Sonochemiluminescence of Ru(bpy) in aqueous solutions. Evidence of the formation of hydrated electrons during the single-bubble sonolysis in a neutral aqueous medium.

Consideration is given to single and multibubble sonochemiluminescence (SCL) in acidic Ru(bpy) aqueous solutions due to the light emission of the excited ion *Ru(bpy) at 613 nm. Spectrophotometrically controlled reduction of Ru(bpy) to Ru(bpy) occurs in both regimes of sonolysis. The kinetics parameters of reduction under SCL during the multibubble sonolysis do not depend on the H concentration in the solution (0.

Activation of Ru(bpy) multibubble sonochemiluminescence in alkaline aqueous solutions by a hydrated electron.

The sonochemiluminescence in 10 M aqueous solutions of Ru(bpy)Cl was studied in the presence of NaOH and KOH (up to 0.4 M). The observed increase in the steady-state emission intensity from Ru(bpy) as compared with the intensity in neutral solutions was attributed to conversion of H resulting from water sonolysis to e.

Mechanism of multibubble sonochemiluminescence of Ru(bpy) in neutral aqueous solutions.

The effect of hydrated electron scavengers, Cd, NO, (CH)CO, and OH radical scavengers, Cl, I, on the intensity of Ru(bpy) ion sonochemiluminescence observed in neutral aqueous solutions of Ru(bpy)Cl was studied. The variation trends in the luminescence intensity due to the action of the scavengers indicated three main reactions sufficient to explain the sonochemiluminescence in a neutral medium. These reactions are the Ru(bpy) reduction and oxidation with the H atom and the OH radical, respectively, and disproportionation of the Ru(bpy) and Ru(bpy) ions thus formed, giving rise to the multibubble sonochemiluminescence emitter, namely, the electronically excited Ru(bpy) ion.

Sonochemiluminescence in an aqueous solution of Ru(bpy)Cl.

The sonochemiluminescence spectra of electron-excited ions [Ru(bpy)] was registered for the first time during sonolysis of argon saturated aqueous solutions of Ru(bpy)Cl with low concentration. At single-bubble sonolysis, the luminescence band of ruthenium is recorded at a concentration of Ru(bpy)Cl from 10 M, and at multibubble from 10 M. Possible mechanisms for the appearance of the band of a tris-bipyridyl ruthenium(II) complex on the background of an structureless continuum of water in the spectra of sonoluminescence are analyzed.