Binaphthyl-Bridged Pyrenophanes: Intense Circularly Polarized Luminescence Based on a D2 Symmetry Strategy

A series of D-2-symmetric macrocycles composed of alternately linked pyrene and binaphthyl moieties (binaphthyl-bridged pyrenophanes) have been synthesized. Among them, a pyrenophane possessing ether linkers at the 2,7-positions of the pyrenes exhibited intense circularly polarized luminescence (CPL) with a |g(lum)| value of 0.053. This value is by far the highest for excimers and was not sensitive to temperature, solvent, or concentration. The CPL originated from a twisting pyrene excimer, with the (R)-binaphthyl moieties producing a left-handed twist excimer, which exhibited (-)-CPL. The electric and magnetic transition dipole moments are perfectly parallel, which is the best relationship for strong CPL.

Automated summary

A series of D-2-symmetric macrocycles composed of alternately linked pyrene and binaphthyl moieties have been synthesized, among which a pyrenophane with ether linkers at the 2,7-positions of pyrenes demonstrated intense circularly polarized luminescence (CPL). The CPL exhibited by this pyrenophane is the highest among excimers and is insensitive to temperature, solvent, or concentration. The CPL originated from a twisting pyrene excimer with left-handed twist produced by (R)-binaphthyl moieties, showing a strong relationship between the electric and magnetic transition dipole moments.