title: Ni(II)-mediated self-assembly of artificial beta-dipeptides forming a macrocyclic tetranuclear complex with interior spaces for in-line molecular arrangement.
abstract: Metal-mediated self-assembly of bioinspired molecular building blocks shows promise as an excellent strategy to provide well-defined metal arrays and nanoscopic metallo-architectures in a programmable way. Herein, we report Ni(II)-mediated self-assembly of artificial beta-dipeptides (1) which were prepared from a newly designed beta-amino acid bearing a propanediamine ligand as the side chain. The beta-dipeptide (1) has thus two sets of ligands, that is, each building block serves as a tridentate ligand with a bidentate propanediamine unit and an amide carbonyl group. Both C- and N-terminal tridentate ligands in 1 bind to two Ni(II) ions independently, and consequently, four beta-dipeptides are circularly arranged in a head-to-tail fashion to form a macrocyclic tetranuclear Ni(II) complex, Ni414(ClO4)8(H2O)10. The cyclic structure was determined by X-ray analysis and ESI-TOF mass spectrometry. The resulting unique twisted-boat structure allows the formation of isolated spaces for in-line hydrogen-bonded arrangement of water and anion molecules within a hole and two grooves rich in hydrogen bonding groups.
authors.affiliation: Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Miyake
authors.forename: Shohei
authors.initials: S
authors.lastname: Tashiro
authors.forename: Motoo
authors.initials: M
authors.lastname: Shiro
authors.forename: Kentaro
authors.initials: K
authors.lastname: Tanaka
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Shionoya
mesh_terms: D002413:Cations, Divalent / Q000737:chemistry; D018360:Crystallography, X-Ray; D004151:Dipeptides / Q000737:chemistry*; D006860:Hydrogen Bonding; D008956:Models, Chemical; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D002413:Cations, Divalent; D004151:Dipeptides; D009942:Organometallic Compounds; D009532:Nickel