Singlet Molecular Oxygen from Superoxide Anion and Sensitized Fluorescence of Organic Molecules

The superoxide anion, O 2 -, evolves singlet molecular oxygen in dimethylsulfoxide solution. Pronounced water quenching of superoxide-sensitized luminescence is indicative of the preferential generation of the 1 σ g + state. Recent identification of O 2 - in the xanthine oxidase system suggests that the generation of singlet oxygen may also occur in enzymatic systems.