Coassembled Ionic Organic Microcrystals with Bright Circularly Polarized Luminescence

The in situ protonation and crystallization of pyridine-functionalized small molecules 1–3 with enantiopure camphor sulfonic acid afford ionic organic crystals, which exhibit bright blue circularly polarized luminescence (CPL) with high emission quantum efficiencies (Φ: 79–91%) and luminescence dissymmetry factors in the 10–2 order. These crystals are investigated by microscopy, absorption and emission spectral, and powder and single-crystal X-ray diffraction analyses. The chiral optical properties of these microcrystals are examined by circular dichroism and CPL studies. By tuning the substitution position of the pyridine groups, microcrystals with different morphologies and opposite CPL signals are achieved.