Calix[4]arenes have the ability to encapsulate biomimetic guests, offering interesting opportunities to explore their molecular recognition, very close to biological scenarios. In this study, p‐sulfonatocalix[4]arene (C4 A ) anions and hydrated alkali cations have been used for the in situ recognition of cationic 1,ω‐diammonium‐alkanes and 1,ω‐amino‐acids of variable lengths. NMR spectroscopy illustrates that these systems are stable in aqueous solution and the interaction process involves several binding states or stabilized conformations within the C4 A anion, depending of the nature of the guest. DOSY experiments showed that monomeric 1 : 1 host–guest species are present, while the cation does not influence their self‐assembly in solution. The folded conformations observed in the solid‐state X‐ray single‐crystal structures shed light on the constitutional adaptivity of flexible chains to environmental factors. Futhermore, a comprehensive screening of 30 single crystal structures helped to understand the in situ conformational fixation and accurate determination of the folded structures of the confined guest molecules, with a compression up to 40 % compared with their linear conformations.

中文翻译：

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对-Sulfonatocalix [4]芳烃宿主中烷基胺和氨基酸的渐进折叠和自适应多价识别：固态和溶液研究。

Calix [4]芳烃具有封装仿生客体的能力，为探索其分子识别提供了有趣的机会，非常接近生物学场景。在这项研究中，对-磺砜杯[4]芳烃（C4A）阴离子和水合碱性阳离子已用于原位识别长度可变的阳离子1，ω-二铵-烷烃和1，ω-氨基酸。NMR光谱表明，这些系统在水溶液中稳定，并且相互作用过程涉及C4 A内的几种结合状态或稳定的构象阴离子，取决于客人的性质。DOSY实验表明存在单体1：1的客体物种，而阳离子却不影响它们在溶液中的自组装。在固态X射线单晶结构中观察到的折叠构象揭示了柔性链对环境因素的结构适应性。此外，对30种单晶结构的全面筛选有助于了解原位构象固定，并精确确定了受限客体分子的折叠结构，与线性构象相比，压缩率高达40％。