Oxygen-sensing properties of ormosil hybrid materials doped with ruthenium(II) complexes via a sol–gel process

Organically modified silicate (ormosil) materials doped with [4,4′-dimethyl-2,2′-bipyridine-bis(2,2′-bipyridine)] ruthenium(II) dichloride ([Ru-mbpy]2+) and [4,4′-dimethylformate-2,2′-bipyridine-bis(2,2′-bipyridine)] ruthenium(II) dichloride ([Ru-dmfbpy]2+) were prepared by a sol–gel procedure for oxygen-sensing applications. The results indicated that the concentrations of the Ru(II) diimine complexes obviously influenced the linearity of Stern–Volmer plots (I0 /I vs. O2%). The best suitable concentrations of [Ru-mbpy]2+ and [Ru-dmfbpy]2+ in the sol for oxygen sensors were found to be 1.0 × 10− 3 M and 2.5 × 10− 3 M, respectively. The fluorescence quenching time and recovery time of oxygen sensor doped with [Ru-mbpy]2+ (1.0 × 10− 3 M) were 18 s and 38 s and those doped with [Ru-dmfbpy]2+ (1.0 × 10− 3 M) were 13 s and 32 s, respectively. The oxygen sensor based on Ru(II) complex modified by esterification demonstrated excellent linear calibration relationship and improved long-term stability.