PHOTOLUMINESCENCE OF A NEW WATER-INSOLUBLE POLYSILOXANE FILM CONTAINING PENDANT RU(BPY)(3)(2+) AND ITS QUENCHING BY DIOXYGEN

A new water-insoluble polysiloxane containing pendant Ru(bpy)(3)(2+) ( bpy = 2,2'-bipyridine) dine) was studied with respect to the photolumi nescence and its quenching by dioxygen. The emission was quenched by O -2 in water more efficiently than in gas phase, and the Stern-Volmer p lots showed a downward deviating curve. To determine which of several quenching models can be applied to the present system, the emission de cays under various O-2 concentration were measured, and analyzed by a double exponential decay. From the simulations of the decay using the kinetic parameters obtained from the model analysis, it has been concl uded that the quenching by O-2 is caused by static quenching (model 4) . The O-2 concentration in the film in contact with water estimated fr om the quenching parameters was much higher than the solubility of O-2 estimated from the solubility coefficient in a dry film. These result s suggest specific affinity of the polysiloxane for O-2 molecule in wa ter.