Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K.
Department of Chemistry, Physical & Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, U.K.
J Am Chem Soc. 2022 May 18;144(19):8827-8836. doi: 10.1021/jacs.2c02924. Epub 2022 May 6.
Inspired by the success of its related sigma-hole congener halogen bonding (XB), chalcogen bonding (ChB) is emerging as a powerful noncovalent interaction with a plethora of applications in supramolecular chemistry and beyond. Despite its increasing importance, the judicious modulation of ChB donor strength remains a formidable challenge. Herein, we present, for the first time, the reversible and large-scale modulation of ChB potency by electrochemical redox control. This is exemplified by both the switching-ON of anion recognition via ChB oxidative activation of a novel bis(ferrocenyltellurotriazole) anion host and switching-OFF reductive ChB deactivation of anion binding potency with a telluroviologen receptor. The direct linking of the redox-active center and ChB receptor donor sites enables strong coupling, which is reflected by up to a remarkable 3 orders of magnitude modulation of anion binding strength. This is demonstrated through large voltammetric perturbations of the respective receptor ferrocene and viologen redox couples, enabling, for the first time, ChB-mediated electrochemical anion sensing. The sensors not only display significant anion-binding-induced electrochemical responses in competitive aqueous-organic solvent systems but can compete with, or even outperform similar, highly potent XB and HB sensors. These observations serve to highlight a unique (redox) tunability of ChB and pave the way for further exploration of the reversible (redox) modulation of ChB in a wide range of applications, including anion sensors as well as molecular switches and machines.
受相关 sigma 孔型卤键 (XB) 成功的启发，硫属键 (ChB) 作为一种强大的非共价相互作用正在兴起，在超分子化学等领域有广泛的应用。尽管 ChB 越来越重要，但明智地调节 ChB 供体强度仍然是一个艰巨的挑战。在此，我们首次展示了通过电化学氧化还原控制来可逆且大规模地调节 ChB 强度。这通过新型双(二茂铁基碲三唑)阴离子主体的 ChB 氧化激活来实现阴离子识别的开启，以及通过还原型 ChB 失活来关闭阴离子结合强度的实例得到了证明。氧化还原活性中心和 ChB 受体供体位点的直接连接实现了强耦合，这反映在阴离子结合强度的调节幅度高达 3 个数量级。这通过相应受体二茂铁和紫精氧化还原对的大伏安扰动来证明，首次实现了 ChB 介导的电化学阴离子传感。这些传感器不仅在竞争的水-有机溶剂体系中显示出显著的阴离子结合诱导的电化学响应，而且可以与甚至超过类似的、高活性的 XB 和 HB 传感器相竞争。这些观察结果突出了 ChB 的独特（氧化还原）可调性，并为进一步探索 ChB 在广泛应用中的可逆（氧化还原）调节铺平了道路，包括阴离子传感器以及分子开关和机器。
