Intermolecular Interactions In Water Research Articles

Synergistic Effect of H‐bond Reconstruction and Interface Regulation for High‐Voltage Aqueous Energy Storage

AbstractAqueous cells have gained widespread attention for their low‐cost and safety. However, the 1.23 V thermodynamic stability window of water severely limits their development and application. To solve this issue, this study proposes and demonstrates that regulators can enhance and protect water molecules through hydrogen bond reconstruction and assist in solid electrolyte interface generation. The expanded electrochemical window enables the construction of aqueous symmetric capacitors and Nb18W16O93||LiMn2O4 aqueous lithium‐ion batteries with voltages both up to 2.6 V, while exhibiting considerable Coulombic efficiency and high cycle stability. It is shown that efficient regulation of interaction and electrochemical window can also be achieved by a regulator alone, without relying on the effect of salt itself or the extreme reduction of water content. This not only provides a simple and effective way to develop aqueous cells, but also provides a new understanding for the research and utilization of H‐bonds and intermolecular interactions in water.

Cation-π Interactions and Their Contribution to Mussel Underwater Adhesion Studied Using a Surface Forces Apparatus: A Mini-Review.

Mussel underwater adhesion is a model phenomenon important for the understanding of broader biological adhesion and the development of biomimetic wet adhesives. The catechol moiety of 3,4-dihydroxyphenyl-l-alanine (DOPA) is known to be actively involved in the mechanism of mussel underwater adhesion; however, other underwater adhesion mechanisms are also crucial. The surface forces apparatus (SFA) has often been used to explore the contributions of other mechanisms to mussel underwater adhesion; e.g., recent SFA-based nanomechanical studies have revealed that cation-π interactions, one of the strongest intermolecular interactions in water, are the pivotal interactions of adhesive proteins involved in underwater mussel adhesion. This mini-review surveys recent research on cation-π interactions and their contributions to strong mussel underwater adhesion, shedding light on some biological processes and facilitating the development of biomedical adhesives.

Investigation of the Effects of Solvents on the Structural, Electronic and Thermodynamic Properties of Rosiglitazone Based on Density Functional Theory

Rosiglitazone ( C18H19N3O3S ) is an anti-diabetic drug that reduces insulin resistance in patients with type 2 diabetes. The parameters (bond lengths and bond angles), HOMO, LUMO, HOMO-LUMO energy gap, dipole moment, thermodynamic properties, total energy and vibrational frequencies and intensities of the Rosiglitazone molecule in gas phase and in solvents (Water, Ethanol, DMSO and Acetonitrile) were calculated based on Density Functional Theory (DFT) using standard basis sets: B3LYP/6-31G(d,p), B3LYP/6-31+G(d,p) and B3LYP/6-31++G(d,p). Windows version of Gaussian 09 was used for all the calculations. From the results obtained, the solvents have little influence on the optimized parameters of the molecule. The highest HOMO value of -5.433 eV was found in gas phase showing that the molecule will best donate electron in the gas phase, followed by ethanol in comparison with other solvents. The values of the HOMO were observed to increase with the decrease in dielectric constants of the solvents across all the basis sets used. The lowest LUMO energy of -1.448 eV was found to be in ethanol which shows that the molecule will best accept electron in ethanol compared to the gas phase and other solvents. The largest HOMO-LUMO gap of 4.285 eV was found in water which shows its higher kinetic stability and less chemical reactivity compared to other solvents and in the gas phase. The chemical softness of the molecule was found to decrease as the dielectric constants of the solvents increased namely from ethanol to water. The chemical hardness was found to slightly increase with the increase in dielectric constants of the solvents. The highest value of the dipole moment of 4.6874 D was found in water indicating that the molecule will have the strongest intermolecular interactions in water compared to other solvents and in the gas phase. The total energy increased as the dielectric constants of the solvents decreased from water to ethanol. The vibrational frequencies and intensities increased as the dielectric constants of the solvents increased from ethanol to water. The results confirmed the effects of solvents on the structural, electronic and thermodynamic properties of the studied molecule and will be useful in the design and development of rosiglitazone as an anti-diabetic drug.

