Achieving Chiral Recognition of Fluorophores Through Förster Resonance Energy Transfer

Most conventional methods for molecular chiral recognition require dissolution in solvents, which often compromises recognition accuracy due to solvent-induced perturbations. Therefore, developing a rapid and solvent-free strategy for chiral discrimination is of great importance. Here, we present a chirality-dependent Förster resonance energy transfer (FRET) system for enantiomer recognition in the solid state. Perylene diimide (PDI) enantiomers serve as fluorescent selectands (guests), while chiral naphthalimide (NMI) or naphthalene diimide (NDI) act as chiral selectors (hosts). Photophysical studies reveal that host and guest with homochirality exhibit markedly enhanced fluorescence compared to heterochiral counterparts, attributed to more efficient FRET. In contrast, control experiments under FRET-suppressed conditions fail to effectively discern molecular chirality. Molecular dynamics simulations reveal that homochiral host and guest tend to adopt more compact molecular packing, thereby promoting FRET. This work provides a noncovalent fluorescence-based platform for real-time enantioselective recognition in the solid state.