Stabilization of conformational chirality and reprogramming of excited states in a molecular cage via post-synthetic...

Chirality can spontaneously emerge in three-dimensional architectures assembled from achiral precursors, such as molecular cages. However, this conformational chirality is often labile, which limits its utility in chiroptical applications. Here, we report a post-synthetic BF₂ locking strategy that simultaneously suppresses enantiomeric interconversion and reprograms the excited-state electronic structure of a molecular cage. This modification endows the cage with persistent chirality and circularly polarized luminescence (CPL), while reducing the singlet-triplet energy gap from 317 to 165 meV, thereby enabling efficient thermally activated delayed fluorescence (TADF). Our work establishes post-synthetic locking as a versatile strategy for decoupling cage construction from the subsequent optimization of chiroptical and photophysical properties, while retaining the opportunity for post-synthetic electronic tuning.