Near-infrared-induced proton transfer studied by electron spin resonance Original Research Article

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. Explanation of this phenomenon has been based on the known properties of nitroxide radical in water. A reaction model for the process of reversible reduction of the nitroxide in water in the presence of amine and oxygen has been elaborated. The key reaction proposed for this process is NIR-induced decomposition of a complex between amine and nitroxide: R′NH3+⋯ON⋅R.