title: Relative binding affinities of alkali metal cations to
abstract: The binding affinity and selectivity of a new ionophore, [1(8)]starand (1), toward alkali metal cations in methanol were examined through NMR titration experiments and free energy perturbation (FEP) and molecular dynamics simulations. The preference was determined to be K(+) > Rb(+) > Cs(+) > Na(+) >> Li(+) in both FEP simulations and NMR experiments. The FEP simulation results were able to predict the relative binding free energies with errors less than 0.13 kcal/mol, except for the case between Li(+) and Na(+). The cation selectivity was rationalized by analyzing the radial distribution functions of the M-O and M-C distances of free metal cations in methanol and those of metal-ionophore complexes in methanol.
authors.affiliation: Department of Chemistry, Seoul National University, Seoul 151-742, Korea.
authors.initials: S
authors.lastname: Hwang
authors.initials: KH
authors.lastname: Lee
authors.initials: GH
authors.lastname: Ryu
authors.initials: YH
authors.lastname: Jang
authors.initials: SB
authors.lastname: Lee
authors.initials: WY
authors.lastname: Lee
authors.initials: JI
authors.lastname: Hong
authors.initials: DS
authors.lastname: Chung