Anions should not interact with π electron clouds in aromatic molecules, but they do, usually when the molecule has a strong-electron withdrawing group.
Stefan Matile’s team, University of Geneva, Switzerland, have observed the interaction with electrospray tandem mass spectrometry. They analyzed a series of compounds of varying π -acidity to show that even under laser radiation an anion can remain coupled to a π electron cloud.
Anionic reaction intermediates are key to many organic syntheses, so finding ways to stabilize them on a π-acidic surface could lead to novel catalysts.
- Experimental evidence for the functional relevance of anion-π interactions
R. E. Dawson, A. Hennig, D. P. Weimann, D. Emery, V. Ravikumar, J. Montenegro, T. Takeuchi, S. Gabutti, M. Mayor, J. Mareda, C. A. Schalley, S. Matile
Nature Chem. 2010, Advance online publication, published 16 May 2010