Chiral C3-symmetric molecule assembly enabling topological nanotoroid, fused nanotoroid, and nanocatenane

Abstract

Although chiral nanostructures have been extensively studied, the fabrication of topological entities such as toroidal assemblies and their higher-order fused or catenated structures remains a formidable challenge. Here, we demonstrate a hierarchical assembly paradigm using a C3-symmetric benzene-1,3,5-tricarboxamide that enables the topological evolution of varied nanoarchitectures, such as discrete nanotoroids, fused super-nanotoroids containing up to 21 toroidal units, and nano-[2]catenanes. Our experimental and calculation results demonstrated that C3 molecules tended to form helical nanofibers with unexpected curvature due to both molecular chirality and bulky side chains. Further longitudinal extension and lateral lamellar packing of primary one-dimensional stacks led to the formation of dominant nanotoroids and stochastic nano-[2]catenanes with chiroptical signals and circularly polarized luminescence through an adaptive templating method. This work presents a cyclization-driven precise assembly of topologically discrete, fused, and catenated nanotoroids, unveiling the synergistic merging of chiral hierarchy and topological architectures in supramolecular self-assembly systems.