Quantum cluster equilibrium theory treatment of hydrogen-bonded liquids: water, methanol and ethanol

Borowski, Piotr; Jaroniec, Justyna; Janowski, Tomasz; Woliński, Krzysztof

doi:10.1080/0026897031000085083

Cited by 36 publications

(40 citation statements)

References 18 publications

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“…at least once in order to capture the fundamental physics of the system. Since pure water has already been extensively studied using the QCE method, [56][57][58][59][60][61][62][63][64][65][66][67][68] we chose a set of clusters that was found to be important in those earlier studies. It consists of the monomer (w1), the dimer (w2), two ring structures (w5, w6), a cube (w8) and a bicyclic cluster (w9), which we call spiro cluster because of its similarity to organic spiro compounds.…”

Section: Choice Of the Cluster Setmentioning

confidence: 99%

Quantum cluster equilibrium model of N-methylformamide–water binary mixtures

Domaros

Jähnigen

Friedrich

et al. 2016

The Journal of Chemical Physics

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The established quantum cluster equilibrium (QCE) approach is refined and applied to Nmethylformamide (NMF) and its aqueous solution. The QCE method is split into two iterative cycles: one which converges to the liquid phase solution of the QCE equations and another which yields the gas phase. By comparing Gibbs energies, the thermodynamically stable phase at a given temperature and pressure is then chosen. The new methodology avoids metastable solutions and allows a different treatment of the mean-field interactions within the gas and liquid phases. These changes are of crucial importance for the treatment of binary mixtures. For the first time in a QCE study, the cis-trans-isomerism of a species (NMF) is explicitly considered. Cluster geometries and frequencies are calculated using density functional theory (DFT) and complementary coupled cluster single point energies are used to benchmark the DFT results. Independent of the selected quantum-chemical method, a large set of clusters is required for an accurate thermodynamic description of the binary mixture. The liquid phase of neat NMF is found to be dominated by the cyclic trans-NMF pentamer, which can be interpreted as a linear trimer that is stabilized by explicit solvation of two further NMF molecules. This cluster reflects the known hydrogen bond network preferences of neat NMF. C 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license

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Section: Choice Of the Cluster Setmentioning

confidence: 99%

Quantum cluster equilibrium model of N-methylformamide–water binary mixtures

Domaros

Jähnigen

Friedrich

et al. 2016

The Journal of Chemical Physics

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“…Bulk alcohols are composed of hydrogen-bonded clusters [25,26] that remain in thermodynamic equilibrium. According to Borowski et al [25], bulk methanol is mostly composed of hepta-, hexa-, penta-, tetra-and trimeric cluster structures. Monomeric methanol molecules constitute only a minor fraction of bulk alcohol.…”

Section: -The Abtsmentioning

confidence: 99%

The importance of solvent type in estimating antioxidant properties of phenolic compounds by ABTS assay

Dawidowicz

Olszowy

2013

Eur Food Res Technol

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ABTS assay belongs to the most popular methods employed for estimating antioxidant activity. However, researchers seldom pay attention to specific factors influencing the determination of antioxidant activity of the examined compounds and mixtures. The paper shows that the type of alcohol used significantly influences the estimation of antioxidant activity of phenolic compounds in ABTS assay, namely that their antioxidant activity increase with the lengthening of the aliphatic chain in alcohol. It results rather from the changes in ABTS•1 solvatation energy by the employed alcohols than from dissociation variations of phenolic compounds. The obtained results point to the difficulties in the correct estimation of the real antioxidant properties of plant and food extracts by ABTS assay. The presented results have also an ecological implication as they refer to the difference in estimation of antioxidant properties of compounds resulting from the replacement of toxic methanol by GRAS (Generally-Recognized-As Safe) solvents, ethanol and propanol.

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“…Experimental values of water monomer in various solvents (taken from [37]) are shown by dashed area. Calculated monomer shift in vacuo is shown by open circle, pentamer and hexamer shifts are taken from [16]. More comments in text.…”

Section: Methods Of Calculationsmentioning

confidence: 99%

“…1). Therefore, these structures are considered as dominant ones in the liquid water [16]. In addition a tetrahedrallycoordinated pentamer (Structure V, Table 1) was studied in the present work in order to evaluate the chemical shift of water in the limiting aggregation case of n → ∞.…”

Section: Figmentioning

confidence: 99%

“…Because of fast molecular motion the NMR signal shifts in the liquids are determined by isotropic part of magnetic shielding tensors of corresponding nuclei. Most significant last period works on magnetic shielding properties of water are devoted either to pure quantum chemistry calculations or to some joint treatments applying molecular dynamics and chemical equilibrium theories [10][11][12][13][14][15][16][17][18][19]. Unfortunately most of them deal with water structures in vacuo, or presented data sets are not complete enough for the modelling of NMR spectra of mentioned systems.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic shielding properties of water in various molecular and molecular-ionic structures

Aidas¹

2006

Lithuanian J. Phys.

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H and17 O magnetic shielding tensors of water molecules in various water clusters, as well as in water-pyridine H-bond complexes and in molecular-ionic structure of Br − (H2O)6 have been calculated using density functional theory. The full geometry optimization was performed in the framework of Becke's three parameter hybrid method and the Lee-Yang-Parr correlation functional (B3LYP) combined with 6-311++G** basis set. Magnetic shielding tensors have been calculated using the hybrid functional of Perdew, Burke, and Ernzerhof (PBE1PBE) and the gauge-including atomic orbital (GIAO) approach was applied to ensure gauge invariance of the results. Solvent effects were taken into account by polarizable continuum model (PCM). The calculated NMR parameters are compared with the corresponding experimental data for aqueous system, which exhibit an unusual critical behaviour and phase transitions.

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Quantum cluster equilibrium theory treatment of hydrogen-bonded liquids: water, methanol and ethanol

Cited by 36 publications

References 18 publications

Quantum cluster equilibrium model of N-methylformamide–water binary mixtures

Quantum cluster equilibrium model of N-methylformamide–water binary mixtures

The importance of solvent type in estimating antioxidant properties of phenolic compounds by ABTS assay

Magnetic shielding properties of water in various molecular and molecular-ionic structures

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