SiO2/polyester hybrid for immobilization of Ru(II) complex as optical gas-phase oxygen sensor

Organic-inorganic hybrid materials produced from tetraethoxysilane, citric acid and ethylene glycol in different mole ratios and consisting of Si-O-Si and Si-O-C nets are prepared and their molecular structure (IR and NMR spectroscopy), morphology (fluorescent microscopy, SEM and AFM), thermochemical behavior and fluorescence properties (excitation and emission spectra) are studied. The optically active, oxygen sensitive complex of tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) dichloride is immobilized in the so prepared matrix and the applicability of the composite as an optical oxygen sensor (response to O-2 in gaseous medium) is tested. The influence of the matrix composition on the linearity of the Stern-Volmer dependence and the films sensitivity to O-2 is studied.