Intermolecular Interactions in Water–Acetonitrile Solutions of Quinoline

The structure of water–acetonitrile solutions of derivatives of quinoline and tetrahydroquinoline is investigated by means of аb initio molecular dynamics. It is shown that the propensity of molecules to form different types of hydrogen bonds depends largely on both the nature of the functional groups and on steric factors. When porous graphitic carbon is used as a sorbent, a linear correlation is observed between the fraction of configurations with hydrogen bonds and the logarithm of the retention factor under conditions of reverse-phase liquid chromatography.

Why physicochemical properties of aqueous solutions of various compounds are linearly interrelated

Analysis of physicochemical properties, such as water activity, osmotic coefficients, surface tension, viscosity, and relative permittivity, of aqueous solutions of different inorganic salts, organic compounds, and polymers shows that these properties are linearly interrelated and this interrelationship may be described as: Yi1(ci1)=k1+k2Yi2(ci2)+k3Yi3(ci3), where Yi1(ci1), Yi2(ci2), and Yi3(ci3) are properties of aqueous solutions of individual compounds 1, 2, and 3 at the same ith concentration i of each compound (ci1=ci2 = ci3); k1, k2, and k3 are constants. The relationship holds for various concentrations of compounds provided properties of aqueous solutions of the individual compounds are compared at the same concentration of each compound. Similar interrelationships are established also between different properties of aqueous solutions of any given compound. It is suggested that the reason for these relationships is that all physicochemical properties of aqueous solutions of any compound display different aspects and peculiarities of intermolecular water-water interactions affected by the presence of the compound, its nature, and concentration. The different types of water-water interactions in aqueous solutions may be quantified with the solvatochromic dyes. The solvent dipolarity/polarizability, π*, hydrogen bond donor acidity, α, and hydrogen bond acceptor basicity, β of water reported previously for aqueous solutions of organic compounds and polymers as well as those obtained for solutions of inorganic salts are linearly interrelated likely due to the cooperativity of intermolecular interactions in water. It is shown that any physicochemical property of aqueous solution of a given salt, organic compound, or polymer may be described by linear combination of two solvent features, π* and α, or in some cases by a single solvent feature. This fact explains the reason for the existence of the aforementioned linear interrelationships between the physicochemical properties of aqueous solutions of different compounds.

Heterotypic Supramolecular Hydrogels.

Supramolecular hydrogels, formed via intermolecular interactions in water, are emerging as a new type of versatile soft materials to be applied in many areas, such as biomedical applications, catalysis, food additives, and cosmetics. While most of the supramolecular hydrogels are homotypic (i.e., one type of building blocks), heterotypic supramolecular hydrogels are less explored, but may offer unique advantages. This review discribes supramolecular hydrogels that consist of more than one type building blocks (i.e., heterotypic) to illustrate the promises and challenges of heterotypic supramolecular hydrogels as soft biomaterials. First, we discuss the driving force for producing heterotypic supramolecular hydrogels. Second, we introduce the general methods for triggering heterotypic supramolecular hydrogels. Third, we summarize the examples of heterotypic supramolecular hydrogels made of hydrogelators with or without containing amino acid residues. Fourth, we describe the applications of heterotypic supramolecular hydrogels up-to-date. Finally, we give the outlook and propose a few future directions that likely worth to be explored.

Understanding water and ion transport behaviour and permeability through poly(amide) thin film composite membrane

