Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (5): 987-993.doi: 10.3866/PKU.WHXB201403112

• PHOTOCHEMISTRY AND RADIATION CHEMISTRY • Previous Articles     Next Articles

Photoisomerization Kinetics of IR125 and HDITCP in Ionic Liquids with Different Cation Alkyl Chain Lengths

YUAN Shu-Wei, LÜ Rong, YU An-Chi   

  1. Department of Chemistry, Renmin University of China, Beijing 100872, P. R. China
  • Received:2014-01-13 Revised:2014-03-11 Published:2014-04-25
  • Contact: YU An-Chi
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21273280).


The photoisomerization kinetics of IR125 and HDITCP in ionic liquids with different cation alkyl chain lengths were investigated by measuring their fluorescence lifetimes and quantum yields using steady-state absorption and fluorescence spectroscopies, and time-correlated single-photon counting experiments. It was found that the photoisomerization rate constants for IR125 and HDITCP in all the selected ionic liquids were almost identical and did not change with increasing ionic liquid viscosity. A comparison of the photoisomerization rate constants of IR125 and HDITCP in isoviscous aqueous glycerol solutions with those in ionic liquids showed that the photoisomerization energy barriers of IR125 and HDITCP in ionic liquids were about 2 kJ·mol-1 higher than those in the isoviscous aqueous glycerol solutions, indicating that specific interactions between IR125 or HDITCP and the ionic liquid restrain their respective photoisomerization processes in highly viscous ionic liquids.

Key words: Cyanine dye, Ionic liquid, Photoisomerization, Fluorescence quantum yield, Fluorescence lifetime