Generation of singlet oxygen in fullerene-containing media: 2. Fullerene-containing solutions

The generation of singlet oxygen in fullerene solutions is studied by luminescence methods upon excitation by pulsed, repetitively pulsed, and continuous radiation sources. The concentration of singlet oxygen in solutions is measured in stationary and pulsed irradiation regimes. The rate constants of quenching of O₂(¹Δ_g) by fullerenes C₇₀ and C₆₀ in the CCl₄ solution are measured to be (7.2 ± 0.1) × 10⁷ L mol^-1 s^-1 and less than 6 × 10⁴ L mol^-1 s^-1, respectively. The temperature and photolytic variations in the generation properties of the fullerene solution exposed to intense continuous radiation are studied by the methods of optical and EPR spectroscopy. Pulsed irradiation resulted in the production of singlet oxygen in suspensions of fullerene-like structures, in particular, astralenes. A liquid pulsed singlet-oxygen generator based on the fullerene solution in CCl₄ is developed and studied, in which the yield of O₂ (¹Δ_g) to the gas phase at concentrations up to 5 × 10¹⁶ cm^-3 is obtained.