Experimental investigation of anion-π interactions--applications and biochemical relevance.

Anion-π interactions, intuitively repulsive forces, turned from controversial to a well-established non-covalent interaction over the past quarter of a century. Within this time frame the question "Anion-π interactions. Do they exist?" could be answered and even more importantly its functional relevance was proven. The present feature article summarizes the experimental findings of anion-π studies in the gas phase, solution and in the solid state and highlights the application of anion-π interactions in anion recognition, sensing and transport as well as in catalysis. Moreover, the biochemical relevance of this weak intermolecular force is comprehensively reviewed.