Table 1. Globally Fitted Lifetimes for 9-Methylpurine and Purine Obtained from a Target Analysis of the Transient Absorption Data Using a Sequential Kinetic Model.
| solvent | τ1 (ps) | τ2a (ps) | τ3 (ps) |
|---|---|---|---|
| 9-methylpurine | |||
| water (PBS, pH 7) | 0.25 ± 0.05 | 15 ± 5 | 600 ± 10 |
| acetonitrile | 0.15 ± 0.05 | 10 ± 1 | 350 ± 10 |
| chloroform | 0.15 ± 0.05 | 6 ± 1 | 380 ± 20 |
| cyclohexane | 0.30 ± 0.05 | 8 ± 2 | 195 ± 10 |
| purine free base | |||
| water (PBS, pH 7) | 0.20 ± 0.05 | 8 ± 3 | 645 ± 10 |
| acetonitrile | 0.19 ± 0.05 | 10 ± 3 | 360 ± 20 |
a
Average lifetime from a global fit analysis; its actual value increases in going from the UV to the visible probe wavelengths.