title: Tetrakis(methylimidazole) and tetrakis(methylimidazolium) calix[4]arenes: competitive anion binding and deprotonation.
abstract: Neutral tetrakis(methylimidazole) (1) and the novel cationic tetrakis(methylimidazolium) (2) calixarenes have been prepared and their solid-state and solution behaviour examined. The neutral imidazole forms a mono-zwitterion at elevated temperature, a feature that has been observed both in solution and in the solid-state. The cationic imidazolium exhibits a range of hydrogen bond interactions with anions, with the titration curves upon binding to basic anions suggesting sequential binding to both the upper and lower rims.
authors.affiliation: School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.
authors.forename: Emma K
authors.initials: EK
authors.lastname: Bullough
authors.forename: Colin A
authors.initials: CA
authors.lastname: Kilner
authors.forename: Marc A
authors.initials: MA
authors.lastname: Little
authors.forename: Charlotte E
authors.initials: CE
authors.lastname: Willans
mesh_terms: D000838:Anions / Q000737:chemistry; D047250:Calixarenes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D007093:Imidazoles / Q000737:chemistry*; D008745:Methylation; D008958:Models, Molecular; D015394:Molecular Structure; D011522:Protons
chemical_list: D000838:Anions; D007093:Imidazoles; D011522:Protons; D047250:Calixarenes; C029899:imidazole