Exchange interaction of O2 and nitroxide radical encounter pair as studied by time-resolved near IR luminescence spectroscopy of O2(1Δg)

Abstract

Phosphorescence spectral shift of singlet oxygen, O2(1Δg) was studied in the presence of a nitroxide radical quencher. The O2-nitroxide complex causes a blue-shifts in both molecular solvents and in ionic liquids. The amount of shift is found to be nearly the same for both solvents, about 50 cm−1. This shift was attributed to quartet-doublet energy separation of O2(3Σg−)-nitroxide pair by exchange interaction of O2 and nitroxide radical.