Intriguing light-emission features of ketoprofen-based Eu(III) adduct due to a strong electron–phonon coupling

Abstract

Lanthanide-based coordination compounds of molecular formula [Ln(keto) 3 (H 2 O)], where Ln¼ Gd, Eu and keto¼ ketoprofen, were synthesized and their photoluminescence features were detailed in the 12-300 K interval. The emission spectra of [Eu(keto) 3 (H 2 O)] reveal a strong dependence with the temperature, well-illustrated by an unusual large blue-shift (∼17 cm À 1) of the 5 D 0-7 F 0 transition as the temperature is raised. The arithmetic difference between the absorption spectrum of [Eu(keto) 3 (H 2 O)] with that of [Gd(keto) 3 (H 2 O)] pointed out the presence of a ligand-to-metal charge transfer (LMCT) band (320-370 nm). From the [Gd(keto) 3 (H 2 O)] phosphorescence the energy of the keto-related triplet states was determined showing a large overlap with the intra-4f 6 levels and a strong electron-phonon coupling. The high-resonance between the LMCT and triplet states and the Eu 3 þ levels leads to a strong dependence of the 5 D 0 lifetime value, typical of the presence of operative energy transfer processes.

Lanthanide(III) complexes with tridentate Schiff base ligand, antioxidant activity and X-ray crystal structures of the Nd(III) and Sm(III) complexes

“…[1][2][3] The intriguing structures [4][5][6] and the potential uses in a wide variety of areas as diagnostic tools in biology 7 catalysis, 8 luminescence 9 and magnetism 10 reinforce the interest of chemists in these areas of research. A few years ago our research group initiated a project concerning rare earth metal chemistry 11 in a search for unusual molecular materials.…”

Thermal behavior, spectroscopic studies and free radical scavenging potential of some mefenamate trivalent lanthanides (Sm, Eu, Gd, Tb and Dy)

“…Examples include the finding that ketoprofen [6,7] and naproxen [8] compounds exhibit more anti-inflammatory activity than free ligands. Europium complexe of ketoprofen have an intriguing luminescent property and can be used as a nanothermometer due to its strong temperature dependence [9]. Terbium compounds produced by carproxen have also exhibited strong energy transfer between the ligand and the metal, which leads to a substantial luminescent property [10].…”

Synthesis, thermal behavior, and spectroscopic study of the solid nalidixate of selected light trivalent lanthanides

“…Consequently, the remaining water molecules in our compounds are located in the outer coordination sphere, and the lanthanide (III) ion has a coordination number of 7. This coordination number also occurs in other lanthanide carboxylate complexes based in pharmaceutical compounds such as ketoprofen [35] and naproxen [36].…”