Construction of Chiral Nanoassemblies Based on Host-Guest Complexes and Their Responsive CD and CPL Properties: Chirality Transfer From 2,6-helic[6]arenes to a Stilbazolium Derivative.

A couple of water-soluble chiral 2,6-helic[6]arene derivatives - and - were synthesized, and they could form 1:1 stable complexes with 4-[(4'--diphenylamino)-styryl]--methylpyridinium iodide () in water. Compared with , the host-guest complexes exhibited enhanced fluorescence, which might be attributed to the spatial confinement of and restriction of aggregation-caused quenching (ACQ) effects. Based on the host-guest complexation, the first helic[6]arene-based chiral assemblies were then constructed, and they showed rectangular or hexagonal nanostructures by scanning electron microscopy (SEM) images. Interestingly, the assemblies showed clear mirror-image circular dichroism (CD) and circularly polarized luminescence (CPL) spectra in aqueous solution, revealing a consecutive chirality transfer from the chiral macrocyclic cavities of the hosts to . Moreover, the supramolecular chirality of the assemblies could also show responsiveness to the pH values and temperatures of the system.