Preparation and photoluminescence of some europium (III) ternary complexes with β-diketone and nitrogen heterocyclic ligands

Abstract

Preparation and photoluminescence behavior of four new europium (III) ternary complexes with β-diketones (1-(6-methoxy-naphthalen-2-yl)-3-phenyl-propane-1,3-dione (MNPPD) and 1-(4-tert-butyl-phenyl)-3-(6-methoxy-naphthalen-2-yl)-propane-1,3-dione (BPMPD)) and 2,2-dipyridine (Bipy) or 1,10-phenanthroline (Phen) were reported, in the solid state. Complexes Eu(MPPD)3·Bipy, Eu(BMPD)3·Bipy, Eu(MPPD)3·Phen and Eu(BMPD)3·Phen were characterized by elemental analysis, FT-IR, 1H NMR, UV–vis absorption. The emission spectra show narrow emission bands that arise from the 5D0→7FJ (J=0–4) transitions of the europium ion. Based on the emission spectra and luminescence decay curves in solid state, the intensity parameters (Ωt), lifetime (τ) and emission quantum efficiency (η) were determined. The Ω2 values indicate that the Eu(III) ion in these complexes is in a highly polarizable chemical environment. Complexes Eu(MPPD)3·Bipy and Eu(MPPD)3·Phen showed a longer lifetime (τ) and a higher luminescence quantum efficiency (η), which indicated that the energy transfer to the europium ion from MNPPD ligand is more efficient than that from BPMPD ligand.