title: Guest shape-responsive fitting of porous coordination polymer with shrinkable framework.
abstract: In situ synchrotron X-ray powder diffraction patterns of porous coordination polymers [[Cu(2)(pzdc)(2)(bpy)].G] have been measured (pzdc = pyrazine-2,3-dicarboxylate, bpy = 4,4'-bipyridine) (where G = H(2)O for CPL-2 superset H(2)()O, G = benzene for CPL-2 superset benzene, and G = void for the apohost). The structures of apohost and CPL-2 superset benzene were determined from Rietveld analysis. Adsorption of benzene in the channels induced a remarkable contraction in the crystal (b axis; 6.8%, volume; 4.9%), although the channels were occupied by the benzene molecules. This crystal transformation provides a new pore structure that is well suited for benzene molecules, and we denote it as a "shape-responsive fitting" transformation. This type of pore gives rise to a new guideline: frameworks can be composed of flexible motifs that are linked via strong bond and/or stiff motifs that are connected via weaker bonds.
authors.affiliation: Department of Synthetic Chemistry and Biological Chemistry, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Ryotaro
authors.initials: R
authors.lastname: Matsuda
authors.forename: Ryo
authors.initials: R
authors.lastname: Kitaura
authors.forename: Susumu
authors.initials: S
authors.lastname: Kitagawa
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Kubota
authors.forename: Tatsuo C
authors.initials: TC
authors.lastname: Kobayashi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Horike
authors.forename: Masaki
authors.initials: M
authors.lastname: Takata