Synthesis, Characterization, and Application of Europium(III) Complexes as Luminescent Markers of Banknotes

In this work, three complexes were synthesized from the trivalent europium ion (EuIII), using the picrate anion (pic), and delta-valerolactam (DVL), epsilon-caprolactam (EPK), and oenantholactam (OEN). The synthesized complexes [Eu(pic)3∙(DVL)3], [Eu(pic)3∙(EPK)3], and [Eu(pic)3∙(OEN)3] were studied as luminescent markers for application as security elements in Brazilian banknotes. All complexes showed red color emission with absorption at 397...