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Studies of a photochromic model system using NMR with ex‐situ and in‐situ irradiation devices
Author(s) -
Wolff Christiane,
Kind Jonas,
Schenderlein Helge,
Bartling Hanna,
Feldmeier Christian,
Gschwind Ruth M.,
Biesalski Markus,
Thiele Christina M.
Publication year - 2016
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.4403
Subject(s) - photochromism , merocyanine , spiropyran , irradiation , in situ , chemistry , spectrometer , spectroscopy , photochemistry , proton nmr , analytical chemistry (journal) , optics , organic chemistry , physics , nuclear physics , quantum mechanics
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.