Chemical Synthesis of Ozone, Isotopic Labeling, and Redistribution

Ozone is formed in good yield by reacting O 2 + salts with water in HF at −78 °C. With isotopically labeled water 17 O− 16 O− 16 O and 18 O− 16 O− 16 O can be prepared, and other isotopomers could be made by starting with 17 O 2 + and 18 O 2 + precursors. 17 O NMR spectroscopy and IR matrix spectroscopy are used for detection and decay of the isotopomers. The 17 O or 18 O 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.