Abstract
The equilibrium and dynamic solvation responses of coumarin 153 (C153) in a range of deep eutectic solvents (DESs) based on choline chloride with either urea (molar ratio 1:2, ChCl:U), glycerol (1:2, ChCl:G), ethylene glycol (1:2, ChCl:E), or malonic acid (1:1, ChCl:Mal) were investigated using both steady-state and time-resolved fluorescence emission spectroscopy at room temperature (298 K). From steady-state fluorescence data, "red-edge effects" were observed in all the DESs studied, attributed to spatial heterogeneity of the DES matrix. Time-resolved Stokes shifts were used to quantify dynamic solvation with the solvation response function in DES found to be a biexponential function of time, which were used to obtain average solvation times (⟨τ s ⟩) which are generally faster in DES than in ionic liquids of comparable viscosity. Average solvation times showed a partial correlation with viscosity between different DESs. The choline chloride-glycerol DES showed deviation from the viscosity trend observed in the other DES for both dynamic and steady-state results. Rotational reorientation times obtained from dynamic anisotropy (r(t)) measured for these DESs showed a partial correlation with viscosity between different DESs. Determination of the DES rotational coupling with C153 showed more "slip"-like behavior than the previously reported ionic liquids and dipolar solvents.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
