title: Metal-complex assemblies constructed from the flexible hinge-like ligand H2bhnq: structural versatility and dynamic behavior in the solid state.
abstract: Novel metal-complex assemblies constructed from the flexible hinge-like ligand H(2)bhnq (H(2)bhnq=2,2'-bi(3-hydroxy-1,4-naphthoquinone)) have been synthesized. The X-ray crystal structures of these compounds reveal that four types of architectures are accessible by variation of the metal ions. In copper(II) compounds 1-3, the chelating bhnq(2-) ions bridge copper(II) centers to form one-dimensional zigzag chains. The chains of 1-3 are arranged by hydrogen-bonding interactions and stacking interactions to produce porous structures. Cobalt(II) and zinc(II) compounds 4 and 5 form one-dimensional helical chains. In 4 and 5, the crystal packing induces spontaneous resolution of the helical chains with chiral cavities formed perpendicular to the helices. Nickel(II) compounds 6 and 7 form cyclic tetramers. The fourth architecture, a dimer (compound 8), is obtained by the reaction of zinc(II) and bhnq(2-) in MeOH. In these compounds, changes of the dihedral angles and the metal-coordination mode of the bhnq(2-) ion induce the structural versatility. The assemblies of the zigzag chains of the copper(II) compounds exhibit reversible vapochromic behavior. UV/Vis, powder X-ray diffraction, EPR, and adsorption isotherm measurements indicate that this vapochromic behavior is based on the hinge-like flexibility of the bhnq(2-) ion.
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Yamada
authors.forename: Sadahiro
authors.initials: S
authors.lastname: Yagishita
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Tanaka
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Tohyama
authors.forename: Keiichi
authors.initials: K
authors.lastname: Adachi
authors.forename: Sumio
authors.initials: S
authors.lastname: Kaizaki
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kumagai
authors.forename: Katsuya
authors.initials: K
authors.lastname: Inoue
authors.forename: Ryo
authors.initials: R
authors.lastname: Kitaura
authors.forename: Ho-Chol
authors.initials: HC
authors.lastname: Chang
authors.forename: Susumu
authors.initials: S
authors.lastname: Kitagawa
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kawata
mesh_terms: D018360:Crystallography, X-Ray; D008024:Ligands; D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D009285:Naphthoquinones / Q000138:chemical synthesis*; D009942:Organometallic Compounds / Q000138:chemical synthesis*
chemical_list: C496351:2,2'-bi(3-hydroxy-1,4-naphthoquinone); D008024:Ligands; D008670:Metals; D009285:Naphthoquinones; D009942:Organometallic Compounds