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.