Environment‐Sensitive Behavior of DCNP in Solvents with Different Viscosity,Polarity and Proticity
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| Authors: | Dr. Olaf Morawski Prof. Dr. Boleslaw Kozankiewicz Prof. Dr. Andrzej Miniewicz Prof. Dr. Andrzej L. Sobolewski |
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| Affiliation: | 1. Institute of Physics, Polish Academy of Sciences, Warsaw, Poland;2. Advanced Materials Engineering and Modelling Group, Faculty of Chemistry, Wroclaw University of Technology, Wroclaw, Poland |
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| Abstract: | A pyrazoline derivative, 3‐(1,1‐dicyanoethenyl)‐1‐phenyl‐4,5‐dihydro‐1H‐pyrazole (DCNP), is studied by using optical spectroscopy methods in several solvents at room and at low temperatures. The DCNP molecule reveals a complex photophysics behavior, which is sensitive to solvent polarity, proticity, temperature and viscosity and arises from the presence of two rotational degrees of freedom of the dicyanovinyl group—the torsion around the double C=C bond and the s‐trans–s‐cis isomerization around the single C?C bond—that differently behave in various environmental conditions. The fluorescence yield of a few percent and sub‐nanosecond decay times observed at room temperature make the compound useful for optical studies of liquid environments. The proticity of polar solvents can be detected with two‐exponential fluorescence decays. At low temperatures, DCNP can be used as solvent viscosity or temperature fluorescent sensor. |
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| Keywords: | charge transfer cis– trans isomerization hydrogen bonds molecular rotor torsion |
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