Large Enhancement of the Single-Molecular Conductance of a Molecular Wire through a Radical Substituent |
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Authors: | Ryuto Yasui Dr Daiki Shimizu Prof Kenji Matsuda |
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Institution: | Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, 615-8510 Japan |
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Abstract: | The single-molecular conductance between two π-conjugated wires with and without a radical substituent has been compared. Specifically, methyl- and iminonitroxide-substituted 4-(biphenyl-4-yl)pyridine wires bound onto a porphyrin template were subjected to scanning tunneling microscopy (STM) apparent-height measurement at the interface between highly oriented pyrolytic graphite (HOPG) and octan-1-oic acid. Statistical analysis of the STM images revealed that the radical-substituted wire has 3.2±1.7-fold higher conductance than the methyl-substituted reference. Although density functional theory (DFT) calculation suggests that only 17 % of the SOMO is distributed on the wire moiety, the effect was significant. This study presents the potential of radical substituents to achieve high conductivity in molecular wires. |
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Keywords: | molecular conductance radicals scanning tunneling microscopy nitroxides molecular electronics |
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