Photoswitchable molecular switches featuring both axial and tetrahedral chirality

Abstract

In this study, we develop a kind of novel photoswitchable chiral azo switches bearing both axially chiral binaphthyl center and single tetrahedrally chiral center with different configurations. The influence of the configuration of the tetrahedrally chiral centers and the introduction of a rigid structure on the helical twisting power (HTP) of the chiral azo switch was addressed in detail. Our results demonstrate that the import of the tetrahedrally chiral center dramatically decreased the HTP of the axially chiral azo switch, while the rigid long core increased the HTP. According to a molecular simulation based on Gaussian03 calculations at the B3LYP/6-31G(d) level, both the molecular configuration and the molecular aspect ratio were found to be the key factors influencing the HTP of the chiral azo switch. Finally, we utilize the above chiral azo switch to fabricate a photo-addressed, flexible liquid crystal device. This work provides an insight into the relationship between the chiral effect and molecular structure of chiral switches and their potential applications for photonic and display fields.