title: Tetra-armed cyclen bearing two benzo-15-crown-5 ethers in the side arms.
abstract: A tetra-armed cyclen bearing two benzo-15-crown-5 ethers in the side arms (1) is reported. When 1 equiv of Ag(+) is added to 1, the aromatic side arms cover the Ag(+) incorporated in the cyclen. Upon the addition of more than 1 equiv of Ag(+) to 1, the cyclen moiety binds Ag(+) first, before the crown ether in the side arms subsequently binds Ag(+). The log K11, log K12, and log K13 values for the 1:1, 1:2, and 1:3 (= 1/Ag(+)) complexes were estimated to be 9.4, 5.8, and 4.0, respectively. We found that the tetra-armed cyclen possessing crown ethers in the side arms behaves like an argentivorous molecule even though the crown ether arms bind metal cations.
authors.affiliation: Education Center, Faculty of Engineering, Chiba Institute of Technology , Shibazono 2-1-1, Narashino, Chiba 275-0023, Japan.
authors.forename: Mari
authors.initials: M
authors.lastname: Ikeda
authors.forename: Mikako
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Kuwahara
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Habata