title: Conformational control of selectivity and stability in hybrid amide/urea macrocycles.
abstract: The anion-binding properties of two similar hybrid amide/urea macrocycles containing either a 2,6-dicarboxamidophenyl or a 2,6-dicarboxamidopyridine group are compared. Significant differences in anion affinity and mode of interaction with anions are attributed to the presence of intramolecular hydrogen bonds in the pyridine system. In fact, remarkably, the phenyl macrocycle undergoes amide hydrolysis under neutral conditions in DMSO/water. The anion binding abilities of the receptors are compared to those of acyclic analogues of the macrocycles that show that the phenyl receptor behaves in a similar fashion to acyclic urea-containing receptors (i.e., showing little selectivity amongst oxo anions), whilst the pyridine-containing receptor shows a high affinity and selectivity for carboxylates.
authors.affiliation: School of Chemistry, University of Southampton, Southampton, SO171BJ United Kingdom.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Brooks
authors.forename: Sergio E
authors.initials: SE
authors.lastname: García-Garrido
authors.forename: Mark E
authors.initials: ME
authors.lastname: Light
authors.forename: Pamela A
authors.initials: PA
authors.lastname: Cole
authors.forename: Philip A
authors.initials: PA
authors.lastname: Gale
mesh_terms: D000577:Amides / Q000737:chemistry*; D000838:Anions; D001565:Benzoates / Q000737:chemistry; D001665:Binding Sites; D018360:Crystallography, X-Ray; D003998:Dicarboxylic Acids / Q000737:chemistry; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D006860:Hydrogen Bonding; D006868:Hydrolysis; D047028:Macrocyclic Compounds / Q000737:chemistry*; D008956:Models, Chemical; D008968:Molecular Conformation; D010848:Picolinic Acids / Q000737:chemistry; D014508:Urea / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D000577:Amides; D000838:Anions; D001565:Benzoates; D003998:Dicarboxylic Acids; D047028:Macrocyclic Compounds; D010848:Picolinic Acids; D014867:Water; D014508:Urea; C004860:dipicolinic acid; D004121:Dimethyl Sulfoxide