COMPLEXES OF Dy3+ , Er3+ , Yb3+ WITH CAFFEIC ACID AND 1,10-PHENANTROLINE: SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL ACTIVITY

Abstract

In this paper, a multi-analytical-technique approach was utilized to investigate the property of the
complexes of Dy3+, Er3+, Yb3+ with caffeic acid (HCaf) and 1,10-phenantroline (Phen). The synthesized
complexes were analyzed using FT-IR and thermal (TGA) analysis. IR spectroscopy results indicated the
successful synthesys of these complexes, with three of them consist of neutral monomeric molecules.
Thermal analysis demonstrated their considerable heat stability. The general molecular formula for the
synthesized complexes in solid state was Ln(Caf)3Phen (Ln: Dy, Er, Yb). These results were confirmed by
electrospray-ionization mass spectrometry (ESI-MS). Additionally, the antimicrobial properties of the
complexes and HCaf against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa were
studied by measuring the diameter of the inhibitory zone. The complexes present higher antibacterial
activity against bacterias compared to HCaf, likely due to the increased lipophilicity of these complexes.