Synthesis, structures and photoluminescence of uranyl polyoxometalate clusters based on trilacunary [TeW9O33]8-

Synthesis of uranyl polyoxometalate clusters attract more attention but remain great challenging. Herein, two uranyl polyoxometalate inorganic clusters of {Na-6(NH4)(19)[(TeW9O33)(4)[TeO2(OH)](UO2)(4)(H2O)(2)]center dot 50H(2)O}(n) (1, Te-U-4) and (NH4)(18){Na@[(TeW9O32OH)(TeW9O33)(2)[TeO(OH)][W3O12(mu(3)-OH)](UO2)(6)(mu(2)-OH)(2)H2O]}center dot 75H(2)O (2, Te-U-6) were prepared using trilacunary [alpha-B-TeW9O33](8-) as inorganic ligands. Structural analysis showed that compound 1 is a one-dimensional chain structure formed by tetrameric aggregates of [(alpha-B-TeW9O33)(4)(TeO2(OH))(UO2)(4)(H2O)(2)](25-) as nodes and Na+ ions as linkers. The anionic tetrameric aggregates in 1 is made of two sandwich-type dimers of [(TeW9O33)(2)(UO2)(2)H2O](12-) bridged by a [TeO2(OH)](-) unit. Compound 2 is a triangular trimeric architecture templated by Na+ ion. The solid-state luminescence emission spectra of compounds 1 and 2 show the characteristic peaks of uranyl ions. Compound 1 with one-dimensional chain structure exhibited a higher photoluminescence quantum yields (PLQY) than that of 2, due to the more rigidity of 1 reducing the nonradiative transitions.

Automated summary

This study successfully synthesized two uranyl polyoxometalate clusters with one-dimensional chain structure and trimeric architecture, respectively. It was found that the uranyl polyoxometalate cluster with one-dimensional chain structure exhibited a higher photoluminescence quantum yield compared to the one with trimeric architecture.