In: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2020, vol. 237, p. 118416
The paper presents the synthesis and characterization of two 4-substituted phthalimide 2-hydroxy-Schiff bases containing salicylic (4) and 2-hydroxy-1-naphthyl (5) moieties. The structural differences of 2-hydroxyaryl substituents, resulting in different enol/keto tautomeric behaviour, depending on the solvent environment were studied by absorption UV–Vis spectroscopy. Compound 5 is...
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In: Molecules, 2020, vol. 25, no. 2, p. 298
Two novel pinene-type ligands have been synthesized and their tautomeric and self- associating behavior studied in solution and in the solid state. The first ligand, an acetylated derivative of 5,6-pinene-bipyridine, displays keto-enol tautomerism in solution. This tautomeric equilibrium was studied by NMR and UV-Vis spectroscopy in various solvents, and the results were compared with the ones...
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In: Beilstein Journal of Organic Chemistry, 2019, vol. 15, no. 1, p. 1898–1906
The concept for sensing systems using the tautomerism as elementary signaling process has been further developed by synthesizing a ligand containing 4- (phenyldiazenyl)naphthalene-1-ol as a tautomeric block and an amide group as metal capturing antenna. Although it has been expected that the intramolecular hydrogen bonding (between the tautomeric hydroxy group and the nitrogen atom from the...
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In: Journal of Molecular Liquids, 2019, vol. 283, p. 242–248
The title compound potentially can exist as four isomers in solution. Recently Lycka has proposed a protocol for distinguishing two of them based on 15N NMR. This approach has been confirmed theoretically, in the current study, and further developed into a logical scheme that allows the existence of each of the isomers to be proven in solution. The experimental data, obtained by NMR and...
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In: Dyes and Pigments, 2019, vol. 165, p. 157–163
In order to meet the need for NMR reference compounds in the study of tautomeric azo dyes, two series of azo dyes, derived from 3-methyl-1-phenyl-4- (phenyldiazenyl)-1H-pyrazol-5-amine and 5-methyl-2-phenyl-4-(2- phenylhydrazono)-2,4-dihydro-3H-pyrazol-3-one, have been studied by using molecular spectroscopy (UV–Vis and NMR) and quantum-chemical calculations (M06- 2X/TZVP) in solution. The...
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In: ChemistrySelect, 2018, vol. 3, no. 43, p. 12017–12021
A series of Betti bases from 4‐(3‐pyridyl)azo‐1‐naphthol dye, possessing flexible methylene or more constrained aryl‐methyne spaced NH‐containing side‐chains, were obtained and characterized. It was shown by NMR spectroscopy that the ligands exist in keto form. The products’ structure was confirmed by single crystal XRD of a selected sample. A study on the coordination ability...
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In: Dyes and Pigments, 2018, vol. 156, p. 91-99
A series of aryl azo derivatives of naphthols (1–3) were studied by means of UV–Vis and NMR spectroscopy in different solvents as well as by quantum chemical calculations and X-ray analysis. Previous studies have shown that Sudan I (1) exists as a tautomeric mixture. The effect of the solvents is minimized by the existing intramolecular hydrogen bond. Therefore, the influence on the...
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In: Surveys in Geophysics, 2012, vol. 33, no. 1, p. 169-209
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In: The European Physical Journal A, 2013, vol. 49, no. 12, p. 1-18
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In: Zeitschrift für Gerontologie und Geriatrie, 2010, vol. 43, no. 1, p. 36-41
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