0000000000180407
AUTHOR
Katharina Wiemer
Weak Intermolecular Anion–π Interactions in Pentafluorobenzyl-Substituted Ammonium Betaines
A series of ammonium–carboxylate and ammonium–sulfonate betaines was synthesized and studied by single-crystal X-ray diffraction analysis to investigate the weak intermolecular interactions as well as the intramolecular interactions in the solid state. None of the expected intramolecular anion–π interactions could be observed, probably because of the steric demands and the reduced nucleophilicity of the anionic part of the betaines. Nevertheless, a weak intermolecular anion–π interaction between the anionic part of the betaine and the pentafluorophenyl unit is present in the structure of 5a.
Controlling the position of anions relative to a pentafluorophenyl groupw
The position of an anion above an electron-deficient arene can be controlled by the geometry of appended directing groups. Here a series of ammonium substituted pentafluorophenyl derivatives is investigated. The presented results are one step on the way to find the ideal structural features for an effective and superior receptor for anion–π studies.