Table 4. ESP Charge Distributions Given for Atoms in the [4Fe–4S] Cluster, Its Coordinating Thiolates, and HMBPP from Two Representative Valence Isomers of the ROHPHE–(ROH) State When the [4Fe–4S] Cluster Is Oxidized50 and Reduced by One Electron.
| ROHPHE–(ROH) |
||||||
|---|---|---|---|---|---|---|
| αββα |
βααβ |
|||||
| ox | red | Δqa | ox | red | Δqa | |
| Fe1 | 0.527 | 0.549 | 0.022 | 0.515 | 0.516 | 0.001 |
| Fe2 | 0.472 | 0.528 | 0.056 | 0.472 | 0.559 | 0.087 |
| Fe3 | 0.548 | 0.617 | 0.069 | 0.575 | 0.698 | 0.123 |
| Fe4 | 0.440 | 0.502 | 0.062 | 0.444 | 0.490 | 0.046 |
| sum | 1.987 | 2.196 | 0.209 | 2.007 | 2.263 | 0.257 |
| S1 | –0.491 | –0.636 | –0.145 | –0.495 | –0.678 | –0.183 |
| S2 | –0.293 | –0.362 | –0.069 | –0.278 | –0.340 | –0.062 |
| S3 | –0.348 | –0.505 | –0.156 | –0.357 | –0.514 | –0.157 |
| S4 | –0.591 | –0.798 | –0.206 | –0.605 | –0.825 | –0.220 |
| sum | –1.724 | –2.301 | –0.577 | –1.735 | –2.357 | –0.622 |
| C12 | –0.266 | –0.413 | –0.148 | –0.261 | –0.387 | –0.125 |
| C96 | –0.332 | –0.478 | –0.146 | –0.334 | –0.499 | –0.165 |
| C197 | –0.380 | –0.539 | –0.159 | –0.404 | –0.567 | –0.162 |
| sum | –0.977 | –1.430 | –0.452 | –1.000 | –1.453 | –0.453 |
| total cluster | –0.714 | –1.534 | –0.820 | –0.728 | –1.546 | –0.817 |
| OC4 | –0.386 | –0.412 | –0.026 | –0.388 | –0.418 | –0.030 |
| C3 | 0.013 | 0.024 | 0.010 | 0.019 | 0.028 | 0.009 |
| C2 | –0.213 | –0.237 | –0.024 | –0.241 | –0.269 | –0.029 |
| total HMBPP | –0.296 | –0.370 | –0.075 | –0.317 | –0.418 | –0.101 |
| cluster + HMBPP | –1.010 | –1.905 | –0.895 | –1.046 | –1.964 | –0.918 |
a
The difference in charge (Δq) between the oxidized and 1e– reduced atoms is indicated.