Table 1. Photophysical properties a of Ir-TEMPO1 and Ir-TEMPO2 in DMSO, DMF and methanol.
| Compounds (solvent) | τ 1 (μs) | A 1 (%) | τ 2 (μs) | A 2 (%) | χ 2 | φ em |
| Ir-TEMPO1 (DMSO) | 0.124 | 100 | — | — | 0.97 | 0.053 ± 0.0023 |
| Ir-TEMPO2 (DMSO) | 0.155 | 5.45 | 0.067 | 94.6 | 0.98 | 0.025 ± 0.0013 |
| Ir-TEMPO1 (DMF) | 0.096 | 100 | — | — | 1.02 | 0.037 ± 0.0010 |
| Ir-TEMPO2 (DMF) | 0.099 | 33.4 | 0.062 | 66.6 | 1.00 | 0.022 ± 0.0005 |
| Ir-TEMPO1 (MeOH) | 0.042 | 100 | — | — | 1.00 | 0.013 ± 0.0004 |
| Ir-TEMPO2 (MeOH) | 0.047 | 12.0 | 0.033 | 88.0 | 0.96 | 0.008 ± 0.0004 |
aLuminescence lifetimes (τi), their amplitudes (Ai) and the χ2 goodness of fit parameter, and the emission quantum yields (φem) ± standard deviation are shown. Excitation wavelengths were 480 nm (lifetime) and 470 nm (quantum yields); decays were recorded at the peak emission wavelength. Results from repeat decay measurements were in good agreement, and the uncertainties in reported values of lifetimes and amplitudes are ≤10%. Quantum yields are likely to be underestimated by ca. 10–20% (see ESI for details).