A DFT study on the effect of Au-decoration on the interaction of adrucil drug with BC2N nanotubes in the gas phase and aqueous solution

The tautomerization of glycine via a triple proton transfer was investigated both in the gas phase and in aqueous solution using the B3LYP/6-31+G(d,p) level of theory. Fully optimized complexes of the neutral and zwitterion forms of glycine with 1,3-propanediol were used for the reactant and product forms, respectively. The hydroxyl groups in the diol are conveniently oriented for glycine tautomerization through a concerted triple proton transfer facilitated by a network of three hydrogen bonds: N-H…O-H…O-H…O=C. The activation energy for the zwitterion à neutral process increases in solution. Also, the diol-glycine complex favors the neutral over the zwitterion form in a vacuum, but the opposite is true in solution. For comparative purposes, the tautomerization of glycine via a three-proton transfer mediated by two molecules of water was also examined. The results are qualitatively similar, albeit with activation energies that are smaller to those found in the corresponding diol-mediated tautomerization. KEYWORDS: Glycine; zwitterion, diol-mediated tautomerization; water-mediated tautomerization

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DFT study of structural and electronic properties of gallic acid and its anions in gas phase and in aqueous solution

Structural Chemistry ◽

10.1007/s11224-017-0958-3 ◽

2017 ◽

Vol 28 (6) ◽

pp. 1789-1802 ◽

Cited By ~ 10

Author(s):

Bharti Badhani ◽

Rita Kakkar

Keyword(s):

Aqueous Solution ◽

Electronic Properties ◽

Gallic Acid ◽

Gas Phase ◽

Dft Study ◽

Structural And Electronic Properties

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2-Deoxyribose Radicals in the Gas Phase and Aqueous Solution. Transient Intermediates of Hydrogen Atom Abstraction from 2-Deoxyribofuranose

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20051769 ◽

2005 ◽

Vol 70 (11) ◽

pp. 1769-1786 ◽

Cited By ~ 4

Author(s):

Luc A. Vannier ◽

Chunxiang Yao ◽

František Tureček

Keyword(s):

Aqueous Solution ◽

Hydrogen Atom ◽

Gas Phase ◽

Computational Study ◽

Hydrogen Atom Abstraction ◽

Oh Radical ◽

Free Energies ◽

Intramolecular Hydrogen ◽

Solvation Free Energies ◽

Transient Intermediates

A computational study at correlated levels of theory is reported to address the structures and energetics of transient radicals produced by hydrogen atom abstraction from C-1, C-2, C-3, C-4, C-5, O-1, O-3, and O-5 positions in 2-deoxyribofuranose in the gas phase and in aqueous solution. In general, the carbon-centered radicals are found to be thermodynamically and kinetically more stable than the oxygen-centered ones. The most stable gas-phase radical, 2-deoxyribofuranos-5-yl (5), is produced by H-atom abstraction from C-5 and stabilized by an intramolecular hydrogen bond between the O-5 hydroxy group and O-1. The order of radical stabilities is altered in aqueous solution due to different solvation free energies. These prefer conformers that lack intramolecular hydrogen bonds and expose O-H bonds to the solvent. Carbon-centered deoxyribose radicals can undergo competitive dissociations by loss of H atoms, OH radical, or by ring cleavages that all require threshold dissociation or transition state energies >100 kJ mol-1. This points to largely non-specific dissociations of 2-deoxyribose radicals when produced by exothermic hydrogen atom abstraction from the saccharide molecule. Oxygen-centered 2-deoxyribose radicals show only marginal thermodynamic and kinetic stability and are expected to readily fragment upon formation.

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Simulation of UV Absorption Spectra and Relaxation Dynamics of Uracil and Uracil-Water Clusters

Physical Chemistry Chemical Physics ◽

10.1039/d0cp05618a ◽

2020 ◽

Author(s):

Branislav Milovanović ◽

Jurica Novak ◽

Mihajlo Etinski ◽

Wolfgang Domcke ◽

Nadja Doslic

Keyword(s):

Aqueous Solution ◽

Gas Phase ◽

Absorption Spectra ◽

Absorption Spectroscopy ◽

Water Clusters ◽

Uv Absorption ◽

Relaxation Dynamics ◽

Nonradiative Relaxation ◽

Uv Absorption Spectra ◽

Uv Absorption Spectroscopy

Despite many studies, the mechanisms of nonradiative relaxation of uracil in the gas phase and in aqueous solution are still not fully resolved. Here we combine theoretical UV absorption spectroscopy...

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