Asymmetric chiral disazo dopants with high anisotropy for versatile modulation of liquid crystal optics

As key elements, anisotropic chiral dopants determine the helical twisting power (HTP) of doped cholesteric liquid crystal (CLC) system by the host-guest interaction. To reveal the intrinsic structure-function relationship, we developed 3 novel asymmetric and photo-responsive chiral derivatives bearing axial chiral binaphthol moiety and disazo chromophore. They exhibited reversible photoisomerization, and rapidly induced helical degeneration of the doped CLC mixture under UV irradiation. Furthermore, highly asymmetric (R)-2'-hydroxy-[1,1'-binaphthalen]-2-yl 3,5-bis((E)-(4-butoxyphenyl)diazenyl)benzoate (molar absorption coefficient: 28,090 L.mol(-1).cm(-1); half-life period: 10.28 h; HTP: -34 um(-1) in E7) was adopted to construct the CLC film with excellent NIR-reflection adjusted by light, heat, and electric field. It is a promising photoswitch agent for application in advanced smart materials and optical devices. (C) 2021 Elsevier B.V. All rights reserved.