Single-Electron Transfer, S.E.T., and Charged Radicals

Single-electron transfer from an alkali metal such as lithium, sodium, or potassium is a common method of producing a radical anion. A radical anion has its extra electron in an antibonding orbital, which weakens the corresponding bonding orbital, and makes the radical anion more reactive than the neutral species. 

A radical cation can be chemically produced by single-electron transfer to commercially available stable amine radical cation salts. Again, the radical ion is more reactive than the neutral species. 

A Molecular Orbital Explanation of Single-Eiectron Transfer 

The formation of organomagnesiums is believed to occur by single-electron transfer that triggers the loss of the halide followed by a second single-electron transfer. 

The lowest unoccupied molecular orbital (LUMO) of R-L is usually the antibonding orbital of the C-L bond. When an electron is transferred into this LUMO, the result is 

---