Preparation and oxygen sensing properties of a sol–gel derived thin film based on a covalently grafted ruthenium(II) complex

The preparation and properties of luminescent oxygen sensing materials based on a sol–gel derived thin film containing covalently grafted Ru(bpy)32+ fragments are described in this article. The 2,2′-bipyridyl covalently grafted to 3-aminopropyltriethoxysilane through Si–CH2 covalent bonds was used as not only one of the sol–gel precursors but also the second ligand of Ru(bpy)2Cl2·2H2O complex to prepare the sol–gel derived silicates for oxygen sensors. The luminescence of covalently grafted Ru(II) within the thin film can be extremely quenched by oxygen with good sensitivity (I0/I100 = 4.3) and rapid response time (7 s), which suggests that the covalently grafting strategy presented in this article can be used for developing oxygen sensors. Furthermore, the thin film possesses the distinct advantages over those obtained by the physically entrapped method due to the Si–CH2 covalent bonds, including greatly minimized dye leaching effect, faster detection and simplified linear Stern–Volmer plot.