Ultrasound-promoted chiral fluorescent organogel

Abstract

In this paper, we have described a chiral binaphthyl-based fluorescent organogel. Very interestingly, similar to sonocrystallisation of organics, ultrasound can promote the gelation while it cannot occur spontaneously at relatively high temperature or low concentration. The fluorescence enhancement of the gel obtained via ultrasound irradiation is observed. In solution there exist rapid dynamic equilibria between (S)-1 oligomers. The association interactions both between gelator molecules and between solvent and gelator molecules could together effect the helical growth of distorted (S)-1nanocrystals. The dihedral angle between the two naphthyl rings of the 1,1′-binaphthyl unit in (S)-1 will increase upon gelation. It has been assumed that ultrasound can play an important role in gelation with a high energy barrier. Sonication-induced gelation is a rapid crystallisation behavior yielding fiber-like aggregates in a metastable system.