Supramolecular Assembly of Edge Functionalized Top-Down Chiral Graphene Quantum Dots

Dedicated to Prof. Miguel A. Alario on the occasion of his 80(th) birthday The construction of supramolecular assemblies of heterogeneous materials at the nanoscale is an open challenge in science. Herein, new chiral graphene quantum dots (GQDs) prepared by amidation reaction introducing chiral amide groups and pyrene moieties into the periphery of GQDs are described. The analytical and spectroscopic data show an efficient chemical functionalization and the morphological study of the supramolecular ensembles using SEM and AFM microscopies reveals the presence of highly ordered fibers of several micrometers length. Fluorescence studies, using emission spectroscopy and confocal microscopy, reveal that the fibers stem from the pi-pi stacking of both pyrenes and GQDs, together with the hydrogen bonding interactions of the amide groups. Circular dichroism analysis supports the chiral nature of the supramolecular aggregates.