Conformational control of selectivity and stability in hybrid amide/urea macrocycles.
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.
Brooks
Simon J
SJ
School of Chemistry, University of Southampton, Southampton, SO171BJ United Kingdom.
García-Garrido
Sergio E
SE
Light
Mark E
ME
Cole
Pamela A
PA
Gale
Philip A
PA
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
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