Molecular dynamics (MD) together with the adaptive biasing force (ABF) and metadynamics free energy calculation methods was used to investigate the permeation properties of salt water through poly(amide) thin film composite reverse osmosis membranes. The thin films were generated by annealing an amorphous cell of poly(amide) chains through an MD method. The MD results showed they have typical structural properties of the active layer of thin film composite membranes and comparable water diffusivity (2.13×10−5cm2/s for the film with a density of 1.06g/cm3) and permeability (9.27×10−15cm3cm/cm2sPa) to experimental data. The simulations of water permeation through the films under different transmembrane pressures revealed the behaviours of water molecules in the thin films and the dynamic regimes of water permeation, including Brownian diffusion, flush and jump diffusion regimes. The intermolecular interactions of water and ions with poly(amide) chains showed a strong dependence on the local structure of films. The attraction between water and ploy(amide) molecules can be up to 8.5kcal/mol in dense polymer regions and 5kcal/mol in the pores of about 3nm. The ABF and metadynamics simulations produced the profiles of free energy potential of water and ions along the depth of the thin films, which provided important information for quantitatively determining the barrier energy required for water permeation and rejection of ions. The thin film with a density of 1.06g/cm3 and a thickness of 6nm offers a rejection to Na+ but a slight absorption of Cl− (0.25kcal/mol) at 0.3–0.4nm distance to its surface. Water molecules must overcome 63kcal/mol energy to move to the centre of the film. The dependences of the barrier energy and the water–polymer interaction energy on the local free volume size in the thin film were analysed. The simulations of water permeation under high transmembrane pressures showed a nonlinear response of the concentration and distribution of water molecules in the film to the imposed pressure. Compaction of the film segments close to the porous substrate and water congestion in dense regions significantly influenced the water permeation when the membrane was operated under pressures of more than 3.0MPa.

The quasi-periodic character of intermolecular interactions in water

The dynamics of physical characteristics of water are studied using various methods of molecular structural analysis: IR spectroscopy, Raman spectroscopy, microwave radiometry, and nuclear magnetic resonance in the magnetic field of the Earth. The changes in the physical characteristics of water obey certain regularities. Similar and well-reproducible oscillation periods of the measured values are observed in all experiments, regardless of the method of analysis used. These periods are 1–3, 5–9, 10–13, 14–18, 21–29, 30–39, 41–55, and ∼60 min. The oscillation amplitudes vary up to 10%. Based on the two-structure model of water, the revealed quasi-periodic character of the intermolecular interactions may be related to the dynamics of mutual transitions between local structural inhomogeneities of water. It is proposed that the observed quasi-periodic character of the intermolecular interactions is due to spin isomerism of water molecules. The problems of the relationship between the oscillations of the physical properties of water and biorhythms are discussed.

Transition of chemically modified diphenylalanine peptide assemblies revealed by atomic force microscopy

Self-assembled structures from aromatic dipeptides have attracted a lot of attention. It is highly desirable to produce dipeptide assemblies which undergo structural transitions in response to external stimuli. In this paper, solid nanospheres were successful produced from the self-assembly of chemically modified diphenylalanine in hexafluoroisopropanol (HFIP), a highly polar solvent. Interestingly, after treatment with water, the nanospheres were transformed into nanofibers. The intermediate transition state of nanospheres embedded along the nanofibers was captured by atomic force microscopy (AFM) imaging. In addition, AFM-based nanomechanical measurement revealed the increased stiffness after the transition, suggesting enhanced molecular packing due to favoured intermolecular interactions in water. This study presents a new method to fabricate novel dipeptide structures and provides new information for understanding the mechanism of dipeptide self-assembly driving by intermolecular interactions.

Low-frequency Raman spectra in water and in weak aqueous solutions. Spatial inhomogeneity in hydrogen peroxide solution

We describe some examples of the study of intermolecular interactions in water and in weak aqueous solutions using the low-frequency Raman spectra. An improved method of determining parameters of the dynamic susceptibility from the Raman spectra is described. The nine spectral parameters (the intensity, the frequency and the width of the two oscillators, the intensity and the width of the relaxation motion and the intensity of fluorescent background) completely describe the spectrum in the frequency range of 4 to 320 cm(-1). For hydrogen peroxide the dependences of these parameters on the concentration is shown. Concentration dependence of the spectral parameters of the hydrogen peroxide solution in water indicates a change in the structure of the molecular bonds in water near a peroxide molecule at a distance up to 0.7-0.9 nm.The effect of the exciting laser radiation on the parameters of the spectra in the registration of the Raman spectra of water is shown.

