Crucial role of three-center hydrogen bonding in a challenging chiral molecular recognition.
The enantio-discrimination of beta-chiral primary ammonium ions is achieved by a rational approach that utilizes three-center (bifurcated) hydrogen bonding. The extraction experiments on various selected guests reveal that the bifurcated H-bonding plays a crucial role for the chiral discrimination. The X-ray data obtained for an inclusion complex substantiate such interactions. Using the bifurcated H-bonding, the chiral molecular recognition with our C(3)-symmetric tripodal oxazoline receptors is extended generally toward ammonium ions of alpha-, beta-, and alpha,beta-chiral amines. Simple molecular models, evoking the bifurcated H-bonding, explain the chiral discrimination modes.
Department of Chemistry and Center for Integrated Molecular Systems, Division of Molecular and Life Science, Pohang University of Science and Technology, San 31 Hyoja-dong, Pohang 790-784, South Korea.
Sung-Gon
SG
Kim
Kyung-Hyun
KH
Kim
Young Kook
YK
Kim
Seung Koo
SK
Shin
Kyo Han
KH
Ahn
D000588:Amines / Q000737:chemistry*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013237:Stereoisomerism
D000588:Amines; D000644:Quaternary Ammonium Compounds