title: Photostability of 4,4'-dihydroxythioindigo, a mimetic of indigo.
abstract: The photochemical properties of indigo, a widely used industrial dye, has attracted both experimentalists and theoreticians from the beginning. Especially the high photostability of indigo has been the subject of intensive research. Recently, it was proposed that after photoexcitation an intramolecular proton transfer followed by a nonradiative relaxation to the ground state promote photostability. In indigo the hydrogen bond and the proton transfer occur between the opposing hemiindigo parts. Here, we provide experimental and theoretical evidence that a hydrogen transfer within one hemiindigo or hemithioindigo part is sufficient to attain photostability. This concept can serve as an interesting strategy towards new photostable dyes for the visible part of the spectrum.
authors.affiliation: Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund (Germany).
authors.forename: Marc
authors.initials: M
authors.lastname: Dittmann
authors.forename: Franziska F
authors.initials: FF
authors.lastname: Graupner
authors.forename: Benjamin
authors.initials: B
authors.lastname: Maerz
authors.forename: Sven
authors.initials: S
authors.lastname: Oesterling
authors.forename: Regina
authors.initials: R
authors.lastname: de Vivie-Riedle
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Zinth
authors.forename: Martin
authors.initials: M
authors.lastname: Engelhard
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Lüttke
mesh_terms: D004355:Drug Stability; D007203:Indigo Carmine / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000528:radiation effects; D007536:Isomerism; D008956:Models, Chemical; D008958:Models, Molecular; D010777:Photochemistry; D011522:Protons; D014466:Ultraviolet Rays
chemical_list: C000592513:4,4'-dihydroxythioindigo; D011522:Protons; D007203:Indigo Carmine
keywords: dyes/pigments; photochemistry; proton transfer; thioindigo; ultrafast spectroscopy