title: Guest-adaptable and water-stable peptide-based porous materials by imidazolate side chain control.
abstract: The peptide-based porous 3D framework, ZnCar, has been synthesized from Zn(2+) and the natural dipeptide carnosine (β-alanyl-L-histidine). Unlike previous extended peptide networks, the imidazole side chain of the histidine residue is deprotonated to afford Zn-imidazolate chains, with bonding similar to the zeolitic imidazolate framework (ZIF) family of porous materials. ZnCar exhibits permanent microporosity with a surface area of 448 m(2)  g(-1) , and its pores are 1D channels with 5 Å openings and a characteristic chiral shape. This compound is chemically stable in organic solvents and water. Single-crystal X-ray diffraction (XRD) showed that the ZnCar framework adapts to MeOH and H2 O guests because of the torsional flexibility of the main His-β-Ala chain, while retaining the rigidity conferred by the Zn-imidazolate chains. The conformation adopted by carnosine is driven by the H bonds formed both to other dipeptides and to the guests, permitting the observed structural transformations.
authors.affiliation: Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD (UK).
authors.forename: Alexandros P
authors.initials: AP
authors.lastname: Katsoulidis
authors.forename: Kyo Sung
authors.initials: KS
authors.lastname: Park
authors.forename: Dmytro
authors.initials: D
authors.lastname: Antypov
authors.forename: Carlos
authors.initials: C
authors.lastname: Martí-Gastaldo
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Miller
authors.forename: John E
authors.initials: JE
authors.lastname: Warren
authors.forename: Craig M
authors.initials: CM
authors.lastname: Robertson
authors.forename: Frédéric
authors.initials: F
authors.lastname: Blanc
authors.forename: George R
authors.initials: GR
authors.lastname: Darling
authors.forename: Neil G
authors.initials: NG
authors.lastname: Berry
authors.forename: John A
authors.initials: JA
authors.lastname: Purton
authors.forename: Dave J
authors.initials: DJ
authors.lastname: Adams
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Rosseinsky
keywords: imidazolates; metal-organic frameworks; microporous materials; peptides; structural adaptability