The Interaction Modes of Haloimidazolium Salts in Solution.

Schulz N, Sokkar P, Engelage E, Schindler S, Erdelyi M, Sanchez-Garcia E, Huber SM

Chemistry 24 (14) 3464-3473 [2018-03-07; online 2017-12-28]

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.

Swedish NMR Centre (SNC) [Service]

PubMed 29160593

DOI 10.1002/chem.201705032

Crossref 10.1002/chem.201705032

Publications 9.5.0