Samarium Diiodide Acting on Acetone-Modeling Single Electron Transfer Energetics in Solution
Luca Steiner1,2, Andreas J Achazi3, Bess Vlaisavljevich4
1Institute of Physical und Theoretical Chemistry, NAWI Graz, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria.
Molecules (Basel, Switzerland)
|December 23, 2022
Summary
Samarium diiodide (SmI2) is a single electron transfer agent. Computational chemistry reveals the electron transfer from SmI2 to acetone is endothermic, contrary to common assumptions.
Area of Science:
- Organic Chemistry
- Computational Chemistry
- Physical Chemistry
Background:
- Samarium diiodide (SmI2) is widely used as a single electron transfer (SET) reagent in organic synthesis.
- Lewis structures suggest SmI2 binding to carbonyl groups forms a ketyl radical, implying facile electron transfer.
Purpose of the Study:
- To computationally investigate the mechanism of electron transfer from samarium diiodide to a carbonyl group, specifically acetone.
- To verify the electronic structure changes upon SmI2 binding to carbonyls.
Main Methods:
- All-electron CASPT2 calculations incorporating scalar relativistic effects were employed.
- PBE0-D3(BJ) functional with a small core pseudopotential was used for energy calculations and comparison.
Main Results:
- Computational results predict an endothermic electron transfer from samarium diiodide to acetone.
- Calculated energies align well with CASPT2 results, supporting the endothermicity.
- The study confirms the experimentally observed enhancement of SmI2 reduction potential by hexamethylphosphoramide (HMPA).
Conclusions:
- The common assumption of facile ketyl radical formation via exothermic electron transfer from SmI2 to carbonyls is challenged.
- Computational data provides a deeper understanding of SmI2's electronic behavior in organic reactions.
- The findings are consistent with experimental observations regarding SmI2 reduction potential modulation by additives like HMPA.
Keywords:
HMPA influencecomputational chemistrydensity functional theoryeffective core potentialketyl radicallanthanoide chemistryreduction potentialMore Related Videos
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