Description of the spatial networks of hydrogen bonds in liquids by topological methods

Solutions of Urea and Tetramethylurea in Formamide and Water: A Comparative Analysis of Volume Characteristics and Solute–Solute Interaction Parameters at Temperatures from 288.15 to 328.15 K and Ambient Pressure

“…Recently, using precision densimetry, we have studied the volume-related pairwise interaction and solvation characteristics for tetramethylurea (TMU) and urea (U) as solutes in ethylene glycol (EG). The latter, being the simplest diol, is one of the organic solvents where a spatial network of hydrogen bonds is tended to the “waterlike” structure transformations around a predominantly hydrophobic solute (such as TMU), a phenomenon defined as the solvophobic solvation. ,,− As it was concluded in ref increasing structure compactness in the “solvation complex” of both TMU and hydrophilic U on going from EG to water can be serving as a corroboration of the fact that the intermolecular hydrogen bonding in aqueous solutions is more stable. ,, At the same time, the structure-making effect in aqueous TMU, being in terms of the solvophobic solvation and pairwise solvophobic interaction, is much more pronounced than it does in the (EG + TMU) system while the structure-breaking effects in the compared solutions of U are differed not as significant. These inferences are in agreement with the results drawn from the calorimetry study performed previously by one of us (A.V.…”

“…3,8,16−20 As it was concluded in ref 19 increasing structure compactness in the "solvation complex" of both TMU and hydrophilic U on going from EG to water can be serving as a corroboration of the fact that the intermolecular hydrogen bonding in aqueous solutions is more stable. 3,14,16 At the same time, the structuremaking effect in aqueous TMU, being in terms of the solvophobic solvation and pairwise solvophobic interaction, is much more pronounced than it does in the (EG + TMU) system while the structure-breaking effects in the compared solutions of U are differed not as significant. These inferences are in agreement with the results drawn from the calorimetry study performed previously by one of us (A.V.…”

“…The hydrophobic effects including phenomena of hydrophobic hydration and hydrophobic interactions, as is known, are directly associated with the existence of the open three-dimensional hydrogen-bond network in liquid water. Its smallest triatomic molecule forms four H bonds directed along the tetrahedron. − Such a spatially coordinated structure of the aqueous matrix is fairly labile and elastic to accommodate a hydrophobic particle (or moiety) of moderate size, facilitating simultaneously the association of “nonequivalent species” in the regions of defective hydrogen bonding. − The evidence of solvophobic effects in H-bonded nonaqueous (organic) media seems quite speculative. − Formally, to form the spatial network of directed hydrogen bonds in liquids, it is necessary that a solvent molecule has at least two proton donor centers and two proton acceptor ones. , A rather few groups of organic solvents (diamines, amino alcohols, diols, glycerol, etc.) satisfy these requirements.…”

“…9−13 Formally, to form the spatial network of directed hydrogen bonds in liquids, it is necessary that a solvent molecule has at least two proton donor centers and two proton acceptor ones. 3,14 A rather few groups of organic solvents (diamines, amino alcohols, diols, glycerol, etc.) satisfy these requirements.…”

Description of the hydrogen bond network in liquid 3-amino-1-propanol by graph theory and percolation methods

“…The objective of this work was to describe the spatial network of hydrogen bonds of liquid 3-amino-1-propanol using graph theory and percolation and compare the data with the results of a similar description of monoethanolamine (MEA), which we obtained earlier [5], as well as with similar calculations in the series of diols. Fig.…”