title: Side Arm Effects on Cyclen-Alkali Metal Cation Complexation: Highly Selective and Three-Dimensional Encapsulation of Na(+) Ion.
abstract: A variety of armed cyclens were prepared in which ester, amide, nitrile, and pyridine moieties were attached as cation-ligating side arms to a 12-membered ring. Ester-, amide-, and pyridine-armed cyclens nicely accommodated a Na(+) ion in a three-dimensional fashion and clearly discriminated the cation from Li(+) and K(+) ions. They extracted Na(+) ion more efficiently and selectively than common Na(+) ion-selective ligands. X-ray diffraction, FAB-MS, (23)Na NMR binding studies, and computer modeling experiments demonstrated that the cyclens having ester-, amide-, and pyridine-functionalized side arms formed highly selective encapsulated Na(+) complexes via a cooperative action of parent cyclen and side arms.
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan, and Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering, Yamaguchi University, Ube 755-0031, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsukube
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Mizutani
authors.forename: Satoshi
authors.initials: S
authors.lastname: Shinoda
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Okazaki
authors.forename: Makoto
authors.initials: M
authors.lastname: Tadokoro
authors.forename: Kenzi
authors.initials: K
authors.lastname: Hori