Electrochemical and computational studies on intramolecular dissociative electron transfer in β-peptides

Jingxian Yu, David Huang, Joseph Shapter, Andrew Abell

    Research output: Contribution to journalArticle

    18 Citations (Scopus)

    Abstract

    The preparation of the β-peptides PCB-β3Val- β3Ala-β3Leu-NHC(CH3) 2OOtBu and PCB-(β3Val-β3Ala- β3Leu)2-NHC(CH3)2OOtBu, with a specific donor and acceptor at each terminus, is described. Circular dichroism, 2D NMR, and density functional theory calculations confirmed that PCB-(β3Val-β3Ala-β3Leu) 2-NHC(CH3)2OOtBu adopts a 14-helix conformation, whereas PCB-β3Val-β3Ala- β3Leu-NHC(CH3)2OOtBu has an ill-defined secondary structure. The electron-transfer rate constants in the two peptides were found to be 2580 and 9.8 s-1 respectively. Computational simulations based on Marcus theory coupled to constrained density functional theory provide clear theoretical evidence that different electron-transport pathways occur in the two peptides due to their different conformations: sequential hopping within PCB-(β3Val-β3Ala- β3Leu)2-NHC(CH3)2OOtBu and superexchange within PCB-β3Val-β3Ala- β3Leu-NHC(CH3)2OOtBu. Electron population analysis provides the first clear theoretical evidence that amide groups can act as hopping sites in long-range electron transfer.

    Original languageEnglish
    Pages (from-to)26608-26617
    Number of pages10
    JournalJournal of Physical Chemistry C
    Volume116
    Issue number50
    DOIs
    Publication statusPublished - 20 Dec 2012

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