Cvetnić Marija, Rinkovec Tamara, Vianello Robert, Horvat Gordan, Bregović Nikola, Tomišić Vladislav
Division of Physical Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia.
Laboratory for the Computational Design and Synthesis of Functional Materials, Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia.
Molecules. 2025 Jun 4;30(11):2464. doi: 10.3390/molecules30112464.
Receptors capable of binding both positive and negative ions are an important domain of supramolecular chemistry with valuable application potential. A Complete thermodynamic description of the equilibria related to ion pair recognition is beneficial in developing the optimized receptor systems, although it represents a difficult task that is rarely resolved due to various coupled processes. Here, we present a comprehensive study of ion pair (NaCl, NaHSO, and NaHPO) binding by a ureido-amide calix[4]arene host in acetonitrile using a series of experimental techniques and molecular dynamics simulations. We devoted particular attention to characterizing the side processes (ion association and salt precipitation) and included them in the models describing ion pair complex formation. For this purpose, a multimethod approach (potentiometry, conductometry, ITC, flame AES) was employed, generating reliable data which provided insight into the thermodynamic effect of each included equilibrium. Positive cooperativity was observed in the context of NaCl and NaHSO binding by the studied calixarene. Computational results related to the NaCl complex in acetonitrile revealed that favorable Coulombic interactions, changes in affinity for solvent molecule inclusion, and intramolecular hydrogen bonding contributed to cation-induced cooperativity.
能够结合正负离子的受体是超分子化学的一个重要领域，具有宝贵的应用潜力。尽管由于各种耦合过程，对与离子对识别相关的平衡进行完整的热力学描述是一项艰巨的任务，很少能得到解决，但这对于开发优化的受体系统是有益的。在这里，我们使用一系列实验技术和分子动力学模拟，对乙腈中脲基酰胺杯[4]芳烃主体与离子对（NaCl、NaHSO₄和NaH₂PO₄）的结合进行了全面研究。我们特别关注表征副反应（离子缔合和盐沉淀），并将它们纳入描述离子对络合物形成的模型中。为此，采用了多方法途径（电位滴定法、电导法、等温滴定量热法、火焰原子发射光谱法），生成了可靠的数据，这些数据提供了对每个包含的平衡的热力学效应的深入了解。在所研究的杯芳烃与NaCl和NaHSO₄结合的情况下观察到了正协同效应。与乙腈中NaCl络合物相关的计算结果表明，有利的库仑相互作用、对溶剂分子包合亲和力的变化以及分子内氢键有助于阳离子诱导的协同作用。
