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

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 x 10(-2) for SBNP-TPEHN, and -4.2 x 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.