Artificial molecular machines have captured the full attention of the scientific community since Jean-Pierre Sauvage, Fraser Stoddart, and Ben Feringa were awarded the 2016 Nobel Prize in Chemistry. The past and current developments in molecular machinery (rotaxanes, rotors, and switches) primarily rely on organic-based compounds as molecular building blocks for their assembly and future development. In contrast, the main group chemical space has not been traditionally part of the molecular machine domain. The oxidation states and valency ranges within the p-block provide a tremendous wealth of structures with various chemical properties. Such chemical diversity─when implemented in molecular machines─could become a transformative force in the field. Within this context, we have rationally designed a series of NH-bridged acyclic dimeric cyclodiphosphazane species, [(μ-NH){PE(μ-N^tBu)₂PE(NH^tBu)}₂] (E = O and S), bis-P^V₂N₂, displaying bimodal bifurcated R²₁(8) and trifurcated R³₁(8,8) hydrogen bonding motifs. The reported species reversibly switch their topological arrangement in the presence and absence of anions. Our results underscore these species as versatile building blocks for molecular machines and switches, as well as supramolecular chemistry and crystal engineering based on cyclophosphazane frameworks.

中文翻译：

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具有旋转分叉到三分叉氢键作用模式的主族分子开关

自 Jean-Pierre Sauvage、Fraser Stoddart 和 Ben Feringa 获得 2016 年诺贝尔化学奖以来，人工分子机器引起了科学界的全面关注。分子机械（轮烷、转子和开关）过去和现在的发展主要依赖有机化合物作为分子结构单元，用于组装和未来发展。相比之下，主族化学空间传统上并不是分子机器领域的一部分。p 嵌段内的氧化态和化合价范围提供了大量具有各种化学性质的结构。这种化学多样性——当在分子机器中实施时——可能成为该领域的变革力量。在此背景下，^t Bu) ₂ PE(NH ^t Bu)} ₂ ] (E = O and S)，bis-P ^V ₂ N ₂，显示双峰分叉 R ² ₁ (8) 和三分叉 R ³ ₁ (8,8) 氢键图案。报告的物种在存在和不存在阴离子的情况下可逆地改变它们的拓扑排列。我们的结果强调了这些物种是分子机器和开关的通用构建块，以及基于环磷氮烷框架的超分子化学和晶体工程。