Side-chain glycylglycine-based polymer for simultaneous sensing and removal of copper(II) from aqueous medium

Since glycylglycine (Gly-Gly) residue in the N-terminal region of human prion protein, a copper binding protein, binds with Cu(II), N-terminus Gly-Gly side-chain containing water soluble block copolymer was synthesized and used for simultaneous sensing and removal of Cu(II) ion from aqueous medium. The polymer has amide nitrogen atom and ester carbonyl group as potential binding sites in the side-chain Gly-Gly pendants. Job's plot experiment confirms 2:1 binding stoichiometry of polymer with Cu(II). This polymer is able to sense parts per billion level of Cu(II) very selectively in an aqueous medium and remove Cu(II) ions quantitatively by precipitating out the Cu(II) via complex formation in the pH range 7-9. The binding mode of polymer with Cu(II) in polymer-Cu(II) complex was characterized by H-1 NMR, FTIR, and UV-vis spectroscopy. The attachment of Cu(II) in the polymer-Cu(II) complex was confirmed by cyclic voltammetry experiment. Cu(II) release from the complex was achieved at pH 5 due to the protonation of amide nitrogen atoms in the Gly-Gly moiety. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 914-921