Enhanced chemical reactivity of the tris-(2,2′-bipyridyl)ruthenium(II) complex due to electrostatic binding to colloidal particles as evidenced on the basis of the reaction with azidyl radicals
Abstract
Ion binding of Ru(bpy)32+ ions to negatively charged colloidal particles (silica or titania) or poly(vinyl sulfate) ions causes a pronounced reactivity increase. Respective evidence comes from the fact that the otherwise unreactive Ru(II) ions react with azidyl radicals (N3•) provided they are firmly attached to the negatively charged particles. The increase in reactivity is explained in terms of strong electronic coupling between the Ru(II) complex and the host particle. As a consequence the oxidation potential of the system Ru(bpy)33+/Ru(bpy)32+ is significantly reduced.