Judd-Ofelt characterization and energy transfer mechanism of highly luminescent europium(III) complexes with 1-(5-chloro-2-hydroxyphenyl)-1,3-butanedione

Abstract

Abstract Luminescent trivalent europium(III) complexes Eu(CHPB)3·(H2O)2 (C1), Eu(CHPB)3·neo (C2), Eu(CHPB)3·batho (C3), Eu(CHPB)3·phen (C4) and Eu(CHPB)3·bipy (C5) have been synthesized by involving a β-diketone ligand 1-(5-chloro-2-hydroxyphenyl)-1,3-butanedione (CHPB) and four ancillary ligands like neocuproine (neo), bathophenanthroline (batho), 1,10-phenanthroline (phen) and 2,2-bipyridyl (bipy). All the synthesized complexes C1–C5 were investigated by adopting various techniques such as elemental (CHN) analysis, 1H NMR spectroscopy, IR spectroscopy, UV–visible, thermal analysis (TG/DTG) and photoluminescence (PL) spectroscopy. The luminescence of complexes C1–C5 gets intensified suggesting a favorable position of triplet state of ligand and coligand from the emitting levels of metal ion. The luminescence quantum efficiencies and Judd-Ofelt intensity parameter Ω2 of the complexes also determined which advocate higher polarizable ligand field around central metal ion.