Synthesis of Tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) Complexes Possessing a Linker Arm for Use in Sol-gel-based Optical Oxygen Sensor

Abstract

Although these developments generally employ theimpregnation or doping of dye molecules into sol-gels, suchmethods could cause leaching of dye molecules from thehost sol-gel matrix to the analyte solution during liquid-phase sensing and could eventually reduce sensor lifetime.To circumvent the problem of leaching, an alternative methodis the covalent immobilization of dye molecules on the sol-gel matrix. Therefore, to develop a stable, oxygen-sensingmaterial without the leaching problem, we investigated theformation of covalent bonds between fluorophores and sol-gel precursors. Herein, we report the synthesis of Ru(II)complexes possessing a linker arm which is a functionalgroup for forming a covalent linkage with an appropriatesilicate precursor.Tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) com-plex is the fluorophore of choice in this work since it is awell-known fluorescent dye quenched dynamically by oxygen.