Preparation and luminescence of europium(iii) terpyridine complex-bridged polysilsesquioxanes

Abstract

Luminescent europium(III) terpyridine complex-bridged polysilsesquioxanes were prepared by hydrolysis and condensation of a precursor composed of a terpyridyl ligand bearing a urea group and a reactive siloxane part in the presence of europium(III) salts. Elementary analysis, FT-IR, SEM, luminescence spectra and luminescence decay analysis were employed to characterize the resulting materials. The effect of counteranions in the europium(III) salts on the morphology and luminescent properties of polysilsesquioxanes is investigated and discussed. It has been shown that porous europium(III) terpyridine complex-bridged polysilsesquioxanes can be obtained with Eu(ClO₄)₃·6H₂O whereas materials composed of irregular and aggregated nanoparticles are achieved when the perchlorate counteranions were replaced by chloride ones. The decay time of Eu³⁺ ions of the luminescent materials becomes longer as the molar ratio of the precursor to Eu³⁺ ions increases.