The precise and effective separation of similar mixtures is one of the fundamental issues and essential tasks in chemical research. In the field of gas/vapor separation, the size difference among the molecular pairs/isomers of light hydrocarbons and aromatic compounds is generally 0.3–0.5 Å, and the boiling-point difference is generally 6–15 K. These are necessary industrial raw materials and have great separation demands. Still, their separation mainly relies on energy-intensive distillation technology. On the other hand, remarkably similar substances such as oxygen/argon and isotopologues usually exhibit size differences of only 0–0.07 Å and boiling-point differences of only 1–3 K. Although their industrial separation can be realized, their efficiency is considerably low. Therefore, effectively separating remarkably similar mixtures is crucial in fundamental chemistry and industry, but it remains a significant challenge. Porous coordination polymers (PCPs) or metal–organic frameworks (MOFs) are emerging materials platforms for designing adsorbents for separating similar mixtures. However, the reported PCPs did not work well for separating remarkably similar substances. The framework structures of the mainstream PCPs remain unchanged (rigid) or significantly change (globally flexible) upon adsorption. However, rigid and globally flexible PCPs find controlling the pore aperture in subangstrom precision challenging, a prerequisite for distinguishing remarkably similar substances. Thus, novel mechanisms and materials design principles are urgently needed to realize PCPs-based adsorptive separation of remarkably similar mixtures.

中文翻译：

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通过软多孔晶体中的局部动力学运动控制客体扩散，以分离水同位素和类似气体


精确有效地分离相似混合物是化学研究中的基本问题和基本任务之一。在气体/蒸汽分离领域，轻烃和芳香族化合物的分子对/异构体之间的尺寸差异一般为 0.3-0.5 Å，沸点差一般为 6-15 K。这些是必要的工业原料，具有很大的分离需求。尽管如此，它们的分离主要依赖于能源密集型蒸馏技术。另一方面，非常相似的物质（如氧/氩和同位素体）通常表现出仅 0-0.07 Å 的大小差异和仅 1-3 K 的沸点差异。虽然可以实现工业分离，但效率相当低。因此，在基础化学和工业中，有效分离非常相似的混合物至关重要，但这仍然是一个重大挑战。多孔配位聚合物 （PCP） 或金属有机框架 （MOF） 是设计用于分离类似混合物的吸附剂的新兴材料平台。然而，报道的 PCP 不能很好地分离非常相似的物质。主流 PCP 的框架结构在吸附时保持不变 （刚性） 或显着变化 （全局柔性）。然而，刚性和全局柔性 PCP 发现以亚埃精度控制孔径具有挑战性，这是区分非常相似物质的先决条件。因此，迫切需要新的机制和材料设计原理来实现基于 PCPs 的吸附分离非常相似的混合物。