Tethered Enantiopure Boramidines for Advanced Chiroptical Studies.

Boramidines are promising chromophores capable of circularly polarized luminescence (CPL). The synthesis, characterization, and photophysical analysis of novel BINOL- and H8-BINOL-tethered boramidines 1 and 2 are reported, leveraging the chiral perturbation strategy for CPL material design. These enantiopure compounds, prepared in a concise three-step synthesis, exhibit high fluorescence quantum yields ϕ (up to 95% in N₂-saturated solutions) and luminescence dissymmetry factors (|glum| ∼ 10- 3). Transient absorption spectroscopy and quantum-chemical calculations provide insight into their singlet-triplet spin-orbit coupling and intersystem crossing mechanisms.