[Ru(bpy)3]2+ structure, emission and reactivity. A) Structure and B) absorbance and emission spectrum of the ICI probe [Ru(bpy)3]2+. C) Reactivity of [Ru(bpy)3]2+. The probe, which is originally RuII, can be oxidized with (NH3)2Ce(NO3)6 to RuIII, which is reduced to RuII*, an excited-state metal complex that emits a photon upon decay trough a normal fluorescence mechanism.