The current work showcases general principles at play in systems consisting of cations present inside molecular cages. Such systems, relevant to chemistry and biology, have been carefully investigated by computational methods. The important Ge(II)-encapsulating cage systems have been studied first. The very fact that such compounds exist appears highly unlikely, given the highly reactive nature of the Ge(II) dication. Our studies reveal what really occurs in solution when such complexes are formed: the Ge(II) dications are actually present as [Ge–X]⁺ (where X is the “non-coordinating” counterion employed in such systems) during entry and subsequent existence at the center of the cage. Hence, what is actually present is a “pseudomonocation”. Interestingly, such pseudomonocation-encapsulated cages are seen to be equally relevant in systems of biological importance, such as for dicationic s block-based ionophores. In explaining such cases, the concept of “isoionicity” is introduced, demonstrating that the counterion-coordinated dications are isoionic with a monocation, such as Li(I), isolated in the same ionophore.

中文翻译：

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揭示抗衡阴离子在“笼中的阳离子”系统中的隐藏作用。

当前的工作展示了由分子笼中存在的阳离子组成的系统中起作用的一般原理。已经通过计算方法仔细研究了与化学和生物学有关的此类系统。首先研究了重要的Ge（II）封装笼系统。考虑到Ge（II）指示剂具有高度反应性，这种化合物存在的事实看来极不可能。我们的研究揭示了当形成这种络合物时溶液中真正发生的情况：Ge（II）指示实际上以[Ge–X] ^{+的形式存在}（其中X是此类系统中使用的“非配位”抗衡离子）在进入并随后存在于笼子中心的过程中。因此，实际存在的是“伪单阳离子”。有趣的是，这种伪单阳离子包封的笼子在具有生物学重要性的系统中，例如对于基于药物的基于嵌段的离子载体，具有同等重要的意义。在解释此类情况时，引入了“等离子性”的概念，表明抗衡离子配位的离子是在同一离子载体中分离的带有单阳离子（例如Li（I））的等离子离子。