Table 13. ESP Charge Distributions Given for Atoms in the [4Fe–4S] Cluster, Its Coordinating Thiolates, and HMBPP from Two Representative Valence Isomers of the ROHP–EH(η2-ring) State When the [4Fe–4S] Cluster Is Oxidized and Reduced by One Electron.
| ROHP–EH |
||||||
|---|---|---|---|---|---|---|
| αββα |
βααβ |
|||||
| ox (η2-ring) | red (η2-ring) | Δqa | ox (η2-ring) | red (η2-ring) | Δqa | |
| FE1 | 0.386 | 0.373 | –0.012 | 0.387 | 0.307 | –0.080 |
| FE2 | 0.464 | 0.533 | 0.068 | 0.459 | 0.512 | 0.053 |
| FE3 | 0.621 | 0.645 | 0.023 | 0.618 | 0.692 | 0.074 |
| FE4 | 0.459 | 0.515 | 0.056 | 0.455 | 0.494 | 0.040 |
| sum | 1.930 | 2.065 | 0.135 | 1.919 | 2.005 | 0.087 |
| S1 | –0.458 | –0.583 | –0.125 | –0.458 | –0.592 | –0.133 |
| S2 | –0.268 | –0.328 | –0.060 | –0.268 | –0.267 | 0.001 |
| S3 | –0.448 | –0.597 | –0.149 | –0.446 | –0.570 | –0.124 |
| S4 | –0.566 | –0.740 | –0.173 | –0.563 | –0.691 | –0.129 |
| sum | –1.741 | –2.248 | –0.508 | –1.735 | –2.119 | –0.385 |
| C12 | –0.243 | –0.396 | –0.153 | –0.238 | –0.346 | –0.108 |
| C96 | –0.305 | –0.434 | –0.129 | –0.305 | –0.398 | –0.093 |
| C197 | –0.369 | –0.486 | –0.117 | –0.367 | –0.460 | –0.094 |
| sum | –0.916 | –1.316 | –0.400 | –0.910 | –1.205 | –0.295 |
| total cluster | –0.727 | –1.499 | –0.773 | –0.726 | –1.319 | –0.593 |
| OC4 | –0.334 | –0.309 | 0.025 | –0.333 | –0.328 | 0.006 |
| C3 | –0.010 | –0.016 | –0.006 | –0.013 | –0.038 | –0.025 |
| C2 | 0.019 | 0.049 | 0.030 | 0.026 | 0.068 | 0.042 |
| total HMBPP | –0.646 | –0.636 | 0.010 | –0.645 | –0.784 | –0.139 |
| cluster + HMBPP | –1.372 | –2.135 | –0.763 | –1.371 | –2.103 | –0.732 |
a
The difference in charge (Δq) between the oxidized and 1e– reduced atoms is indicated.