title: Linear free energy relationships reveal structural changes in hydrogen-bonded host-guest interactions.
abstract: Hydrogen bond strength in host-guest systems is modulated by many factors including preorganization, steric effects, and electronic effects. To investigate how electronic effects impact barbiturate binding in bifurcated Hamilton receptors, a library of receptors with differing electronic substituents was synthesized and (1)H NMR titrations were performed with diethyl barbital. The Hammett plot revealed a clear break between the different electronic substituents suggesting a change in binding conformation. The titration data were complimented with computational studies confirming the change in structure.
authors.affiliation: Department of Chemistry and Biochemistry, Materials Science Institute, University of Oregon , Eugene, Oregon 97403-1253, United States.
authors.forename: Jacqueline M
authors.initials: JM
authors.lastname: McGrath
authors.forename: Michael D
authors.initials: MD
authors.lastname: Pluth
mesh_terms: D001463:Barbiturates / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D011725:Pyridines / Q000737:chemistry*
chemical_list: D001463:Barbiturates; D011725:Pyridines; C032232:barbituric acid