Internal Oriented Electric Fields as a Strategy for Selectively Modifying Photochemical Reactivity

Nicholas S. Hill, Michelle L. Coote

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


Time-dependent density functional theory calculations have been performed on acetophenone derivatives to explore the possibility of using charged functional groups as internal electric fields, the orientation of which can be altered to change photochemical behavior at will. Results demonstrate that nonconjugated charged groups can significantly alter, by up to -1.44 eV, the stabilities of excited states. Specifically, a nonconjugated negatively charged group in the para position will destabilize the nπ∗ and stabilize the π π∗ transitions, while a positively charged group will do the opposite. These electrostatic effects can be tuned by moving these substituents into the meta and ortho positions. Through use of acids and bases, these charged groups can be switched on or off with pH, allowing for selective alteration of the energy levels and photochemical reactivity. Solvent effects are shown to attenuate the electric field effect with increasing dielectric permittivity; however electrostatic effects are shown to remain significant even in quite polar solvents. Using charged functional groups to deliver the position-dependent electrostatic (de)stabilization effects is therefore a potential route to improving the efficiency of desirable photochemical processes.

Original languageEnglish
Pages (from-to)17800-17804
Number of pages5
JournalJournal of The American Chemical Society
Issue number50
Publication statusPublished - 19 Dec 2018
Externally publishedYes


  • Electric fields
  • Electrostatics
  • Solvents
  • Phase transitions
  • Excited states


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