title: Wide-ranging host capability of a Pd(II)-linked M2L4 molecular capsule with an anthracene shell.
abstract: This article reports that an M2L4 molecular capsule is capable of encapsulating various neutral molecules in quantitative yields. The capsule was obtained as a single product by mixing a small number of components; two Pd(II) ions and four bent bispyridine ligands containing two anthracene panels. Detailed studies of the host capability of the Pd(II)-linked capsule revealed that spherical (e.g., paracyclophane, adamantanes, and fullerene C60), planar (e.g., pyrenes and triphenylene), and bowl-shaped molecules (e.g., corannulene) were encapsulated in the large spherical cavity, giving rise to 1:1 and 1:2 host-guest complexes, respectively. The volume of the encapsulated guest molecules ranged from 190 to 490 Å(3). Within the capsule, the planar guests adopt a stacked-dimer structure and the bowl-shaped guests formed an unprecedented concave-to-concave capsular structure, which are fully shielded by the anthracene shell. Competitive binding experiments of the capsule with a set of the planar guests established a preferential binding series for pyrenes≈phenanthrene>triphenylene. Furthermore, the capsule showed the selective formation of an unusual ternary complex in the case of triphenylene and corannulene.
authors.affiliation: Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
authors.forename: Norifumi
authors.initials: N
authors.lastname: Kishi
authors.forename: Zhiou
authors.initials: Z
authors.lastname: Li
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Sei
authors.forename: Munetaka
authors.initials: M
authors.lastname: Akita
authors.forename: Kenji
authors.initials: K
authors.lastname: Yoza
authors.forename: Jay S
authors.initials: JS
authors.lastname: Siegel
authors.forename: Michito
authors.initials: M
authors.lastname: Yoshizawa