Luminescent chiral molecular glasses by melt-quenching enantiopure BINAP

Chiral organic glasses combine unique optical properties with processing advantages of amorphous solids. Here, we demonstrate melt-quenching as a strategy for preparing optically active glasses from enantiopure BINAP (2,2’-bis(diphenylphosphino)-1,1’-binaphthyl), a pivotal ligand for luminescent metal complexes and in asymmetric catalysis. Thermal characterisation reveals that only R-BINAP and S-BINAP, not rac-BINAP, form molecular glasses with glass transition temperatures near 100 °C. Pair distribution function analysis and circular dichroism confirm the retention of local structure and homochirality despite disrupted long-range order. Remarkably, the glassy state has a beneficial influence on the molecular optoelectronic properties in comparison to the crystalline state, resulting in an enhancement of the radiative rate constant by 50% due to more favourable Franck-Condon factors. In addition, a highly unusual simultaneous improvement of circularly polarized luminescence (CPL) by nearly an order of magnitude is observed, achieving dissymmetry factors |glum| approaching 10–2 that are comparable with the top-performing purely organic molecular chiral emitters reported to date. These findings establish melt-quenched chiral molecular glasses as promising platforms for advanced optoelectronic and photonic materials, combining exceptional chiroptical properties, strong luminescence, and processability without the constraints of crystallinity.