Structural changes of the molecular complexes of pyridines with water and demixing phenomena in aqueous solutions

Brovchenko, Ivan; Oleinikova, Alla

doi:10.1063/1.473776

Cited by 40 publications

(41 citation statements)

References 46 publications

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“…The stability of protein structures over a limited temperature range, denaturing above and below this range, can also be evoked here. 14 well the slowing down of the dynamics and an increase of the correlation lengths in one of these systems ͑3-methylpyridine/water͒, 16 were recently reported. [9][10][11][12] This is analogous to the well known example of Li 2 SO 4 in water, where the solubility of the salt decreases between 0°C and 100°C from 36 to 31 g/l.…”

Section: Communicationsmentioning

confidence: 54%

Freezing on heating of liquid solutions

Plazanet

Floare

Johnson

et al. 2004

The Journal of Chemical Physics

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We report a reversible liquid-solid transition upon heating of a simple solution composed of a-cyclodextrine (alpha CD), water, and 4-methylpyridine. These solutions are homogeneous and transparent at ambient temperature and solidify when heated to temperatures between 45 degrees and 75 degrees. Quasielastic and elastic neutron scattering show that molecular motions are slowed down in the solid and that crystalline order is established. The solution "freezes on heating." This process is fully reversible, on cooling the solid melts. A rearrangement of hydrogen bonds is postulated to be responsible for the observed phenomenon.

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Section: Communicationsmentioning

confidence: 54%

Freezing on heating of liquid solutions

Plazanet

Floare

Johnson

et al. 2004

The Journal of Chemical Physics

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“…Pyridine in aqueous solution interacts with water essentially by forming hydrogen bonds, which involve the lone pair on the nitrogen atom of the heterocyclic compound with solvent . To validate the proposed model, in which the lone pair on nitrogen atom is explicitly described through the VS, the H‐bond interactions have been compared with a model without VS (hereafter NO_VS) and previous experimental and computational results. The first information on the hydrogen bond structure has been obtained by determining the radial pair distribution function, g(r), for the N

\dots

H and N

\dots

O contacts, reported in Figure .…”

Section: Resultsmentioning

confidence: 99%

“…[Color figure can be viewed at wileyonlinelibrary.com] FULL PAPER WWW.C-CHEM.ORG solvent. [82,83] To validate the proposed model, in which the lone pair on nitrogen atom is explicitly described through the VS, the H-bond interactions have been compared with a model without VS (hereafter NO_VS) and previous experimental [82,[84][85][86][87][88][89][90][91] and computational [92][93][94][95][96] results. The first information on the hydrogen bond structure has been obtained by determining the radial pair distribution function, g(r), for the NÁ Á ÁH and N. .…”

Section: Resultsmentioning

confidence: 99%

Electronic absorption spectra of pyridine and nicotine in aqueous solution with a combined molecular dynamics and polarizable QM/MM approach

et al. 2016

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The electronic absorption spectra of pyridine and nicotine in aqueous solution have been computed using a multistep approach. The computational protocol consists in studying the solute solvation with accurate molecular dynamics simulations, characterizing the hydrogen bond interactions, and calculating electronic transitions for a series of configurations extracted from the molecular dynamics trajectories with a polarizable QM/MM scheme based on the fluctuating charge model. Molecular dynamics simulations and electronic transition calculations have been performed on both pyridine and nicotine. Furthermore, the contributions of solute vibrational effect on electronic absorption spectra have been taken into account in the so called vertical gradient approximation.

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“…The origin of such demixing is often considered in relation to the ordered character of the hydration shell of a solute. [66,67] At low temperatures, a biomolecule is covered by the spanning water network, which can be considered as ordered and promoting solubility in water. This network breaks and becomes less ordered upon heating, which causes demixing at some temperature.…”

Section: Which Properties Of a Spanning Network Of Hydration Water Armentioning

confidence: 99%

Which Properties of a Spanning Network of Hydration Water Enable Biological Functions?

Brovchenko¹,

Oleinikova²

2008

ChemPhysChem

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The central role of water in biological functions is well-recognized, but numerous questions concerning the physical mechanisms behind the importance of water for life remain unanswered. Water in biosystems exists mainly as hydration water. Analysis of the phase diagram of hydration water shows that biological functions are possible only when the surfaces of biomolecules are covered by spanning hydrogen-bonded networks of hydration water. The comparative studies of the various properties of hydrated biosystems in the presence and in the absence of a spanning water network should clarify its specific physical properties, which are crucial for biological functions. Herein, we summarize the recent progress in these studies. The biological activity of the living organisms is maximal in a narrow temperature interval, where the spanning network of hydration water breaks up with heating via a percolation transition. The entropy of the hydration water related to the diversity of cluster size diverges at this percolation threshold. The possible role of this phenomenon in life processes is discussed.

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Structural changes of the molecular complexes of pyridines with water and demixing phenomena in aqueous solutions

Cited by 40 publications

References 46 publications

Freezing on heating of liquid solutions

Freezing on heating of liquid solutions

Electronic absorption spectra of pyridine and nicotine in aqueous solution with a combined molecular dynamics and polarizable QM/MM approach

Which Properties of a Spanning Network of Hydration Water Enable Biological Functions?

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