The Orbital Energy Landscape

It is incredibly helpful to translate reduction potentials into what they actually represent: orbital energies.

When we apply a negative potential (reduction), we are essentially pumping electrons into the lowest unoccupied molecular orbital (LUMO). When we apply a positive potential (oxidation), we are ripping electrons out of the highest occupied molecular orbital (HOMO).

Visualizing potentials this way helps predict reactivity and troubleshoot side reactions. For example, if you are trying to do a deep reduction but your solvent has a lower-energy LUMO than your substrate, the solvent will steal the electrons and decompose. Similarly, knowing where a sacrificial donor's HOMO sits helps you choose the right reagent to drive your anodic reaction forward without over-oxidizing your product.

Interactive Orbital Energy Landscape

A mapping of standard redox potentials to approximate HOMO and LUMO energies.

Lab Notes

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N/A

-- V

vs --

Select an energy level on the canvas or use the dropdown to review specific molecular properties.

Source: Izutsu, K. Electrochemistry in Nonaqueous Solutions, 2nd Ed. Wiley-VCH, 2010. Tables 8.5 & 8.7.
Note: In electrochemistry, more negative potentials correspond to higher electron energies (plotted UP).

Frontier Orbital Potentials

Compound	Type	Potential (V)	Reference

Red bars indicate oxidations (HOMO), and blue bars indicate reductions (LUMO). You can click on the energy levels or use the dropdown to explore how different functional groups shift these energies.