Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.
Université Paris-Saclay, ENS Paris-Saclay, CNRS, PPSM, 4 avenue des Sciences, 91190 Gif/Yvette, France.
J Am Chem Soc. 2021 Feb 24;143(7):2886-2895. doi: 10.1021/jacs.0c12664. Epub 2021 Feb 12.
The charge transport in single-molecule junctions depends critically on the chemical identity of the anchor groups that are used to connect the molecular wires to the electrodes. In this research, we report a new anchoring strategy, called the electrostatic anchor, formed through the efficient Coulombic interaction between the gold electrodes and the positively charged pyridinium terminal groups. Our results show that these pyridinium groups serve as efficient electrostatic anchors forming robust gold-molecule-gold junctions. We have also observed binary switching in dicationic viologen molecular junctions, demonstrating an electron injection-induced redox switching in single-molecule junctions. We attribute the difference in low- and high-conductance states to a dicationic ground state and a radical cationic metastable state, respectively. Overall, this anchoring strategy and redox-switching mechanism could constitute the basis for a new class of redox-activated single-molecule switches.
单分子结中的电荷输运取决于将分子导线与电极连接的锚定基团的化学性质。在这项研究中，我们报告了一种新的锚定策略，称为静电锚定，它是通过金电极与带正电荷的吡啶端基之间的有效库仑相互作用形成的。我们的结果表明，这些吡啶基团作为有效的静电锚定，形成了坚固的金-分子-金结。我们还观察到二价阳离子化 viologen 分子结中的双态开关，证明了单分子结中的电子注入诱导的氧化还原开关。我们将低电导率和高电导率状态的差异归因于二价阳离子基态和自由基阳离子亚稳态。总的来说，这种锚固策略和氧化还原开关机制可能为一类新的氧化还原激活的单分子开关奠定基础。
