1h-phenalen-1-one-2-sulfonic Acid - an Extremely Efficient Singlet Molecular-oxygen Sensitizer for Aqueous-media

We report on the synthesis of H-1-phenalen-1-one-2-sulfonic acid (PNS) and its ability to generate singlet molecular oxygen in aqueous media. Treatment of H-1-phenalen-1-one with sulfuric acid yields PNS as the solely reaction product. This compound sensitizes the formation of singlet oxygen in D2O with a quantum yield of 1.03 +/- 0.10. Its non-fluorescing character makes it an attractive candidate for singlet oxygen studies in aqueous media.