Synthesis of diamondoid lanthanide-polyoxometalate solids as tunable photoluminescent materials

The reaction between polyoxometalate (POM) [TBA](12)[WZn{Zn(H2O)} (2)(ZnW9O34)(2)] (TBA = tetrabutyl ammonium) and lanthanide (Ln) nitrate (Ln = La, Eu and Tb) in a mixed solvent of CH3CN and DMF yielded three noncentrosymmetric diamondoid Ln-POM solid materials, {[Ln2(DMF) (8)(H2O)(6)][ZnW12O40]}.4DMF (Ln-POM; Ln = La, Eu and Tb). In these compounds, the {ZnW12O40} unit, transferred from the metastable [WZn{Zn(H2O)}(2)(ZnW9O34)(2)] cluster, acts as a tetradentate ligand to connect with four Ln nodes, while the Ln ion links up two {ZnW12O40} units. These compounds generated interesting luminescence emissions that are dependent on the Ln ions and their ratios. White light emission was obtained by a doped approach with a rational ratio of the Eu3+ and Tb3+ ions.