Electrochemically Mediated Au–C(sp 2 ) Anchors for Molecular Electronics

作者：Rajarshi Samajdar, Hao Yang, Seungjoo Yi, Chun-I Wang, Seth T. Putnam, Michael A. Pence, Gavin S. Lindsay, Moeen Meigooni, Xiaolin Liu, Junjiang Ren, Jeffrey S. Moore, Emad Tajkhorshid, Andrew A. Gewirth, Joaquín Rodríguez‐López, Nicholas E. Jackson, Charles M. Schroeder · 发表于：The Journal of Physical Chemistry C · 年份：2025 · DOI：10.1021/acs.jpcc.5c06124 · 被引用次数：3 · 研究领域：Molecular Junctions and Nanostructures、Semiconductor materials and devices、Electrocatalysts for Energy Conversion

Terminal anchor groups play a key role in the stability and electronic properties of molecular junctions. Single molecule junctions typically consist of two preinstalled terminal anchors linking organic molecules to metal electrodes. Here, we show that p -terphenyl derivatives containing only a single terminal anchor show conductance features similar to junctions with two preinstalled terminal anchors. A set of p -terphenyl derivatives with one terminal anchor was prepared using automated chemical synthesis and characterized using single molecule electronics experiments, molecular dynamics (MD) simulations, bulk electrochemistry and spectroscopy, and nonequilibrium Green’s function-density functional theory (NEGF-DFT) calculations. Our results show that 4-amino- p -terphenyl (PPP) and related analogs exhibit a well-defined high conductance state that is diminished or absent in other p -terphenyl derivatives lacking a preinstalled amine terminal anchor or fluorine or methyl substitutions at the terminal para position. However, a low conductance state is observed in all amino- p -terphenyl derivatives with one preinstalled anchor due to molecular junctions formed by noncovalent dimeric π–π stacking interactions. The observed high conductance state diminishes upon the addition of reducing agents and is restored upon the addition of an oxidizing agent. Our results suggest that the high conductance state arises due to Au–C(sp 2 ) bond formation facilitated by a single electron oxi...