Table 1.
Binding of dioxygen to hemoprotein models 1–4 (in dichloromethane): rates, redox potential, absorption spectrum, spin state, activation parameters
| Model | konO2, M−1·s−1 | E0 (mV) MeCN vs NHE | UV/Vis Deoxy, nm | Spin state* | Ref(s). |
|---|---|---|---|---|---|
| 1 | 5 × 107 | 180 | 428 | HS/LS | 15 |
| 2 (α3) | Too fast | 90 | 427–429 | HS/LS | This study |
| (α4) | 4.3 × 108 | — | 426 | HS | 15 |
| 3a (H) Wet | 1 | 87 | 426 | LS | This study |
| Dry | Too fast | — | 435 | HS/LS | |
| 3b (Pr) | 18 | — | 426 | LS | This study |
| 4a Cu(I) Wet | 6.0 | 123 | 426 | LS | This study |
| 4b Zn(II) | 6.5 | 96 | 426 | LS | This study |
| Hb, Mb | 107 to 108 | — | 435 | HS | 24–26 |
| CcO | 107 to 108 | — | 444 | HS | 20, 21, 31 |
Comparison with hemoproteins Hb, Mb (in buffer), and CcO.
*, as shown by Resonance Raman and 1H-NMR (Fig. 3 A–F).