Analysis of weakly bound structures: hydrogen bond and the electron density in a water dimer

Bartha, F.; Kapuy, Orsolya; Kozmutza, C.; Alsenoy, C. Van

doi:10.1016/j.theochem.2003.08.020

Cited by 37 publications

(27 citation statements)

References 18 publications

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“…The absence of a clear connection between steric constraint and H-bond strength led us to focus on electrostatic interactions, because water H bonds are predominantly electrostatic in nature (41). H bonds in water are known to be strongly cooperative (23,(42)(43)(44); their strength, therefore, depends on electrostatic interactions of an H-bonded pair with neighboring water molecules.…”

Section: Ir Spectroscopy Of Water Molecules In the Neighborhood Of Pumentioning

confidence: 99%

Origin of hydrophobicity and enhanced water hydrogen bond strength near purely hydrophobic solutes

Grdadolnik

Merzel

Avbelj

2016

Proc. Natl. Acad. Sci. U.S.A.

201

145

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Hydrophobicity plays an important role in numerous physicochemical processes from the process of dissolution in water to protein folding, but its origin at the fundamental level is still unclear. The classical view of hydrophobic hydration is that, in the presence of a hydrophobic solute, water forms transient microscopic "icebergs" arising from strengthened water hydrogen bonding, but there is no experimental evidence for enhanced hydrogen bonding and/or icebergs in such solutions. Here, we have used the redshifts and line shapes of the isotopically decoupled IR oxygen-deuterium (O-D) stretching mode of HDO water near small purely hydrophobic solutes (methane, ethane, krypton, and xenon) to study hydrophobicity at the most fundamental level. We present unequivocal and model-free experimental proof for the presence of strengthened water hydrogen bonds near four hydrophobic solutes, matching those in ice and clathrates. The water molecules involved in the enhanced hydrogen bonds display extensive structural ordering resembling that in clathrates. The number of ice-like hydrogen bonds is 10-15 per methane molecule. Ab initio molecular dynamics simulations have confirmed that water molecules in the vicinity of methane form stronger, more numerous, and more tetrahedrally oriented hydrogen bonds than those in bulk water and that their mobility is restricted. We show the absence of intercalating water molecules that cause the electrostatic screening (shielding) of hydrogen bonds in bulk water as the critical element for the enhanced hydrogen bonding around a hydrophobic solute. Our results confirm the classical view of hydrophobic hydration.hydrophobic hydration | hydrogen bonding | IR spectroscopy | electrostatic screening | ab initio molecular dynamics D espite its great importance in numerous phenomena, the origin of hydrophobicity remains one of the most disputed topics in science (1-5). Experimental studies have shown that small purely hydrophobic solutes (alkanes and noble gases) in water increase the order (6, 7) and restrict the mobility (8) of neighboring water molecules. There are several opposing views on how to explain these data. The classical view is that a solute modifies water structure by forming transient, semiordered clathrate-like clusters ("icebergs"; used here only as a loose term) around it, arising from enhanced water hydrogen bonding (H bonding) (6, 7). This enhancement is brought about by either strengthening (9) or increasing the number of water to water H bonds (10). The classical view explains the characteristic changes in the thermodynamic variables of hydrophobic hydration (positive ΔG, ΔC p , negative ΔS, and ΔH) and the restricted mobility of water molecules observed by NMR (8). Neutron diffraction (11, 12) and extended X-ray absorption fine structure (EXAFS) (13) studies, however, show that the water molecules around small purely hydrophobic molecules do not differ significantly from those in pure liquid water. According to the dynamic view, the hydrophobic solute causes slowdown of t...

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Section: Ir Spectroscopy Of Water Molecules In the Neighborhood Of Pumentioning

confidence: 99%

Origin of hydrophobicity and enhanced water hydrogen bond strength near purely hydrophobic solutes

Grdadolnik

Merzel

Avbelj

2016

Proc. Natl. Acad. Sci. U.S.A.

201

145

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“…Cooperative hydrogen bonding increases the O-H bond length, at the same time causing a reduction in the H…O and O…O distances [33]. The protons held by individual H 2 O molecules may switch partners in an ordered manner within hydrogen networks [34]. As the result, aqueous solutions may undergo autoprotolysis, i.e.…”

Section: The Evaluation Of the Mathematical Model Of Interaction Of Tmentioning

confidence: 99%

The Evaluation of the Mathematical Model of Interaction of Electrochemically Activated Water Solutions (Anolyte and Catholyte) with Water

