Synthesis and photoluminescent property of Eu-containing organic–inorganic hybrid polyoxometalate

Sodium salt of photoluminescent Eu-containing polyoxometalate (Eu-POM) has been prepared and its chemical structure and physical properties characterized. The Eu-POM was unstable outside the pH range 5.5–8.5, and a pH just over 7 gave the best yield. We investigated the photoluminescent properties of Eu-POM with changing the reactants ratio of heteropolytungstate and EuCl3 · 6H2O. The Eu-POM was characterized by UV/Vis, FT-IR, 1H-NMR, PL and XPS. Eu-POM emits orange light of 590 nm when excited with the light of 280 nm and we made dodecyltrimethylammonium (DDTA) salt of Eu-POM (Eu-POM/DDTA) by exchange of the counter cation. The Eu-POM/DDTA is soluble in common organic solvents, while Eu-POM is only soluble in water and it emits reddish orange light of 625 nm when excited with light of 250 nm.