Solvation and rotational relaxation of coumarin 153 in a new hydrophobic ionic liquid: An excitation wavelength dependence study

详细信息    查看全文

• 作者：Sudhir  ; Kumar Das ; Moloy  ; Sarkar  ; ;   ; ^{moloysarkar@gmail.com}
• 关键词：Ionic liquids ; Time dependent Stokes shift ; Solvation dynamics ; Excitation wavelength dependence ; Fluorescence anisotropy
• 刊名：Journal of Luminescence
• 出版年：2012
• 出版时间：February 2012
• 年：2012
• 卷：132
• 期：2
• 页码：368-374
• 全文大小：1070 K

文摘

The solvent relaxation and rotational dynamics of coumarin 153 have been investigated in a new room temperature ionic liquid, 1-(2-methoxyethyl)-1-methylpyrrolidiniumtris(pentafluorethyl)trifluorophosphate [[MOEMPL][FAP]], at three different excitation wavelengths with a variation in temperature. Wavelength -dependent fluorescence decay behavior of the probe molecule in the present medium has been investigated by studying the time dependent fluorescence Stokes shift in the ps¨Cns time scale. The dynamic fluorescence Stokes shift measurements suggest that the time-resolvable part of the solvation dynamics is biphasic in nature and the average solvation time depends on the excitation wavelengths. Rotational coupling constants, obtained from the time- resolved anisotropy data, indicate no specific interaction between the probe molecule and the ionic liquids. The excitation wavelength dependent solvation dynamics is attributed to the heterogeneous nature of the present ionic liquid.