TY - JOUR
AU - Métivier, Rémi
AB - Although 4‐dicyanomethylene‐2‐methyl‐6‐(p‐dimethylamino‐styryl)‐4H‐pyran (DCM) has been known for many decades as a bright and photostable fluorophore, used for a wide variety of applications in chemistry, biology and physics, only little attention has been paid so far to the presence of multiple isomers and conformers, namely s‐trans‐(E), s‐cis‐(E), s‐trans‐(Z), and s‐cis‐(Z). In particular, light‐induced E–Z isomerization plays a great role on the overall photophysical properties of DCM. Herein, we give a full description of a photoswitchable DCM derivative by a combination of structural, theoretical and spectroscopic methods. The main s‐trans‐(E) isomer is responsible for most of the fluorescence features, whereas the s‐cis‐(E) conformer only contributes marginally. The non‐emitting Z isomers are generated in large conversion yields upon illumination with visible light (e.g., 485 or 514 nm) and converted back to the E forms by UV irradiation (e.g., 365 nm). Such photoswitching is efficient and reversible, with high fatigue resistance. The E→Z and Z→E photoisomerization quantum yields were determined in different solvents and at different irradiation wavelengths. Interestingly, the fluorescence and photoisomerization properties are strongly influenced by the solvent polarity: the fluorescence is predominant at higher polarity, whereas photoisomerization becomes more efficient at lower polarity. Intermediate medium (THF) represents an optimized situation with a good balance between these two features.
TI - Photophysical Properties of 4‐Dicyanomethylene‐2‐methyl‐6‐(p‐dimethylamino‐styryl)‐4H‐pyran Revisited: Fluorescence versus Photoisomerization
JF - Chemistry - A European Journal
DO - 10.1002/chem.202002828
DA - 2020-11-11
UR - https://www.deepdyve.com/lp/wiley/photophysical-properties-of-4-dicyanomethylene-2-methyl-6-p-aEYHDF4v1P
SP - 14341
EP - 14350
VL - 26
IS - 63
DP - DeepDyve
ER -