Self-Assembly and Nonlinear Optical Properties of N-Substituted Fulleropyrrolidine Bearing Adamantane

Bearing a highly symmetric and rigid structure, fullerene C60 is a fascinating building block in supramolecular chemistry. The fact that the C60 moiety can be chemically modified brings infinite possibility in fine tuning the self-assembled structures. Herein, we report the synthesis of an N-substituted fulleropyrrolidine bearing adamantane (Ad) where the Ad unit was anchored onto the C60 moiety through only one-step reaction. Self-assembly of the Ad-C60 hybrid was investigated via a modified liquid-liquid interfacial precipitation (LLIP) method. Superstructures with rich morphologies were obtained, including spheres, hexagons, cubes, flowers and stacked flakes. Self-assemblies from xylene systems were selected as examples for deeper investigation. The internal organization was probed by power X-ray diffraction, which confirms the formation of monoclinic and orthorhombic lattice. Measurements on nonlinear optical performance revealed reverse saturable absorption. The photoluminescence of the Ad-C60 hybrid, both in solution and in the crystalline form, was also discussed with close comparison to two of its monosubstituted counterparts. This work provides insight on the structureproperty relationship of the C60-based superstructures, and strengthens the charming feature of C60 in both supramolecular chemistry and material science.