Efficient, stable, tunable, and easy to synthesize, handle and recycle luminescent materials: [H2NMe2]3[Ln(iii)(2,6-dipicolinolate)3] (Ln = Eu, Tb, or its solid solutions)

Abstract

Three compounds with the general formulae [H₂N(Me)₂]₃[Ln(2,6-dpa)₃] were prepared from cheap and readily available reactants. Microcrystalline compounds could be isolated in high yields (>80%) by a simple filtration, after only one hour reaction time in refluxing DMF. The Eu and Tb compounds have been structurally characterized by single crystal X-ray diffraction. The compounds have unusual high-absorption coefficients (>95%) and quantum efficiencies (∼70%). Furthermore, they are thermally stable up to 250 °C and appear to be UV and water tolerant. The emission colour of the final compound can be easily fine-tuned, by varying the Eu : Tb ratio during the preparation.