The Cation−π Interaction in Chemistry and Biology

The cation-π interaction is an important noncovalent binding force that impacts all areas of chemistry and biology. Extensive computational and gas phase experimental studies have established the potential strength and the essential nature of the interaction. Previous reviews have emphasized studies of model systems and a variety of biological examples. This work includes discussion of those areas but emphasizes other areas that are perhaps less well appreciated. These include the novel cation-π binding ability of alkali metals in water; the application of the cation-π interaction to organic synthesis and chemical biology; cooperative behaviors of multiple cation-π interactions, including adhesive proteins from mussels and similar organisms and the formation and modulation of biomolecular condensates (phase separation); and cation-π interactions involved in recognizing DNA/RNA.