefficient. This work demonstrates the versatility of nanographene-based supramolecular architectures beyond columnar stacking and their ability to enhance the emission of otherwise non-emissive fullerene.