Synthesis and properties of photoisomerizable derivatives of isosorbide and their use in cholesteric filters

This paper describes the synthesis of photoisomerizable derivatives of isosorbide. These derivatives contain a stilbene or cinnamate moiety and can therefore be used as photoisomerizable chiral compounds in cholesteric liquid-crystalline mixtures. The reflection wavelength of cholesteric layers made from these mixtures is increased by UV irradiation due to the fact that the Z-isomers of these derivatives exhibit a lower helical twisting power than the corresponding E-isomers. The cinnamate derivatives are very suitable for use in cholesteric color filters that find application in liquid-crystal displays.