Influence of Different Carboxylic Acid Ligands on Luminescent Properties of Eu(Lc)₃phen (Lc = MAA, AA, BA, SA) Complexes

A series of rare earth europium complexes with different carboxylic acid ligands Eu(Lc)₃phen (Lc = MAA, AA, BA, SA) were synthesized. The complexes were characterized by FTIR, TG-DSC, XRD, UV absorption spectra, and photoluminescence spectra (PL) to study the structure, thermal stability, the energy absorption, and luminescent properties of the complexes. The results showed that the series complexes are all with good crystallization and relatively high thermal stability. The differences of the luminescent properties of complexes are caused by the different ligand structures. The absorption intensity of the carboxylic acid ligands, BA, was the strongest, followed by the MAA and AA and SA was the weakest. Therefore, the fluorescence intensity of the Eu(BA)₃phen was the strongest, followed by the Eu(MAA)₃phen and Eu(AA)₃phen and the Eu₂(SA)₃phen₂ was the weakest. All complexes showed good luminescence properties.