title: Fast and Efficient Oxidative Cycloreversion Reaction of a π-Extended Photochromic Terarylene.
abstract: We report herein a dramatic improvement in the kinetics and efficiency of an oxidative cycloreversion reaction of photochromic dithiazolylthiazoles. The cycloreversion reaction of a colored isomer of dithiazolylthiazole proceeds not only by photo-irradiation, but also through chemical oxidation with a net efficiency far exceeding 100 % owing to a chain reaction mechanism. By introducing aromatic groups on the reactive carbon atoms at the ends of a photoreactive 6π system in a dithiazolylthiazole, the net bleaching reaction rates were increased by up to 1300-fold, and turnover rates increased by two orders of magnitude. Based on a combination of classical kinetic analyses and DFT calculations, we attribute this improvement to acceleration of the rate-determining step to produce the active species in the chain-reaction oxidative cycloreversion.
authors.affiliation: Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara, Japan.|NAIST-CEMES International Collaborative Laboratory, CEMES-CNRS (UPR 8011), 29 rue Jeanne Marvig, BP94347, 31055, Toulouse, France.
authors.forename: Jan Patrick
authors.initials: JP
authors.lastname: Calupitan
authors.affiliation: Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Nakashima
authors.affiliation: Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Hashimoto
authors.affiliation: Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara, Japan. tkawai@ms.naist.jp.|NAIST-CEMES International Collaborative Laboratory, CEMES-CNRS (UPR 8011), 29 rue Jeanne Marvig, BP94347, 31055, Toulouse, France. tkawai@ms.naist.jp.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Kawai
keywords: chain reaction; density functional calculations; kinetics; photochromism; terarylene