Aggregation-induced emission of a Eu(III) complex via ligand-to-metal charge transfer

Abstract Aggregation-induced emission (AIE) of a Eu(III) complex using ligand-to-metal charge transfer band is demonstrated. The Eu(III) complex comprises three anionic 2,2,6,6-tetramethyl-3,5-heptanedionate (tmh) ligands and one large π-conjugated neutral dipyrido[3,2-f:2′,3′-h]quinoxaline (dpq) ligand. Crystalline H-aggregates of the Eu(III) complex were characterized by X-ray crystal structure analysis. H-aggregation-induced emission (H-AIE) properties were evaluated using emission spectra, emission lifetime, and quantum yields. The energy transfer efficiency of the H-aggregate in the solid state is five times larger than that of the isolated Eu(III) complex in solution.