Supramolecular Nanohelix Fabricated by Pillararene-Based Host-Guest System for Chirality Amplification, Transfer, and Circularly Polarized Luminescence in Water

Amplified chirality and Förster resonance energy transfer (FRET)-assisted chirality transfer from molecular to nanoscale level have been shown to play a vital role in co-assembled nanohelix for potential energy transfer in biological systems. Herein, we have constructed a chiral host-guest complex donor system for chiral amplification via induced chirality of pillar[5] arene host and loaded it with an achiral dye acceptor to demonstrate how chirality-assisted excitation energy transfer occurred in the supramolecular nanohelix system in an aqueous medium. We found that the individual chiral copolymeric guest could self-assemble into nanohelixes. In the presence of pillar[5]arene host, the formed supramolecular host-guest complex also proceeded to form long helical fibers via J-aggregation of pillar[5]arene; thus, causing amplified chirality. After loading an achiral dye acceptor into the host-guest complex donor, it achieved co-assembled composite nanohelixes via electrostatic interactions and ordered stacking of the chromophoric dyes. In this hybrid supramolecular system, the loaded dye was uniformly dispersed, becoming the driving force for chirality transfer. Fascinatingly, this supramolecular system containing achiral dye could capture both chiral information and energy from the chiral donor, displaying supramolecular chirality and FRET-assisted amplified circularly polarized luminescence (CPL) in water with a large dissymmetry factor (g_lum = 1.32 × 10⁻²).