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 (?-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-?-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.

SUBMITTER: Katsoulidis AP 

PROVIDER: S-EPMC3995008 | biostudies-other | 2014 Jan

REPOSITORIES: biostudies-other