Effects of Hydrogen Bonding on the Transition Properties of Ethanol–Water Clusters: A TD-DFT Study

Relationship Between Fluorescent and Vibronic Properties of Detonation Nanodiamonds and Strength of Hydrogen Bonds in Suspensions

“…Ethanol molecules are located inside a shell of water molecules making this shell stronger and ordered. , In a water–ethanol solution with an ethanol concentration of 70 vol %, the hydrogen bonds are, on the contrary, much weaker in comparison with those in pure water. These results were obtained both in theoretical calculations and during study of the water–ethanol solutions using calorimetrical methods, NMR, FTIR, and Raman spectroscopy. − Estimations of the energy of hydrogen bonds in water and water–ethanol solutions with ethanol concentrations of 20 vol % and 70 vol % have been performed . Enthalpy of hydrogen bonds in the specified solutions was Δ H w = (−21.4 ± 0.7) kJ/mol, Δ H 20% = (−24.5 ± 0.8) kJ/mol, and Δ H 70% = (−16.2 ± 0.8) kJ/mol, respectively.…”

“…The selection was based upon the fact that in water–ethanol solutions at an ethanol concentration of approximately near 20 vol % self-organization of ethanol and water molecules is observed. It leads to amplification of hydrogen bonds in the solution in comparison with pure water (the effect of stabilization of the water structure). − …”

Raman Spectroscopy of Water–Ethanol Solutions: The Estimation of Hydrogen Bonding Energy and the Appearance of Clathrate-like Structures in Solutions

“…Such data interpretation contradicts the views of other authors describing water structure as more ordered near hydrophobic headgroups of the alcohol. The majority of experts came to the conclusion that, as a result of hydrophobic hydration in water–ethanol solutions, the self-organization of molecules is observed, resulting in formation of various molecular associates including clathrate-like structures. ,,,− The aberrant thermodynamic properties are explained by the structural features of water and alcohol mixtures, including different the strength of the hydrogen bond between water–water, alcohol–alcohol, and alcohol–water molecules. The problem lies in understanding how hydrophobic interactions between the alkyl headgroups of alcohol molecules as well as hydrogen bonding between the hydroxyl groups of water and alcohol molecules “help” each other to create various structural associates in the mixtures.…”

“…Many theoretical calculations indicate the existence of stable water–ethanol complexes in water–ethanol solutions. ,− The calculations of Matsugami et al of hydrogen bonding in water–ethanol solutions using the method of molecular dynamics showed that at the mole fraction of ethanol x Et ≈ 0.20 the hydrogen bonds in solution increase. To explain the anomalous negative excess entropy of mixing ethanol and water, Soper et al proposed the clustering model. , This model supposes the formation of clusters of water molecules in the presence of alcohol component in the whole range of ethanol solubility.…”

Specific Anion Effect in Water–Nonaqueous Solvent Mixtures: Interplay of the Interactions between Anion, Solvent, and Polymer

“…One can imagine that the formation of hydrogen bonds in water–organic solvent mixtures would be quite different if the added organic solvents only have hydrogen bond acceptors. − Dimethylsulfoxide (DMSO) is a widely used polar aprotic organic solvent, which is composed of a strongly polar sulfoxide group and two hydrophobic methyl groups. Thus, it can only act as the hydrogen bond acceptor.…”