Ice films follow structure zone model morphologies

Ice films deposited at temperatures of 6–220 K and at low pressures in situ in a cryo-environmental scanning electron microscope show pronounced morphologies at the mesoscale consistent with the structure zone model of film growth. Water vapour was injected directly inside the chamber at ambient pressures ranging from 10 − 4 Pa to 10 2 Pa. Several different substrates were used to exclude the influence of their morphology on the grown films. At the lowest temperatures the ice, which under these conditions is amorphous on the molecular scale, shows the mesoscale morphologies typical of the low-temperature zones of the structure zone model (SZM), including cauliflower, transition, spongelike and matchstick morphologies. Our experiments confirm that the SZM is independent of the chemical nature of the adsorbate, although the intermolecular interactions in water (hydrogen bonds) are different to those in ceramics or metals. At higher temperatures, on the other hand, where the ice is hexagonal crystalline on the molecular scale, it displays a complex palmlike morphology on the mesoscale.

The Water Forcefield: Importance of Dipolar and Quadrupolar Interactions

It is widely recognized that dipolar interactions play a fundamental role in water. Less emphasis is put on the effects dues to the quadrupole moment. The recent calculation of the phase diagram for several rigid, nonpolarizable water models has shown that this is a rather severe test for water potentials. In this work, we analyze the results yielded by popular three-point-charge water models (TIP3P, SPC, SPC/E, TIP4P, TIP4PEw, TIP4P/2005, and TIP4P/Ice) and attempt to correlate them with the molecular dipoles and quadrupoles. It is shown that the melting temperatures of the proton disordered ices depend almost linearly on the quadrupole moments. However, the relative stability of ice II with respect to ices III, V, and VI seems to be rather dependent on the ratio of dipolar/quadrupolar forces. Small departures from a given ratio increase the stability of ice II and result in a serious deterioration of the phase diagram. Simple expressions are derived for the dipole and quadrupole moments, which allow us to analyze the effect of these multipole moments in the phase diagram when the rest of the molecular parameters are fixed. Satisfactory results for both the melting temperatures and for the relative stability of the different ices are obtained only when the molecular quadrupole approaches that of the isolated water molecule. Or, expressed in terms of the model parameters, acceptable results require that the negative charge be shifted from the oxygen toward the hydrogen positions by 0.14 A or more. I. Introduction Water is probably the most studied substance in nature. This is not only a consequence of its importance in our everyday life, but it is also due to its peculiar behavior which makes it the target of a great number of theoretical investigations. Both sources of interest (theoretical and practical) are closely related since many industrial and biochemical processes ultimately rely on its unusual physicochemical properties. Hence, there is interest in an adequate description of the intermolecular interactions in water. The complexity of the water properties together with the different possible levels of description have led to the proposal of hundreds of models (see the excellent review by Guillot 1 for a critical analysis of the results yielded by these models). At first, it would seem feasible that an analytical fit of ab initio calculations of the potential energy surface (PES) of water dimers could provide accurate potential functions. 2 Unfortunately, the results did not confirm the expectations. This is because the procedure has a number of limitations. The first is due to the reduced number of points used to represent the potential energy surface. Besides, since the potential energy represents only a small fraction of the total energy of the system, the precision of the calculations may compromise the results. Moreover, calculations based on the water dimer or more complex water clusters do not necessarily give an accurate representation of water in condensed phases. For these reasons, most of the popular water models are still empirical. However, promising results have been recently obtained with more refined electronic calculations. This is the case, for instance, of the MCDHO model 3 obtained from a fit of a refined ab initio single molecule deformation PES. 4 These calculations provide quali

Predictions of the Properties of Water from First Principles

A force field for water has been developed entirely from first principles, without any fitting to experimental data. It contains both pairwise and many-body interactions. This force field predicts the properties of the water dimer and of liquid water in excellent agreement with experiments, a previously elusive objective. Precise knowledge of the intermolecular interactions in water will facilitate a better understanding of this ubiquitous substance.