Ignatov¹,

Mosin²,

Toshkova³

et al. 2015

European Reviews of Chemical Research

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This paper deals with the evaluation of the basis of the mathematical model of interaction of electrochemically activated water solutions (catholyte/anolyte), obtained in the diaphragm electrolysis cell, with water and sodium chloride and the basic physical-chemical processes underlying the electrolysis of water as well. In order to provide additional data about the distribution of H 2 O molecules according to the energies of hydrogen bonds in the electrochemically activated water solutions of the catholyte and the anolyte, the non-equilibrium energy spectrum 72 European Reviews of Chemical Research, 2015, Vol.(4), Is. 2 (NES) and differential non-equilibrium energy spectrum (DNES) of the anolyte and the catholyte were measured as a result of which were established the basis for evaluation of the mathematical model explaining the behavior of the anolyte and the catholyte regarding the distribution of H 2 O molecules to the energies of hydrogen bonds. The local maximum for catholyte in the NESspectrum was at -0,1285 eV, for anolyte -at -0,1227 eV and for the control sample of deionized water -at -0,1245 eV. The calculations of ∆E H...O for catholyte with using the DNES method compiles (-0,004±0,0011 eV) and for anolyte (+1,8±0,0011 eV). The average energy of hydrogen bonds between Н 2 О molecules was measured by the DNES method to be compiled at -0,1067±0,0011 eV.Keywords: electrochemical treatment of water, electrolysis, anolyte, catholyte, NES, DNES. IntroductionThe phenomenon of electrochemical activation of water (EAW) is a set of electrochemical and electrical processes occur in water in the electric double layer (EDL) type of electrodes (anode and cathode) with non-equilibrium electric charge transfer through EDL by electrons under the intensive dispersion in water the gaseous products of electrochemical reactions [1]. In 1985 EAW was officially recognized as a new class of physical and chemical phenomena.As a result of the treatment of water by a constant electric current at electric potentials equal to or greater than the decomposition potential of water (1,25 V), water goes into a metastable state, accompanied by electrochemical processes and characterized by the abnormal activity levels of electrons, the redox potential, and other physical-chemical parameters (pH, Eh, ORP) [2].During the EAW occur four main processes: 1) Electrolytical decomposition of water by electrolysis on account of redox reactions on the electrodes due to the external electric field;2) Electrophoresis -the movement in the electric field of a positively charged particles and ions toward the cathode and negatively charged particles and ions toward the anode;3) Electroflotation -the gas formation and flocculation of aggregates consisting of finedispersed gas bubbles (H 2 at the cathode and O 2 at the anode) and suspended solids in water; 4) Electrocoagulation -the formation of colloidal aggregates of particles of deposited disperse phase through a process of anode dissolution of the metal and the formation of metal cations Al...

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“…Cooperative hydrogen bonding increases the O-H bond length, at the same time causing a reduction in the H…O and O…O distances. The protons held by individual H2O molecules may switch partners in an ordered manner within hydrogen networks [10]. As the result, aqueous solutions may undergo autoprotolysis, i.e.…”

Section: Nature Of Hydrogen Bond In Water and Icementioning

confidence: 99%

Structural Models of Water and Ice Regarding the Energy of Hydrogen Bonding

Ignatov¹,

Mosin²

2015

Nanotechnology Research and Practice

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In this review it is reported about the research on the structure of water and ice and intermolecular water cyclic associates (clusters) with general formula (Н 2 О) n and their charged ionic clusters [(Н 2 О) n ] + and [(Н 2 О) n ] -by means of computer modelling and spectroscopy methods as 1 Н-NMR, IR-spectroscopy, DNES, EXAFS-spectroscopy, X-Ray and neurons diffraction. The computer calculation of polyhedral nanoclusters (Н 2 О) n , where n = 3-20 are carried out. Based on this data the main structural mathematical models describing water structure (quasicrystalline, continious, fractal, fractal-clathrate) have been examined and some important physical characteristics were obtained. The average energy of hydrogen bonding (∆E H…O ) between Н 2 О molecules in the process of cluster formation was measured by the DNES method compiles -0,1067±0,0011 eV. It was also shown that water clusters formed from D 2 О were more stable, than those ones from Н 2 О due to isotopic effects of deuterium.

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Analysis of weakly bound structures: hydrogen bond and the electron density in a water dimer

Cited by 37 publications

References 18 publications

Origin of hydrophobicity and enhanced water hydrogen bond strength near purely hydrophobic solutes

Origin of hydrophobicity and enhanced water hydrogen bond strength near purely hydrophobic solutes

The Evaluation of the Mathematical Model of Interaction of Electrochemically Activated Water Solutions (Anolyte and Catholyte) with Water

Structural Models of Water and Ice Regarding the Energy of Hydrogen Bonding

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