Energy Transfer Between Eu3+ and Nd3+ in Near-Infrared Emitting β-Triketonate Coordination Polymers

Isomorphousβ-triketonate-based lanthanoid polymers containing tris(4-methylbenzoyl)methanide (mtbm) and Rb⁺with formula,{[Ln(Rb)(mtbm)₄]₂}_n (Ln = Eu³⁺ and Nd³⁺) have been synthesised and structurally characterised. The photophysical properties for the Nd³⁺complex presented long lifetimes and relatively high quantum yields in comparison with analogous β-diketonate complexes. Mixed lanthanoid complexes were also formed and their luminescence properties studied, with effective sensitisation of the ⁴F_3/2 of Nd³⁺ via the ⁵D₀ of Eu³⁺, which is to the best of our knowledge the first example of Eu³⁺to Nd³⁺sensitisation in a coordination complex or polymer.