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Abstract

We performed a comparative study on the interaction modes of 2‐haloimidazolium salts with anions in solution, particularly with regard to halogen bonding, hydrogen bonding and anion–π interactions. The syntheses and solid‐state analyses of a series of sterically and electronically modified 2‐haloimidazolium structures are presented. Detailed isothermal titration calorimetry (ITC) measurements, quantum mechanics/molecular mechanics (QM/MM), classical molecular dynamics simulations (MD) and free‐energy calculations together with NMR spectroscopy were used to elucidate the binding modes in solution. Our work reveals the absence of a potential anion–π interaction between the cationic imidazolium ring and the Lewis basic counteranion, and corroborates a formation of halogen bonding via the Lewis acidic iodine moiety and hydrogen bonding via the backbone hydrogen atoms, with repercussions in the field of organocatalysis.