IoE Center of Molecular Architecture, Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India.
Chemistry. 2023 Jun 13;29(33):e202300891. doi: 10.1002/chem.202300891. Epub 2023 Apr 17.
Selective binding of chloride over the other most abundant anions in living organisms is pivotal due to its essential role in physiological functions. Herein, we report a template-free Pd L cage exhibiting high selectivity for medium-sized halides (i. e., Cl , Br ) in water owing to the size-discriminatory nature of the cage cavity. In pure water, this cage displays high selectivity and micromolar affinity for chloride. The cage shows no binding towards other biologically more abundant essential anions such as phosphates, carboxylates, or bicarbonate. This cage shows an unprecedented nanomolar affinity with 1 : 1 binding stoichiometry for chloride in aqueous-DMSO media. This high affinity was achieved with the best use of traditional hydrogen bonding and electrostatic interactions, as confirmed by single-crystal X-ray diffraction analysis. This well-defined cage sequestrates F by cleaving a B-F bond in BF in a facile manner in a nonpolar solvent or in the presence of excess ligand. This cage also demonstrates capture of the sub-ppm chloride level that is present in commercial D O samples.
由于氯离子在生理功能中的重要作用，其对生物体中其他最丰富的阴离子的选择性结合是至关重要的。在此，我们报告了一种无模板的 Pd L 笼，由于笼腔的尺寸选择性，它在水中对中体型卤化物（即 Cl-、Br-）表现出高选择性。在纯水中，该笼对氯离子表现出高选择性和微摩尔亲和力。该笼对其他在生物体内更丰富的必需阴离子（如磷酸盐、羧酸盐或碳酸氢盐）没有结合作用。该笼在水-DMSO 介质中对氯离子表现出前所未有的纳摩尔亲和力，具有 1:1 的结合化学计量比。这种高亲和力是通过传统氢键和静电相互作用的最佳利用实现的，这一点通过单晶 X 射线衍射分析得到了证实。这个结构明确的笼子可以通过在非极性溶剂中或在过量配体存在下，很容易地在 BF3 中切断 B-F 键，从而将 F 捕获。该笼还可以捕获商业 D2O 样品中存在的亚 ppm 级别的氯离子。
