The energies of a molecule’s Highest Occupied Molecular Orbital’s (HOMO’s) and the Lowest Unoccupied Molecular Orbitals (LUMO’s) tell us alot about that molecules reactivity. In general, molecules with high HOMO’s are good nucleophiles, bases, and reductants while molecules with low LUMO’s are good electrophiles, Lewis acids and oxidants. Unfortunately, the absolute magnitudes of “high” or “low” are very rarely treated. In the figure above, we plotted absolute values of HOMO and LUMO energies to convey more of a global understanding of reactivity trends.
- Fu, Y.; Liu, L.; Yu, H.Z.; Wang, Y.M.; Guo, Q.X. J. Am. Chem. Soc, 2005, 127, 7227-7234.