Synthesis of Chiral Binaphthyl-Viologen Derivatives and Circularly Polarized Luminescence Properties of Their Supramolecular Assemblies

Abstract

The binaphthyl molecule, with its axial chirality, serves as a crucial scaffold for chiral luminescent materials. However, circularly polarized luminescence (CPL) materials constructed by covalently integrating luminescent units with binaphthyl typically exhibit luminescence dissymmetry factors (glum) in the range of 10-5 to 10-3. Viologens (diquaternized bipyridinium salts), owing to their redox activity, strong electron-accepting characteristics, and structural programmability, provide a novel strategy for dynamically modulating chiroptical properties. In this study, we synthesized eight chiral binaphthyl-viologen derivatives through pyridyl group introduction into the chiral binaphthyl backbone followed by ionic complexation. Environmental regulation enabled the construction of supramolecular assemblies with exceptional CPL performance (glum values reaching 10-2 to 10-1) in solution aggregated states. Notably, R-BINMeV demonstrated a remarkable  glum  value of 0.3 with a quantum yield of 40.71%, forming large-scale well-organized helical nanorod superstructures. Molecular dynamics simulations confirmed that the assembly process primarily arises from strong electrostatic interactions within the compound system. This work establishes a new paradigm for designing high-performance CPL materials.

Keywords: Chiral Binaphthyl, Viologen, Circularly Polarized Luminescence, Supramolecular Assembly