Synthesis, properties, luminescence of mixed ligands complexes of acetylsalicylate and 1,10-phenantroline with some light rare earth elements

Abstract

Mixed ligands complexes of acetylsalicylic and 1,10-phenantroline of  Ln(III) with the general formula Ln(AcSa)₃(Phen).3H₂O (Ln: Nd, Sm, Eu; AcSa-: Acetylsalicylate, Phen: 1,10-phenantroline) have been prepared. The characterization  of  these complexes have been studied by IR, thermal analysis and mass-spectroscopy methods; The luminescence of complexes was investigated by measuring the excitation and emission spectra. IR spectra suggest that complexes have been synthesised successfully. Mass-spectroscopy showed that the complexes are monomes and they are stable. The intramolecular ligand-to-rare earth energy transfer mechanisms were discussed. The emission spectra of Eu(AcSa)₃(Phen).3H₂O consist of the ⁵D₀ → ⁷F₂  and ⁵D₀ → ⁷F₁  dominant transitions located at 614 nm and 593 nm, the weaker ⁵D₀ → ⁷F₄ transition located at 699 nm, the weakest  ⁵D₀ → ⁷F₃ transition located at 654 nm. The emission spectra of the Sm(AcSa)₃(Phen).3H₂O displayed three bands, in there, the ⁴G_5/2 – ⁶H_7/2 and ⁴G_5/2 – ⁶H_9/2 equivalent transitions located at 599 nm and 645 nm, the weakest  ⁴G_5/2 – ⁶H_5/2 transition located at 564 nm. The emission spectra of the Nd(AcSa)₃Phen.3H₂O  displayed one band at 440 nm, i.e. ⁴F_3/2 – ⁴I_9/2 energy level of Nd³⁺ was observed. These complexes showed room-temperature photoluminescence.