The fabrication of helical fibers with circularly polarized luminescence via ionic linkage of binaphthol and tetraphenylethylene derivatives

Abstract

Assemblies with helical fiber nanostructures were fabricated via simple ionic linkage of a cationic tetraphenylethylene derivative (TPEHexN⁺) and an anionic binaphthyl derivative (SBNPSO₃⁻ or RBNPSO₃⁻). Chiroptical studies showed that the as-prepared SBNP–TPEHN and RBNP–TPEHN assemblies in the solid state exhibited high dissymmetry factors of +0.065 and −0.063 at the absorption band of TPE moieties, respectively. The circularly polarized luminescence of their films also had high average dissymmetry factors at 442 nm (+3.8 × 10⁻² for SBNP–TPEHN, and −4.2 × 10⁻² for RBNP–TPEHN). The fiber structures were characterized by scanning electron microscopy (SEM). A hypothetical mechanism for the formation of helical fibers is proposed.