Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008, United States.
Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States.
Inorg Chem. 2022 Jun 13;61(23):8611-8622. doi: 10.1021/acs.inorgchem.2c01198. Epub 2022 May 26.
The previously unexplored noncovalent binding of the highly toxic tetrafluoroberyllate anion (BeF) and its extraction from water into organic solvents are presented. Nanojars resemble anion-binding proteins in that they also possess an inner anion binding pocket lined by a multitude of H-bond donors (OH groups), which wrap around the incarcerated anion and completely isolate it from the surrounding medium. The BeF-binding propensity of [BeF⊂{Cu(OH)(pz)}] (pz = pyrazolate; = 27-32) nanojars of different sizes is investigated using an array of techniques including mass spectrometry, paramagnetic H, Be, and F NMR spectroscopy, and X-ray crystallography, along with thermal stability studies in solution and chemical stability studies toward acidity and Ba ions. The latter is found to be unable to precipitate the insoluble BaBeF from nanojar solutions, indicating a very strong binding of the BeF anion by nanojars. Be and F NMR spectroscopy allows for the unprecedented direct probing of the incarcerated anion in a nanojar and, along with H NMR studies, reveals the fluxional structure of nanojars and their inner anion-binding pockets. Single-crystal X-ray diffraction provides the crystal and molecular structures of (BuN)[BeF⊂{Cu(OH)(pz)}], which contains a novel Cu-ring combination ( = 9 + 14 + 9), (BuN)[BeF⊂{Cu(OH)(pz)}], and (BuN)[BeF⊂{Cu(OH)(pz)}] and offers detailed structural parameters related to the supramolecular binding of BeF in these nanojars. The extraction of BeF from water into organic solvents, including the highly hydrophobic solvent -heptane, demonstrates that nanojars are efficient binding and extracting agents not only for oxoanions but also for fluoroanions.
先前未被探索的高毒性四氟硼酸根阴离子（BeF）的非共价结合及其从水中萃取到有机溶剂中，本文进行了介绍。纳米罐在某种程度上类似于阴离子结合蛋白，因为它们也具有一个由多个氢键供体（OH 基团）组成的内部阴离子结合口袋，这些基团包裹着被囚禁的阴离子，并将其完全与周围介质隔离。使用一系列技术，包括质谱、顺磁 H、Be 和 F NMR 光谱以及 X 射线晶体学，以及在溶液中的热稳定性研究和对酸度和 Ba 离子的化学稳定性研究，研究了不同尺寸的 [BeF⊂{Cu(OH)(pz)}]（pz = 吡唑； = 27-32）纳米罐对 BeF 结合的倾向性。后者发现无法将难溶的 BaBeF 从纳米罐溶液中沉淀出来，这表明纳米罐对 BeF 阴离子具有很强的结合能力。Be 和 F NMR 光谱可用于对纳米罐中被囚禁的阴离子进行前所未有的直接探测，与 H NMR 研究一起，揭示了纳米罐及其内部阴离子结合口袋的结构动态性。单晶 X 射线衍射提供了（BuN）[BeF⊂{Cu(OH)(pz)}]的晶体和分子结构，其中包含一种新颖的 Cu 环组合（ = 9 + 14 + 9），（BuN）[BeF⊂{Cu(OH)(pz)}]，和（BuN）[BeF⊂{Cu(OH)(pz)}]，并提供了与这些纳米罐中 BeF 超分子结合相关的详细结构参数。BeF 从水中萃取到有机溶剂中，包括高度疏水性溶剂 -heptane，证明纳米罐不仅是氧阴离子，而且还是氟阴离子的有效结合和萃取剂。
