Self-assembled monolayers of oligophenylenecarboxylic acids on silver formed at the liquid-solid interface

Aitchison, Hannah and Lu, Hao and Hogan, Simon W. L. and Früchtl, Herbert and Cebula, Izabela and Zharnikov, Michael and Buck, Manfred (2016) Self-assembled monolayers of oligophenylenecarboxylic acids on silver formed at the liquid-solid interface. Langmuir. ISSN 0743-7463 (https://doi.org/10.1021/acs.langmuir.6b01773)

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Abstract

A series of para-oligophenylene mono- and dicarboxylic acids (R-(C6H4)nCOOH, n=1-3, R=H,COOH) was studied. Adsorbed on Au(111)/mica modified by an underpotential deposited bilayer of Ag, the self-assembled monolayers (SAMs) were analysed by near edge X-ray absorption fine structure spectroscopy, X-ray photoelectron spectroscopy and scanning tunneling microscopy. In all cases SAMs are formed with molecules adopting an upright orientation and anchored to the substrate by a carboxylate. Except benzoic acid, all SAMs could be imaged at molecular resolution, which revealed highly crystalline layers with a dense molecular packing. The structures of the SAMs are described by a rectangular (5×√3) unit cell for the prevailing phase of the monocarboxylic acids and an oblique (√93×√133) unit cell for the dicarboxylic acids, thus, evidencing a pronounced influence of the second COOH moiety on the SAM structure. Density functional theory calculations suggest that hydrogen bonding between the SAM terminating COOH moieties accounts for the difference. Contrasting other classes of SAMs, the systems studied here are determined by intermolecular interactions whereas molecule-substrate interactions play a secondary role. Thus, eliminating problems arising from the mismatch between the molecular and substrate lattices, coordinatively bonded carboxylic acids on silver should provide considerable flexibility in the design of SAM structures.

  • Item type:Article
    ID code:57567
    Dates:
    Date
    Event
    2 September 2016
    Published
    18 August 2016
    Accepted
    Notes:This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in Langmuir, copyright © American Chemical Society after peer review. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/acs.langmuir.6b01773
    Subjects:Science > Chemistry
    Department:Faculty of Engineering > Chemical and Process Engineering
    Depositing user: Pure Administrator
    Date deposited:29 Aug 2016 08:27
    Last modified:20 Apr 2024 14:12
    Related URLs:
    URI:https://strathprints.strath.ac.uk/id/eprint/57567
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