Two luminescent molecular hybrids composed of bridged Eu(III)-β-diketone chelates covalently trapped in silica and titanate gels

In the context, a kind of beta-diketone, dibenzoylmethane (DBM) was first grafted with the coupling reagent 3-(triethoxysilyl)-propyl isocyanate (TESPIC), and the as-derived monomers were introduced into inorganic network through powerful covalent bonds. Subsequently, two novel chemically bonded hybrid materials, Eu(III)-modified dibenzoylmethane with silica and titanate hosts, were prepared and characterized by IR, phosphorescence, fluorescence spectroscopy, time-resolved photoluminescence spectroscopy, and scanning electron microscopy (SEM). The above spectroscopic data indicate that the modified DBM could sensitize Eu(III) ions to exhibit attracting red luminescence in the two respective hosts. It is noted that the covalently bonded silicate hybrid material presents a stronger red/orange intensity ratio, longer lifetimes, and higher quantum efficiency than a covalently bonded titanate one and europium complex of DBM, suggesting that the silica network is more suitable for the emissions of covalently bonded composites than titanium oxide.