Near-infrared-induced proton transfer studied by electron spin resonance

The effect of near-infrared (NIR) radiation (700-2000 nm) on water solution containing the nitroxide spin probe and selected amines has been studied. The concentration of free radical reversibly decreased upon irradiation. Ex planation of this phenomenon has been based on the known properties of nitr oxide radical in water. A reaction model for the process of reversible redu ction of the nitroxide in water in the presence of amine and oxygen has bee n elaborated. The key reaction proposed for this process is NIR-induced dec omposition of a complex between amine and nitroxide: R'NH3+ ... (ONR)-R-.. (C) 1999 Elsevier Science B.V. All rights reserved.