Chiral toroids and tendril superstructures from integrated ternary species with consecutively tunable supramolecular chirality and circularly polarized luminescence

Abstract

Many plant tendrils coil into helices which further exhibit terminal-spiral behavior in toroids. In this work, we illustrate the occurrence of such behavior at nano- and microscales whereby nanohelices feature tendril coil-type terminal-cyclization, allowing for the co-existence of toroid-terminated helical superstructures and independent chiral nanotoroids. Multiple-component coassembly was employed to magnify the chirality evolution from the molecular to the macroscopic scale, enabling a consecutively varied supramolecular chirality inversion expressing on Cotton effects, circularly polarized luminescence (CPL) and macroscopic handedness of superstructures. N-Terminal aryl serine derivatives were noncovalently bound to distinct species via charge-transfer and duplex H-bonds, which diminished the unfavorable competitive pathways and facilitated a ternary coassembly route. Hierarchical and modularized coassembly from one to three species witnessed the consecutive chirality inversion, which enabled the flexible chiroptical manipulation including Cotton effects and CPL. Spring-like helices by coassembly demonstrate terminal-spiral behavior, allowing for the formation of heterojunction-like superstructures, which shares a similar process to the tendril coiling. Due to the specific cyclization behavior, the affiliated and independent toroidal structures share identical chirality to helices. Such a ternary coassembly affords a modularized and precise protocol to noncovalently synthesize soft topological structures with fine tailored CPL handedness, dissymmetry factor and luminescent colors.