title: Dynamic photoswitching of helical inversion in liquid crystals containing photoresponsive axially chiral dopants.
abstract: Chirality switching is intriguing for the dynamic control of the electronic and optical properties in nanoscale materials. The ability to photochemically switch the chirality in liquid crystals (LCs) is especially attractive given their potential applications in electro-optic displays, optical data storage, and the asymmetric synthesis of organic molecules and polymers. Here, we present a dynamic photoswitching of the helical inversion in chiral nematic LCs (N*-LCs) that contain photoresponsive axially chiral dopants. Novel photoresponsive chiral dithienylethene derivatives bearing two axially chiral binaphthyl moieties are synthesized. The dihedral angle of the binaphthyl rings changes via the photoisomerization between the open and closed forms of the dithienylethene moiety. The N*-LCs induced by the dithienylethene derivatives that are used as chiral dopants exhibit reversible photoswitching behaviors, including a helical inversion in the N*-LC and a phase transition between the N*-LC and the nematic LC. The present compounds are the first chiral dopants that induce a helical inversion in N*-LC via the photoisomerization between open and closed forms of the dithienylethene moiety.
authors.affiliation: Department of Polymer Chemistry, Kyoto University, Katsura, Kyoto 615-8510, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hayasaka
authors.forename: Tatsuaki
authors.initials: T
authors.lastname: Miyashita
authors.forename: Masaru
authors.initials: M
authors.lastname: Nakayama
authors.forename: Kenji
authors.initials: K
authors.lastname: Kuwada
authors.forename: Kazuo
authors.initials: K
authors.lastname: Akagi
mesh_terms: D050866:Liquid Crystals / Q000737:chemistry*; D015394:Molecular Structure; D009281:Naphthalenes / Q000138:chemical synthesis / Q000737:chemistry*; D055668:Photochemical Processes; D013237:Stereoisomerism; D013816:Thermodynamics; D013876:Thiophenes / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D009281:Naphthalenes; D013876:Thiophenes; C412331:2,2'-binaphthyl