TY - JOUR
T1 - In Situ Observation of Photoswitching by NMR Spectroscopy
T2 - A Photochemical Analogue to the Exchange Spectroscopy Experiment
AU - Stadler, Eduard
AU - Tassoti, Sebastian
AU - Lentes, Pascal
AU - Herges, Rainer
AU - Glasnov, Toma
AU - Zangger, Klaus
AU - Gescheidt, Georg
PY - 2019/6/7
Y1 - 2019/6/7
N2 - We present 1D and 2D NMR experiments that provide in situ insights into photoinduced isomerizations. Irradiation during the mixing period of an exchange spectroscopy (EXSY) experiment leads to characteristic cross peaks in 2D spectra. The phototriggered exchange of magnetization occurring in photoswitchable (Z)- A nd (E)-isomers of three selected azo compounds provides information on the dynamic E/Z equilibria. We report the dependence of the diagonal-to-cross-peak ratio on concentration, light intensity, and mixing time. In analogy to exchange spectroscopy, this ratio mirrors the efficiency of light induced molecular transformations. Furthermore, we present a time-saving 1D version and a combined light/phase cycle scheme for enhanced detectability of photoinduced changes in the spectrum. This insight into light-induced structural changes is highly suited to study macromolecules, in which photoswitchable units trigger conformational changes.
AB - We present 1D and 2D NMR experiments that provide in situ insights into photoinduced isomerizations. Irradiation during the mixing period of an exchange spectroscopy (EXSY) experiment leads to characteristic cross peaks in 2D spectra. The phototriggered exchange of magnetization occurring in photoswitchable (Z)- A nd (E)-isomers of three selected azo compounds provides information on the dynamic E/Z equilibria. We report the dependence of the diagonal-to-cross-peak ratio on concentration, light intensity, and mixing time. In analogy to exchange spectroscopy, this ratio mirrors the efficiency of light induced molecular transformations. Furthermore, we present a time-saving 1D version and a combined light/phase cycle scheme for enhanced detectability of photoinduced changes in the spectrum. This insight into light-induced structural changes is highly suited to study macromolecules, in which photoswitchable units trigger conformational changes.
UR - http://www.scopus.com/inward/record.url?scp=85071728412&partnerID=8YFLogxK
U2 - 10.1021/acs.analchem.9b02613
DO - 10.1021/acs.analchem.9b02613
M3 - Article
C2 - 31380630
AN - SCOPUS:85071728412
SN - 0003-2700
VL - 91
SP - 11367
EP - 11373
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 17
ER -