Complexation of anionic and neutral species by sehydroacetic acid and calix[4]arene derivates in solution

Bregović, Nikola (2014) Complexation of anionic and neutral species by sehydroacetic acid and calix[4]arene derivates in solution. Doctoral thesis, Faculty of Science > Department of Chemistry.

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Abstract

Complexation of various species by amine, urea, and thiourea derivatives of dehidroacetic acid (3acetyl-2-hydroxy-6-methyl-4H-pyran-4-one, DHA), as well as by calix[4]arene derivative bearing tryptophan units at the lower rim, has been studied using NMR spectroscopy, potentiometric, spectrophotometric, microcalorimetric, and conductometric titrations. Complexation reactions of a series of inorganic anions (Cl–, NO3–, ClO4–) with amine derivatives of DHA were studied in methanol. In addition, complexation of several dicarboxylic acids (maleic, fumaric, phthalic, isophthalic, and succinic) by the symmetrical monoamine DHA derivative was investigated. The protonation properties of the acids and the aminebased DHA receptors were also studied. In the case of inorganic anions, no selectivity was observed. In contrast, it was found that the symmetrical monamine receptor was selective for maleic and phthalic acid among the investigated dicarboxylic acids. The thermodynamic parameters for complex formation of (thio)urea derivatives with several anions (H2PO4–, HSO4–, AcO– Cl–,) in acetonitrile and dimethyl sulfoxide were determined. The complexes were found to be of 1:1 (anion:receptor) stoichiometry, with the exception of dihydrogen phosphate anion, which formed both 1:1 and 2:1 complexes. It was found that the extent of the dimerisation of dihydrogen phosphate was significant in both solvents used. Hence, this reaction was also quantitatively studied, and was taken into account in the course of the anion-binding studies. Calix[4]arene derivative with tryptophan subunits was shown to be selective for fluoride anion among the other halide anions investigated (Cl–, Br–, I–).The possibility of ion-pair binding by this derivative was also explored, whereby the ion-association process, i.e. formation of M species (M stands for metal), was found to play an important role. The equilibrium constant for the formation of Na+F–, PF associate was determined potentiometrically. The gathered results were discussed with respect to anion and receptor structural properties. The solvent effect on the studied equilibria was also addressed in detail.

Item Type: Thesis (Doctoral thesis)
Keywords: anion receptors, dehydroacetic acid, calix[4]arene, complexes, stability constant, thermodynamics
Supervisor: Tomišić, Vladislav
Date: 2014
Number of Pages: 208
Subjects: NATURAL SCIENCES > Chemistry
Divisions: Faculty of Science > Department of Chemistry
Depositing User: mag. bibl. Ana Šafran
Date Deposited: 18 Dec 2014 16:09
Last Modified: 15 Jun 2015 12:38
URI: http://digre.pmf.unizg.hr/id/eprint/3556

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