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 C₆₀ or C₇₀ , the triangular metallaprism was transformed into a square tetramer, which encapsulated a pair of C₆₀ or C₇₀ molecules. The formed host-guest complex demonstrated efficient energy transfer from the diazananographene shell to the C₆₀ cores. The emission intensity of the capsulated C₆₀ was enhanced remarkably, compared with free C₆₀ , 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.