Photoinduced electron and energy transfer from coumarin 153 to perylenetetracarboxylic diimide in bmimPF6/TX-100/water microemulsions

A perylenetetracarboxylic diimide (PDI) compound with an attached hydrophilic polyoxyethylene group at the imide nitrogen position was designed and synthesized. Photoinduced electron and energy transfer between coumarin 153 (C-153) and PDI in a ternary microemulsion with an ionic liquid (bmimPF6/TX-100/H2O) were investigated by steady state electronic absorption and fluorescence spectroscopy. The results revealed that both PDI and C-153 resided at the interface between the surfactant TX-100 and the ionic liquid bmimPF6 in the ternary microemulsions. The absorption spectra suggested no interactions between C-153 and PDI in the ground states, but the fluorescence spectra revealed the presence of an efficient electron transfer and a less efficient energy transfer from C-153 to PDI. Moreover, the electron transfer was much more efficient in microemulsions than that in homogeneous conventional organic solvents due to the unique micro-environment of the microemulsion.

Both C-153 and PDI stay at the interface between IL and TX-100 in confined microemulsions. The fluorescence quenching of C-153 by PDI is much more efficient in microemulsions than that in homogeneous conventional organic solvents by accelerating the electron transfer process.Figure optionsDownload high-quality image (94 K)Download as PowerPoint slideResearch highlights
► A perylenetetracarboxylic diimide (PDI) which can dissolve in ionic liquids (ILs) has been prepared.
► PDI adsorbs at the interface between IL and the surfactant TX-100 in the microemulsions.
► The additive coumarin C-153 transfers energy and electrons efficiently to PDI under photo-excitation.
► The microemulsion environment favors the electron transfer process.