Synthesis and Properties of Highly Efficient Luminescent Zn‐Tb and Zn‐Eu Multimetal Complexes

Abstract

ABSTRACT Salen‐type Schiff‐base ligands (H 2 L) were synthesized through the condensation reaction between 1,2‐diphenylethane‐1,2‐diamine and o‐vanillin. Three novel luminescent Zn‐Ln complexes, [ZnL] 2 Ln (Ln = Gd, Tb, Eu), were successfully prepared by reacting the zinc complex (ZnL) with LnCl 3 . Subsequent treatment of [ZnL] 2 Ln with dibenzoylmethane yielded three dinuclear derivatives, β‐[ZnL]Ln (Ln = Gd, Tb, Eu). All complexes were comprehensively characterized by single‐crystal X‐ray diffraction and FT‐IR spectroscopy. Structural analyses revealed that complexes 1–3 adopt trinuclear Zn‐Ln‐Zn architectures, whereas complexes 4–6 exhibit dinuclear Zn‐Ln configurations. Solid‐state photoluminescence measurements demonstrated quantum yields of 27.94% (ZnL), 0.90% ([ZnL] 2 Eu), 1.82% ([ZnL] 2 Tb), 1.05% ([ZnL] 2 Gd), 0.65% (β‐[ZnL]Eu), 1.16% (β‐[ZnL]Tb), and 0.70% (β‐[ZnL]Gd), indicating their potential as advanced fluorescent rare‐earth materials. The LED devices based on complexes β‐[ZnL]Eu and β‐[ZnL]Tb exhibit stronger emission intensities compared to those based on complexes [ZnL] 2 Eu and [ZnL] 2 Tb. The obtained complexes were fabricated in LED; the CIE chromaticity coordinates of complexes β‐[ZnL]Eu and β‐[ZnL]Tb are (0.344, 0.316) and (0.347, 0.323), respectively, which are very close to the standard white light coordinates (0.33, 0.33).