Synthesis of Highly Luminescent Chiral Macrocyclic Molecular Carbon Imides

We report the synthesis of racemic macrocyclic molecular
carbon
imides, (±)-C[2]BNDI and (±)-C[3]BNDI, using 1,1′-bi(naphthyl-4,5-dicarboximides) (BNDI) as a building block. Single-crystal analysis revealed a twisted
saddle-shaped π-framework for (±)-C[2]BNDI. Both macrocycles exhibit strong emission, with (±)-C[2]BNDI showing strong fluorescence (quantum yield = 100%) in nonpolar solvents.
After chiral resolution, enantiopure (+)- and (−)-C[2]BNDI is found to exhibit a |glum| value of
3.3 × 10–3 and a high CPL brightness of 63.9
M–1cm–1. This study introduces
a new class of chiral conjugated macrocycles with outstanding luminescent
and chiroptical properties, offering promising opportunities for future
applications in photonic and optoelectronic materials.