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Issue 40, 2012
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Electronic transport and mechanical stability of carboxyl linked single-molecule junctions

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Abstract

We characterize electron transport across Au–molecule–Au junctions of heterogeneous carboxyl and methyl sulfide terminated saturated and conjugated molecules. Low-bias conductance measurements are performed using the scanning tunneling microscopy based break-junction technique in the presence of solvents and at room temperature. For a series of alkanes with 1–4 carbon atoms in the hydrocarbon chain, our results show an exponential decrease in conductance with increasing molecule length characterized by a decay constant of 0.9 ± 0.1 per methylene group. Control measurements in pH 11 solutions and with COOMe terminations suggest that the carboxylic acid group binds through the formation of a COO–Au bond. Simultaneous measurements of conductance and force across these junctions yield a rupture force of 0.6 ± 0.1 nN, comparable to that required to rupture a Au–SMe bond. By establishing reliable, in situ junction formation, these experiments provide a new approach to probe electronic properties of carboxyl groups at the single molecule level.

Graphical abstract: Electronic transport and mechanical stability of carboxyl linked single-molecule junctions

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Publication details

The article was received on 16 May 2012, accepted on 09 Jul 2012 and first published on 09 Jul 2012


Article type: Paper
DOI: 10.1039/C2CP41578J
Citation: Phys. Chem. Chem. Phys., 2012,14, 13841-13845
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    Electronic transport and mechanical stability of carboxyl linked single-molecule junctions

    S. Ahn, S. V. Aradhya, R. S. Klausen, B. Capozzi, X. Roy, M. L. Steigerwald, C. Nuckolls and L. Venkataraman, Phys. Chem. Chem. Phys., 2012, 14, 13841
    DOI: 10.1039/C2CP41578J

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