Novel Luminescent Soft Materials of Terpyridine-Containing Ionic Liquids and Europium(III)

Herein, we describe novel luminescent soft materials via reaction of Eu(3+)-coordinated carboxyl functionalized ionic liquids with terpyridine-functionalized imidazolium salts that are built from an imidazolium ring substituted on one side with a terpyridine derivative and, on the opposite side, a paraffin chain of various lengths. The obtained materials are either pastelike substances or viscous fluids, depending on the anions of the carboxyl functionalized ionic liquids. The soft luminescent materials were investigated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetry (TG), and luminescence spectroscopy. The soft materials show bright red emission irradiated with UV light, because of the energy transfer from terpyridine-functionalized imidazolium salts to the Eu(3+) ions. The absolute quantum yields of the materials were determined and the energy transfer efficiency was estimated according to the reported method.