Remote optical chirality transfer via helical polyaromatic capsules upon encapsulation

Abstract

Helical molecular assemblies have been widely created so far, taking inspiration from helical bioconstructs (e.g., DNAs and proteins). However, the host utilities of such synthetic helices remain largely underdeveloped, particularly as chiroptical nanotools. Here, we report the preparation of new polyaromatic capsules with right- or left-handed quadruple helicity, regulated by chiral saccharide-based side chains attached at the outer surface. The capsule quantitatively encapsulates achiral fluorescent dyes in the cavity. The resultant host-guest complexes display excellent circularly polarized luminescence properties (up to |g_lum| = 1.6 × 10⁻²) derived from the bound dyes, through efficient optical chirality transfer from the outer biochiral groups to the inner achiral dyes via the quadruple helical shell, which represents an unprecedented chiroptical strategy. This nanotool can be applied to spherical fullerene to induce its chirality with high efficiency in solution (up to |g_abs| = 1.0 × 10⁻²) and in the solid state.