title: Exploring the conformational space of bridge-substituted dithienylcyclopentenes.
abstract: Stimuli responsive compounds and materials are of high interest in synthetic chemistry and materials science, with light being the most intriguing stimulus due to the possibility to remote control the physicochemical properties of a molecule or a material. There is a constant quest to design photoswitches with improved switching efficiency and especially diarylethene-type switches promise photo cyclization quantum yields up to unity. However, only limited attention has been paid towards the influence of the solution conformation on the switching efficiency. Here, we describe a detailed NMR spectroscopic investigation on the conformational distribution of bridge-substituted dithienylcyclopentenes in solution. We could discriminate between several photoactive and photoinactive as well as two diastereomorphous conformations and show that the trends observed in the switching efficiency match the conformer populations obtained from state of the art NMR parameters in solution.
authors: Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Strasse 4, 64287 Darmstadt (Germany).|Department of Chemistry, Sanofi Aventis Deutschland GmbH, Industriepark Höchst, 65926 Frankfurt am Main (Germany).
authors: Maic
authors: M
authors: Fredersdorf
authors: Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin (Germany).|Present address: Technische Universiteit Eindhoven, Molecular Science and Technology group Supramolecular Polymer Chemistry, P.O. Box 513, 5600 MB Eindhoven (The Netherlands).
authors: Robert
authors: R
authors: Göstl
authors: Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Strasse 4, 64287 Darmstadt (Germany).
authors: Andreas
authors: A
authors: Kolmer
authors: Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Strasse 4, 64287 Darmstadt (Germany).
authors: Volker
authors: V
authors: Schmidts
authors: Department of Chemistry, Sanofi Aventis Deutschland GmbH, Industriepark Höchst, 65926 Frankfurt am Main (Germany).
authors: Peter
authors: P
authors: Monecke
authors: Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin (Germany). sh@chemie.hu-berlin.de.
authors: Stefan
authors: S
authors: Hecht
authors: Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Strasse 4, 64287 Darmstadt (Germany). cthiele@thielelab.de.
authors: Christina M
authors: CM
authors: Thiele
keywords: NMR spectroscopy; NOE; conformational analysis; photochromism; residual dipolar couplings