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Leko K, Usenik A, Cindro N, Modrušan M, Požar J, Horvat G, Stilinović V, Hrenar T, Tomišić V. Enhancing the Cation-Binding Ability of Fluorescent Calixarene Derivatives: Structural, Thermodynamic, and Computational Studies. ACS Omega 2023; 8:43074-43087. [PMID: 38024729 PMCID: PMC10652827 DOI: 10.1021/acsomega.3c06509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/05/2023] [Accepted: 10/11/2023] [Indexed: 12/01/2023]
Abstract
Novel fluorescent calix[4]arene derivatives L1 and L2 were synthesized by introducing phenanthridine moieties at the lower calixarene rim, whereby phenanthridine groups served as fluorescent probes and for cation coordination. To enhance the cation-binding ability of the ligands, besides phenanthridines, tertiary-amide or ester functionalities were also introduced in the cation-binding site. Complexation of the prepared compounds with alkali metal cations in acetonitrile (MeCN), methanol (MeOH), ethanol (EtOH), N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO) was investigated at 25 °C experimentally (UV spectrophotometry, fluorimetry, microcalorimetry, and in the solid state by X-ray crystallography) and by means of computational techniques (classical molecular dynamics and DFT calculations). The thermodynamic parameters (equilibrium constants and derived standard reaction Gibbs energies, reaction enthalpies, and entropies) of the corresponding reactions were determined. The tertiary-amide-based compound L1 was found to have a much higher affinity toward cations compared to ester derivative L2, whereby the stabilities of the ML1+ and ML2+ complexes were quite solvent-dependent. The stability decreased in the solvent order: MeCN ≫ EtOH > MeOH > DMF > DMSO, which could be explained by taking into account the differences in the solvation of the ligands as well as free and complexed alkali metal cations in the solvents used. The obtained thermodynamic quantities were thoroughly discussed regarding the structural characteristics of the studied compounds, as well as the solvation abilities of the solvents examined. Molecular and crystal structures of acetonitrile and water solvates of L1 and its sodium complex were determined by single-crystal X-ray diffraction. The results of computational studies provided additional insight into the L1 and L2 complexation properties and structures of the ligands and their cation complexes.
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Affiliation(s)
| | | | - Nikola Cindro
- Department of Chemistry,
Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia
| | - Matija Modrušan
- Department of Chemistry,
Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia
| | - Josip Požar
- Department of Chemistry,
Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia
| | - Gordan Horvat
- Department of Chemistry,
Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia
| | - Vladimir Stilinović
- Department of Chemistry,
Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia
| | - Tomica Hrenar
- Department of Chemistry,
Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia
| | - Vladislav Tomišić
- Department of Chemistry,
Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia
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Petters I, Modrušan M, Vidović N, Crnolatac I, Cindro N, Piantanida I, Speranza G, Horvat G, Tomišić V. Anion-Sensing Properties of Cyclopentaphenylalanine. Molecules 2022; 27:molecules27123918. [PMID: 35745042 PMCID: PMC9228215 DOI: 10.3390/molecules27123918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/15/2022] [Accepted: 06/16/2022] [Indexed: 11/16/2022]
Abstract
Cyclic pentaphenylalanine was studied as an efficient anion sensor for halides, thiocyanate and oxoanions in acetonitrile and methanol. Stability constants of the corresponding complexes were determined by means of fluorimetric, spectrophotometric, 1H NMR, and microcalorimetric titrations. A detailed structural overview of receptor–anion complexes was obtained by classical molecular dynamics (MD) simulations. The results of 1H NMR and MD studies indicated that the bound anions were coordinated by the amide groups of cyclopeptide, as expected. Circular dichroism (CD) titrations were also carried out in acetonitrile. To the best of our knowledge, this is the first example of the detection of anion binding by cyclopeptide using CD spectroscopy. The CD spectra were calculated from the structures obtained by MD simulations and were qualitatively in agreement with the experimental data. The stoichiometry of almost all complexes was 1:1 (receptor:anion), except for dihydrogen phosphate where the binding of dihydrogen phosphate dimer was observed in acetonitrile. The affinity of the cyclopeptide receptor was correlated with the structure of anion coordination sphere, as well as with the solvation properties of the examined solvents.
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Affiliation(s)
- Ivan Petters
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia; (I.P.); (M.M.); (N.C.)
| | - Matija Modrušan
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia; (I.P.); (M.M.); (N.C.)
| | - Nikolina Vidović
- Dipartimento di Chimica, Università degli Studi di Milano, Via C. Golgi, 19, 20133 Milan, Italy; (N.V.); (G.S.)
- Institute of Agriculture and Tourism, Department of Agriculture and Nutrition, Karla Huguesa 8, 52440 Poreč, Croatia
| | - Ivo Crnolatac
- Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; (I.C.); (I.P.)
| | - Nikola Cindro
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia; (I.P.); (M.M.); (N.C.)
| | - Ivo Piantanida
- Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; (I.C.); (I.P.)
| | - Giovanna Speranza
- Dipartimento di Chimica, Università degli Studi di Milano, Via C. Golgi, 19, 20133 Milan, Italy; (N.V.); (G.S.)
| | - Gordan Horvat
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia; (I.P.); (M.M.); (N.C.)
- Correspondence: (G.H.); (V.T.)
| | - Vladislav Tomišić
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia; (I.P.); (M.M.); (N.C.)
- Correspondence: (G.H.); (V.T.)
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Požar J, Cvetnić M, Usenik A, Cindro N, Horvat G, Leko K, Modrušan M, Tomišić V. The Role of Triazole and Glucose Moieties in Alkali Metal Cation Complexation by Lower-Rim Tertiary-Amide Calix[4]arene Derivatives. Molecules 2022; 27:molecules27020470. [PMID: 35056784 PMCID: PMC8780480 DOI: 10.3390/molecules27020470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/05/2022] [Accepted: 01/06/2022] [Indexed: 11/16/2022]
Abstract
The binding of alkali metal cations with two tertiary-amide lower-rim calix[4]arenes was studied in methanol, N,N-dimethylformamide, and acetonitrile in order to explore the role of triazole and glucose functionalities in the coordination reactions. The standard thermodynamic complexation parameters were determined microcalorimetrically and spectrophotometrically. On the basis of receptor dissolution enthalpies and the literature data, the enthalpies for transfer of reactants and products between the solvents were calculated. The solvent inclusion within a calixarene hydrophobic basket was explored by means of 1H NMR spectroscopy. Classical molecular dynamics of the calixarene ligands and their complexes were carried out as well. The affinity of receptors for cations in methanol and N,N-dimethylformamide was quite similar, irrespective of whether they contained glucose subunits or not. This indicated that sugar moieties did not participate or influence the cation binding. All studied reactions were enthalpically controlled. The peak affinity of receptors for sodium cation was noticed in all complexation media. The complex stabilities were the highest in acetonitrile, followed by methanol and N,N-dimethylformamide. The solubilities of receptors were greatly affected by the presence of sugar subunits. The medium effect on the affinities of calixarene derivatives towards cations was thoroughly discussed regarding the structural properties and solvation abilities of the investigated solvents.
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Affiliation(s)
- Josip Požar
- Correspondence: (J.P.); (V.T.); Tel.: +385-1-46-06-133 (J.P.); +385-1-46-06-136 (V.T.)
| | | | | | | | | | | | | | - Vladislav Tomišić
- Correspondence: (J.P.); (V.T.); Tel.: +385-1-46-06-133 (J.P.); +385-1-46-06-136 (V.T.)
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