Tautomerism in Azo and Azomethyne Dyes: When and If Theory Meets Experiment

Antonov, L.

doi:10.3390/molecules24122252

Cited by 37 publications

(26 citation statements)

References 73 publications

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“…This fitted hybrid meta-GGA functional with 54% HF exchange is specially developed to describe main-group thermochemistry and non-covalent interactions, showing very good results in prediction of the position of tautomeric equilibria [ 27 – 29 , 52 – 54 ]. In addition, TautLYP [ 55 ], a specially optimized to predict the tautomerism in azodyes and Schiff bases, B3LYP-based functional, was used with 6–31 ++Gdp basis set. All structures were optimized in ground state without restrictions, using tight optimization criteria and ultrafine grid in the computation of two-electron integrals and their derivatives.…”

Section: Methodsmentioning

confidence: 99%

Favipiravir tautomerism: a theoretical insight

Antonov

2020

Theor Chem Acc

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There is no experimental information about the tautomerism of Favipiravir (T-705). Therefore, its tautomeric state was predicted by using density functional theory in gas phase and in solution (toluene, acetonitrile and water). The results have shown that, in neutral state, the enol form is strongly dominating in both gas phase and solution. The carboxamide group is easily protonated in the presence of acid, which leads to shift of the tautomeric equilibrium toward the keto tautomer. In order to validate the theoretical predictions, 2-hydroxy pyridine and 2-hydroxy pyrazine were also included in the set of studied compounds. The available experimental data about their tautomerism are in very good agreement with the theoretical predictions, which validate the conclusions made for T-705.

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Section: Methodsmentioning

confidence: 99%

Favipiravir tautomerism: a theoretical insight

Antonov

2020

Theor Chem Acc

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“…However, the tautomeric equilibrium has not been switched fully to either of the tautomers in solution. For instance, the experimentally determined Δ G values at room temperature range from 1.42 kcal/mol, which corresponds to around 8% (in cyclohexane) or 10% (in methylcyclohexane/toluene) of the K tautomer [11–12], to −0.71 kcal/mol in chloroform [8], where this tautomer dominates. The Δ G value of 0.33 kcal/mol in acetonitrile, determined experimentally [8], have been used to validate the level of theory used in the current study.…”

Section: Resultsmentioning

confidence: 99%

Tautomerism as primary signaling mechanism in metal sensing: the case of amide group

Deneva

Dobrikov

Crochet

et al. 2019

Beilstein J. Org. Chem.

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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 amide group) could stabilize the pure enol form in some solvents, the keto tautomer is also observed. This is a result from the formation of intramolecular associates in some solvents. Strong bathochromic and hyperchromic effects in the visible spectra accompany the 1:1 formation of complexes with some alkaline earth metal ions.

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“…Previous studies indicated that the PBE functional, one of the most popular generalized-gradient approximation (GGA) functionals, offers a reasonable description of the frequencies and intensities of Raman active vibrations of the PQ molecule [35]. Thanks to the low computational cost of PBE, as compared to meta-GGA or hybrid functionals [36], we were able to calculate not only the frequencies of Γ-point vibrational modes but also their Raman activity, as well as the phonon dispersion. We note that van der Waals interactions, poorly modelled with GGA functionals, were accounted for with Upon compression of powdered PQ, the colour of the sample changes from off-white at 1 atm to light orange (see Figure S1 in the Supplementary Materials) indicating a reduction of the band gap.…”

Section: High-pressure Behaviour Of Pqmentioning

confidence: 99%

Hydrogen-Bonded Cyclic Dimers at Large Compression: The Case of 1H-pyrrolo[3,2-h]quinoline and 2-(2′-pyridyl)pyrrole

et al. 2021

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1H-pyrrolo[3,2-h]qinoline (PQ) and 2-(2′-pyridyl)pyrrole (PP) are important systems in the study of proton-transfer reactions. These molecules possess hydrogen bond donor (pyrrole) and acceptor (pyridine) groups, which leads to the formation of cyclic dimers in their crystals. Herein, we present a joint experimental (Raman scattering) and computational (DFT modelling) study on the high-pressure behaviour of PQ and PP molecular crystals. Our results indicate that compression up to 10 GPa (100 kbar) leads to considerable strengthening of the intermolecular hydrogen bond within the cyclic dimers. However, the intramolecular N–H∙∙∙N interaction is either weakly affected by pressure, as witnessed in PQ, or weakened due to compression-induced distortions of the molecule, as was found for PP. Therefore, we propose that the compression of these systems should facilitate double proton transfer within the cyclic dimers of PQ and PP, while intramolecular transfer should either remain unaffected (for PQ) or weakened (for PP).

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Tautomerism in Azo and Azomethyne Dyes: When and If Theory Meets Experiment

Cited by 37 publications

References 73 publications

Favipiravir tautomerism: a theoretical insight

Favipiravir tautomerism: a theoretical insight

Tautomerism as primary signaling mechanism in metal sensing: the case of amide group

Hydrogen-Bonded Cyclic Dimers at Large Compression: The Case of 1H-pyrrolo[3,2-h]quinoline and 2-(2′-pyridyl)pyrrole

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