Rational Design of Chiral Single-Benzene-Based Fluorophores via Enantioselective Twofold C−H Activation: Solid-State and Circular Polarization Luminescence, and Cellular Imaging Application

Abstract

Developing chiral materials remains highly challenging due to the limited synthetic approaches to achieve enantiopure molecules with harmoniously optoelectronic properties. Herein, a class of chiral single-benzene-based fluorophores with new backbone was demonstrated via Rh-catalyzed twofold and enantioselective C–H activation with chiral transient directing group strategy. It not only approaches an efficient protocol of enantioselective twofold C–H activation in one-pot with single catalytic system, but also achieves a class of novel chiral single-benzene-based fluorophores. The new chiral fluorophores showed favorable photophysical properties, including large Stokes shifts, good fluorescence quantum yields, aggregation-induced emission (AIE) in aqueous solution, and intense emission and circularly polarized luminescence (CPL) in the solid state, indicating great potential applications as chiral fluorescent probes or optoelectronic materials. Further examination of photophysical properties and computational calculation exhibited a crucial role of the rigidly five-membered ring to provide good fluorescence quantum yields. In addition, 3al and 3aowere also employed as representatives for the lipid droplet-targeting bioimaging in living cells.