Adducts of lanthanide β-diketonates with 2,4,6-tri(2-pyridyl)-1,3,5-triazine: Synthesis, structural characterization, and photoluminescence studies

Abstract

Adducts of lanthanide β-diketonates of the general formula LnL 3(TPTZ) were synthesized and structurally characterized by single crystal X-ray diffraction [Ln = Eu 3+, Tb 3+, Er 3+; L is the conjugate base of dibenzoylmethane (DBM), 1-benzoylacetone (BA), thenoyltrifluoroacetone (TTA), or 4,4,4-trifluoro-1-phenyl-1,3-butanedione (BTFA); TPTZ = 2,4,6-tri(2-pyridyl)-1,3,5-triazine, a rigid Lewis base with a large π system]. The lanthanide ion in each of these complexes is nonacoordinate with six β-diketonate oxygen atoms and three TPTZ nitrogen atoms, forming a coordination polyhedron best describable as a monocapped square antiprism. Characteristic red, green, and near infrared luminescence was observed for the Eu 3+, Tb 3+, and Er 3+ complexes, respectively. All complexes showed significantly enhanced luminescence quantum yields when compared with the corresponding aqua analogues, with one of the Eu 3+ complexes displaying a quantum yield of 69.7% in chloroform.