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

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, alt...

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Main Authors: Marija Cvetnić, Tamara Rinkovec, Robert Vianello, Gordan Horvat, Nikola Bregović, Vladislav Tomišić
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Molecules
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Online Access:https://www.mdpi.com/1420-3049/30/11/2464
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author Marija Cvetnić
Tamara Rinkovec
Robert Vianello
Gordan Horvat
Nikola Bregović
Vladislav Tomišić
author_facet Marija Cvetnić
Tamara Rinkovec
Robert Vianello
Gordan Horvat
Nikola Bregović
Vladislav Tomišić
author_sort Marija Cvetnić
collection DOAJ
description 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<sub>4</sub>, and NaH<sub>2</sub>PO<sub>4</sub>) 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<sub>4</sub> 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.
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spelling doaj-art-bbcdc88f989547dc89e69eed8eed40e92025-08-20T03:11:19ZengMDPI AGMolecules1420-30492025-06-013011246410.3390/molecules30112464A Detailed Thermodynamic Description of Ion Pair Binding by a Calix[4]arene Derivative Containing Urea and Amide FunctionalitiesMarija Cvetnić0Tamara Rinkovec1Robert Vianello2Gordan Horvat3Nikola Bregović4Vladislav Tomišić5Division of Physical Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, CroatiaLaboratory for the Computational Design and Synthesis of Functional Materials, Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, CroatiaLaboratory for the Computational Design and Synthesis of Functional Materials, Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, CroatiaDivision of Physical Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, CroatiaDivision of Physical Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, CroatiaDivision of Physical Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, CroatiaReceptors 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<sub>4</sub>, and NaH<sub>2</sub>PO<sub>4</sub>) 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<sub>4</sub> 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.https://www.mdpi.com/1420-3049/30/11/2464ion paircalix[4]arenecooperativitybinding thermodynamicsmolecular dynamicssolution equilibria
spellingShingle Marija Cvetnić
Tamara Rinkovec
Robert Vianello
Gordan Horvat
Nikola Bregović
Vladislav Tomišić
A Detailed Thermodynamic Description of Ion Pair Binding by a Calix[4]arene Derivative Containing Urea and Amide Functionalities
Molecules
ion pair
calix[4]arene
cooperativity
binding thermodynamics
molecular dynamics
solution equilibria
title A Detailed Thermodynamic Description of Ion Pair Binding by a Calix[4]arene Derivative Containing Urea and Amide Functionalities
title_full A Detailed Thermodynamic Description of Ion Pair Binding by a Calix[4]arene Derivative Containing Urea and Amide Functionalities
title_fullStr A Detailed Thermodynamic Description of Ion Pair Binding by a Calix[4]arene Derivative Containing Urea and Amide Functionalities
title_full_unstemmed A Detailed Thermodynamic Description of Ion Pair Binding by a Calix[4]arene Derivative Containing Urea and Amide Functionalities
title_short A Detailed Thermodynamic Description of Ion Pair Binding by a Calix[4]arene Derivative Containing Urea and Amide Functionalities
title_sort detailed thermodynamic description of ion pair binding by a calix 4 arene derivative containing urea and amide functionalities
topic ion pair
calix[4]arene
cooperativity
binding thermodynamics
molecular dynamics
solution equilibria
url https://www.mdpi.com/1420-3049/30/11/2464
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