A Detailed Thermodynamic Description of Ion Pair Binding by a Calix[4]arene Derivative Containing Urea and Amide Functionalities

Cvetnić, Marija; Rinkovec, Tamara; Vianello, Robert; Horvat, Gordan; Bregović, Nikola; Tomišić, Vladislav (2025) A Detailed Thermodynamic Description of Ion Pair Binding by a Calix[4]arene Derivative Containing Urea and Amide Functionalities. Molecules, 30 (11). ISSN 1420-3049

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Abstract

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, NaHSO4, and NaH2PO4) 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 NaHSO4 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.

Item Type:	Article
Uncontrolled Keywords:	ion pair; calix[4]arene; cooperativity; binding thermodynamics; molecular dynamics; solution equilibria; acetonitrile; solubility
Subjects:	NATURAL SCIENCES > Chemistry
Divisions:	Division of Organic Chemistry and Biochemistry
Projects:	Project title Project leader Project code Project type Termodinamički, spektroskopski i strukturni aspekti koordinacijskih reakcija kaliksarena UNSPECIFIED UNSPECIFIED UNSPECIFIED Koordinacijske reakcije makrocikličkih liganada u otopini-MacroSol Vladislav Tomišić IP-2019-04-9560 HRZZ
Depositing User:	Lorena Palameta
Date Deposited:	29 Jul 2025 06:52
URI:	http://fulir.irb.hr/id/eprint/9916
DOI:	10.3390/molecules30112464

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