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The Interaction Modes of Haloimidazolium Salts in Solution
Author(s) -
Schulz Nils,
Sokkar Pandian,
Engelage Elric,
Schindler Severin,
Erdelyi Mate,
SanchezGarcia Elsa,
Huber Stefan M.
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201705032
Subject(s) - chemistry , halogen bond , isothermal titration calorimetry , hydrogen bond , lewis acids and bases , moiety , steric effects , halogen , computational chemistry , cationic polymerization , molecular dynamics , non covalent interactions , molecule , stereochemistry , polymer chemistry , organic chemistry , alkyl , catalysis
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.