Synthesis and luminescence properties of monophasic organic-inorganic hybrid materials incorporating europium(III)

Phosphine oxides 1-5 bearing one, two, or three hydrolyzable Si(OR)(3) groups have been prepared. They were treated with anhydrous europium salts [Eu(NO3)(3) or EuCl3] to afford complexes 6-10, the stoichiometry of which was found to be one Eu3+ for three P=O centers. The hydrolytic polycondensation of these complexes gave rise to nanostructured hybrid materials incorporating Eu3+. A solid-state P-31 NMR study of these hybrid materials has shown that Eu3+ remains well encapsulated within the materials when they are prepared from europium complexes with phosphine oxides bearing one hydrolyzable Si(OR)3 group. The luminescence behavior of these materials has been investigated. At room temperature, a very strong red emission was observed. The study of the emission lines at 2 K strongly suggested that there was predominantly one Eu3+ binding site within the materials.