title: The solvation dynamics at millisecond scale of Pd(II)-meso-tetra(4-carboxyphenyl)porphine in solid imidazolium-sulfonate-based ionic liquids.
abstract: The phosphorescence behavior and solvation dynamics of Pd(II)-meso-tetra(4-carboxyphenyl)porphine (Pd-TCPP) in three imidazolium ionic liquids (ILs) has been studied. The phosphorescence excitation and emission position of Pd-TCPP are dependent on the polarity, constituent ions and structure of the ILs. The phosphorescence decay of Pd-TCPP in these ILs is bi-exponential, and the average lifetimes decrease in the following order: 0.844 ms in 1-butylimidazolium p-toluenesulfonate (HBIMTS)>0.472 ms in 1-butylimidazolium trifluoromethane sulfonate (HBIMTfO)>0.412 ms in 1-butyl-3-methylimidazolium p-toluenesulfonate (BMIMTS). The time-resolved phosphorescence emission spectra (TRPES) of Pd-TCPP display apparently blue-shifts with increasing time. The normalized Stokes shift correlation functions C(t) of Pd-TCPP in these ILs are mono-exponential, and the solvation relaxation times are 2.97, 47.7 and 12.1 ms in HBIMTfO, HBIMTS and BMIMTS, respectively. The solvation dynamics may be attributed to the collective motion of the ion pairs composed of imidazolium cations and counter anions to the area surrounding Pd-TCPP.
authors.affiliation: College of Chemistry, Beijing Normal University, Beijing 100875, People's Republic of China.
authors.forename: Yun Fang
authors.initials: YF
authors.lastname: Zhao
authors.forename: Li Li
authors.initials: LL
authors.lastname: Liu
authors.forename: Wei Jun
authors.initials: WJ
authors.lastname: Jin
mesh_terms: D007093:Imidazoles / Q000737:chemistry; D052578:Ionic Liquids / Q000737:chemistry*; D049449:Luminescence; D010165:Palladium / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013451:Sulfonic Acids / Q000737:chemistry
chemical_list: D007093:Imidazoles; D052578:Ionic Liquids; D011166:Porphyrins; D013451:Sulfonic Acids; C018395:tetracarboxyphenylporphine; D010165:Palladium