In the review 'Energy transfer catalysis mediated by visible light: principles, applications, directions' (doi.org/10.1039/c8cs00054a) they talk about identifying the difference between electron transfer and energy transfer in different ways, the last of which: 'experimental or theoretical redox potential determination can also be used to exclude electron transfer processes and thus provide indirect evidence of a sensitization mechanism'.
How can one use the redox potentials obtained from a cyclic voltammogram to determine whether a photocatalyst undergoes an energy transfer mechanism and not a photoredox mechanism?
Dear Francis Bru ,
This is a very fundamental question in photochemistry. As you probably know :
- Dexter mechanism, involved for exemple in triplet-triplet annihilation, is one type of energy transfer. And at closer look and generally represented, this mechanism involves reciprocal electronic transfer !
- The electron when added or removed to or from a molecule changes the energy of the molecule: can we talk about energy transfer also when transferring electron because of these modifications?!
I cannot directly answer your question but could decipher what the authors wanted to say: the sentence might seem to say that, if the redox potentials of your molecule, compared to your photoredox catalyst doesn't match, but, the given reaction occurs anyway, energy transfer might be involved.
This is well discussed in this publication of Yoon for example:
Article Enantioselective photochemistry through Lewis acid–catalyzed...
And also in those very interesting publications, where, it might be, even when redox potentials not matching... A discussion on redox-mediated reactions.
Article Excited-state properties of a triply ortho-metalated iridium...
Article Visible-Light-Induced Photocatalytic Reductive Transformatio...
Article ChemInform Abstract: Photocatalytic Hydrodefluorination: Fac...
The question is still opened and I could also suggest you to have a look on this publication:
Article Photosensitization and Photocatalysis - Perspectives in Orga...
Hope this could help you!
both electron transfer and energy transfer may be occures under condition
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