CHEMICAL SYNTHESIS OF OZONE, ISOTOPIC LABELING, AND REDISTRIBUTION

Ozone is formed in good yield by reacting O2+ salts with water in HF at −78 °C. With isotopically labeled water 17O−16O−16O and 18O−16O−16O can be prepared, and other isotopomers could be made by starting with 17O2+ and 18O2+ precursors. 17O NMR spectroscopy and IR matrix spectroscopy are used for detection and decay of the isotopomers. The 17O or 18O label at the terminal position remains at −78 °C, but at higher temperatures scrambling of the atoms is observed. Under strict monomolecular conditions no scrambling is observed till 450 °C, however. Irradiation of ozone in a 15K argon matrix with λ = 254 nm affords scrambling of the label and formation of oxygen. Irradiation with λ > 420 nm initiates only scrambling with little decay. The possible mechanisms of the atomic scrambling are discussed.