Coordination assembly and characterization of europium(iii) complexes covalently bonded to SBA-15 directly functionalized by modified polymer

Abstract

Novel organic/inorganic/polymeric mesoporous luminescent hybrid materials were prepared by covalently linking the binary and ternary Eu³⁺ complexes to the functionalized ordered mesoporous SBA-15 with the modified polymer poly(ethylene glycol) (PEG) as a “bi-functional bridge”. PEG was firstly modified with the coupling agent 3-(triethoxysilyl)propyl isocyanate (TEPIC) and covalently bonded to mesoporous silica SBA-15 through a co-condensation method (designated as PEG-SBA-15). Then, the new type of luminescent hybrid material (designated as Eu(PEG-SBA-15)₃) consisting of an inorganic Si–O network and an organic polymeric chain, was obtained by introducing the Eu(NO₃)₃ compound into the PEG-SBA-15 system via coordination reaction. With the addition of phen as the second ligand, the stronger luminescence intensity of the ternary Eu(PEG-SBA-15)₃phen hybrid was found. FT-IR, SAXRD, N₂ absorption measurements, TEM and photoluminescent spectra was used to characterize the hybrids. The results show that both the mesoporous hybrids exhibit the characteristic emission of Eu³⁺, high surface area, high ordered mesoporous structure and crystallinity, which suggests the polymer PEG can not only functionalize the mesoporous SBA-15 but also effectively sensitize the Eu³⁺. Moreover, the luminescence intensity, quantum efficiency and lifetime were enhanced by the introduction of ligand phen into the polymer functionalized mesoporous matrix.