CH-anion versus anion-π interactions in the crystal and in solution of pentafluorobenzyl phosphonium salts
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Updated: Jun 7, 2026

From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Michael Müller1, Markus Albrecht, Johannes Sackmann
1Institut für Organische Chemie, RWTH Aachen, Landoltweg 1, 52074, Aachen, Germany.
Abstract:
A series of phosphonium salts with pentafluorobenzyl substituents have been synthesized and were investigated in the crystal as well as in solution. The solid state structures of 1a, 1b and 2d reveal the presence of anion-π as well as CH-anion interactions. The two attractive, yet competitive forces seem to act in concert and a directing effect of the CH interaction on the relative position between anion and π-system is observed. The search for anion-π interactions in solution failed. Only CH-anion interactions proved to be important in solution.
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