title: Studies of a photochromic model system using NMR with ex-situ and in-situ irradiation devices.
abstract: The switching behavior of a photochromic model system was investigated in detail via NMR spectroscopy in order to improve understanding of the compound itself and to provide ways to obtain insights into composition trends of a photo switchable (polymeric) material containing spiropyran/merocyanine units. In addition to the classical irradiation performed outside the magnet (ex-situ), a device for irradiation inside the NMR spectrometer (in-situ) was tested. Both setups are introduced, their advantages and disadvantages as well as their limits are described and the setup for future investigations of photochromic materials is suggested. The influence of different sample concentrations, irradiation procedures, and light intensities on the model system was examined as well as the dependence on solvent, temperature, and irradiation wavelengths. Using the recently published LED illumination device, it was even possible to record two-dimensional spectra on this model system with rather short half-life (7 min in DMSO). This way (13) C chemical shifts of the merocyanine form were obtained, which were unknown before. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Str. 16, D-64287, Darmstadt, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Wolff
authors.affiliation: Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Str. 16, D-64287, Darmstadt, Germany.
authors.forename: Jonas
authors.initials: J
authors.lastname: Kind
authors.affiliation: Ernst-Berl-Institut für Technische und Makromolekulare Chemie, Technische Universität Darmstadt, Alarich-Weiss-Str. 8, D-64287, Darmstadt, Germany.
authors.forename: Helge
authors.initials: H
authors.lastname: Schenderlein
authors.affiliation: Institut für Organische Chemie, Universität Regensburg, Universitätsstr. 31, D-93053, Regensburg, Germany.
authors.forename: Hanna
authors.initials: H
authors.lastname: Bartling
authors.affiliation: Institut für Organische Chemie, Universität Regensburg, Universitätsstr. 31, D-93053, Regensburg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Feldmeier
authors.affiliation: Institut für Organische Chemie, Universität Regensburg, Universitätsstr. 31, D-93053, Regensburg, Germany.
authors.forename: Ruth M
authors.initials: RM
authors.lastname: Gschwind
authors.affiliation: Ernst-Berl-Institut für Technische und Makromolekulare Chemie, Technische Universität Darmstadt, Alarich-Weiss-Str. 8, D-64287, Darmstadt, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Biesalski
authors.affiliation: Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Str. 16, D-64287, Darmstadt, Germany.
authors.forename: Christina M
authors.initials: CM
authors.lastname: Thiele
keywords: LED; NMR; UV/VIS; illumination device; merocyanine; photochromism; spiropyran