Monte carlo investigations of intermolecular interactions in water–amide mixtures

Monte Carlo simulations of water–amides (amide=formamide—FOR, methylformamide—NMF and dimethylformamide—DMF) solutions have been carried out in the NpT ensemble at 308 K and 1 atm. The structure and excess enthalpy of the mixtures as a function of the composition have been investigated. The TIP4P model was used for simulating water and six-site models previously optimized in this laboratory were used for simulating the liquid amides. The intermolecular interaction energy was calculated using the classical 6–12 Lennard–Jones potential plus a Coulomb term. The interaction energy between solute and solvent has been partitioned what leads to a better understanding of the behavior of the enthalpy of mixture obtained for the three solutions experimentally. Radial distribution functions for the water–amides correlations permit to explore the intermolecular interactions between the molecules. The results show that three, two and one hydrogen bonds between the water and the amide molecules are formed in the FOR, NMF and DMF–water solutions, respectively. These H-bonds are, respectively, stronger for DMF–water, NMF–water and FOR–water. In the NMF–water solution, the interaction between the methyl group of the NMF and the oxygen of the water plays a role in the stabilization of the aqueous solution quite similar to that of an H-bond in the FOR–water solution.

Influence of isoleucyl dipeptide side-chains on the dissociation and intermolecular interactions in water at 298.15 K

Enthalpies of dissociation of four isoleucyl dipeptides having alkyl side-chains ( l-isoleucine-glycine, l-Ile-Gly; l-isoleucine- l-alanine, l-Ile- l-Ala; l-isoleucine- l-valine, l-Ile- l-Val; l-isoleucine- l-isoleucine, l-Ile- l-Ile) in water at 298.15 K have been determined. Enthalpies of dilution have also been calculated. These results were used to derive the enthalpic coefficients of interactions according to the modified McMillan–Mayer's model. The results are considered in an effort to establish a possible relation between dissociation, intermolecular interactions and the size of the alkyl side-chains.

Stability of Ag Cryptate in Mixed Solvent with Negative Deviations from Additivity

Coordination model of solvation was used to analyze the change in stability constants of Ag(I) cryptate in water–DMSO solvent. The resolvation constants, distribution of solvatocomplexes, and composition of solvation shells of Ag+ and 2.2.2-cryptand in a mixed solvent were determined and the effect of solvation of coordinating (reaction) centers of reagents on the stability of a complex was estimated. It was shown that specific intermolecular interactions of water and organic component of a mixed solvent should be taken into consideration when studying the equilibria of complexation in such systems.

Temperature dependences of intra- and inter-molecular interactions in water and 12-Crown-4 - a comparison

Intra-, inter-molecular (inter-bond) and Fermi resonance interactions in water and 12-Crown-4 are considered. The temperature dependences of the corresponding interaction constants, recently published in literature (Refs. 1,2), are compared. It is shown that the main reason for the existing differences in the temperature behaviour of the intramolecular and Fermi resonance interactions between water and crown is the presence of strong temperature dependent H bonds between water molecules and an absence of such or similar bonds between crown molecules. The similarity in the temperature behaviour of the intermolecular (interbond) interaction in water and in crown is because of the similar mechanisms of the intermolecular (interbond) coupling.

Intermolecular interactions in water

A review of different intermolecular interactions in water is reported in connection with the vibrational spectra of its hydrogen bonds.

Application of the polarization model to the study of phosphoric acid media

The polarization model, previously introduced to approximate both intramolecular and intermolecular interactions in water, has been extended to include pentavalent phosphorus. The extension appears to be successful in representing structures of simple compounds of P5+ with O2− and H+. The model has been applied to statistical mechanical study of liquid phospheric acid at 200 C, using the Monte Carlo method of computer simulation for 216-atom systems. Two versions of the simulation have been implemented corresponding to stoichiometrically equivalent but experimentally distinguishable materials: (a) 27 orthophosphoric acid molecules, and (b) a mixture of water and polyphosphoric acid. Pair correlation functions for all types of atom pairs, as well as details of acid dissociation statistics, have been computed for both materials.