Redox potentials measure how easy or hard it is to add or remove electrons from an atom. To remember the difference between reduction and oxidation, you can use “OIL RIG”: Oxidation Is Loss (of electrons) and Reduction Is Gain (of electrons).
Rowan's redox potential prediction workflow predicts the reduction and/or oxidation potential of a molecule by computing the energy difference between the reduced/oxidized and starting state of the molecule.
Rowan optimizes the neutral, oxidized, and reduced structures by running multistage optimizations, adding a solvent correction to each.
When the workflow is finished, Rowan lets you view the reduction and oxidation potentials relative to different reference electrodes, using conversion constants from Pavlishchuk and Addison.
On the OROP benchmark set, Rowan's redox potential prediction workflow (in rapid mode) displays a mean absolute error of 0.32 V (excluding a few values that don't start from a neutral species or aren't in acetonitrile).
Rowan's redox potential prediction workflow can be run in four modes: reckless, rapid, careful, or meticulous. Here's what selecting each mode tunes:
| Mode | Opt 1 | Opt 2 | Single Point |
|---|---|---|---|
| Reckless | GFN-FF | GFN2-xTB | |
| Rapid | GFN2-xTB | r²SCAN-3c | |
| Careful | r²SCAN-3c | ωB97X-3c | |
| Meticulous | r²SCAN-3c | ωB97X-3c | ωB97M-D3BJ/def2-TZVPPD |