Efficient red emission from PMMA films doped with 5,6-DTFI europium(iii) complexes: synthesis, structure and photophysical properties

Abstract

A new β-diketone, 5,6-dimethoxy-2(2,2,2-trifluoroethyl)-1-indone (5,6-DTFI), has been designed and synthesized. Two series of four 5,6-DTFI Sm³⁺ and Eu³⁺ complexes, namely, Eu(5,6-DTFI)₃(H₂O)₂ (1), Eu(5,6-DTFI)₃(Phen) (2), Sm(5,6-DTFI)₃(H₂O)₂ (3) and Sm(5,6-DTFI)₃(Phen) (4) (Phen = 1,10-phenanthroline), have been isolated. X-ray diffraction analysis reveals that all complexes 1–4 are of mononuclear structures. Luminescent and phosphorescent spectra of complexes 1–4 show strong characteristic emissions of the corresponding Eu³⁺ and Sm³⁺ ions. Upon complexes 1 and 2 were doped into the poly(methylmethacrylate) (PMMA) forming the films, the PMMA polymer matrix acting as a co-sensitizer for Eu³⁺ ion enhances the luminescent lifetimes, overall quantum yields and the thermal stability in comparison with the precursor complexes.