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Starting from (p‐tolylsulfinyl)ferrocene (1), a mixture of the complete series [CpFe{C5H5–n(SOTol‐p)n}] (n = 2–4) (2–4) in all regioisomers was obtained. After chromatographic separation, crystals of 1,2‐bis[(4‐methylbenzene)sulfinyl]ferrocene, 2a, and 1,3‐bis[(4‐methylbenzene)sulfinyl]ferrocene, 2b, both [Fe(C5H5)(C19H17O2S2)], as well as of 1,2,3‐tris[(4‐methylbenzene)sulfinyl]ferrocene, [Fe(C5H5)(C26H23O3S3)], 3a, and 1,2,3,4‐tetrakis[(4‐methylbenzene)sulfinyl]ferrocene ethyl acetate 0.75‐solvate, [Fe(C5H5)(C33H29O4S4)]·0.75C4H8O2, 4, could be isolated. Their molecular and crystal structures are compared with each other and also with the so far unreported structures of related 1,2‐bis(phenylsulfanyl)ferrocene, [Fe(C5H5)(C17H13S2)], 5, and 1,2,3,4‐tetrakis(phenylsulfanyl)ferrocene, [Fe(C5H5)(C29H21S4)], 6. In all the sulfinyl structures, the O atoms of the S=O groups are in equatorial positions, except for that in tetrasubstituted 4. All the arene rings of these compounds (except for one ring in 4) are in axial positions directed away from the Fe atom, mostly in a near perpendicular orientation with respect to the plane of the cyclopentadienyl ring. The main intermolecular interactions in the crystals are C—H...H—C, C—H...π and C—H...O, while C—H...S interactions are much less important, except for tetrasulfanyl compound 6. π–π interactions (intramolecular) are only important in compound 3a. Hirshfeld analysis shows that dispersion terms are dominant for the interaction energies of all six compounds. In general, the calculated total interaction energies increase with increasing number of substituents and are higher for the sulfinyl than for the sulfanyl groups. [ABSTRACT FROM AUTHOR]

This work conducts a comprehensive theoretical study on the non‐covalent complexation between cyclocarbons and C60 fullerene for the first time. The binding energy between cyclocarbons and C60 fullerene is significantly stronger than that between two C18 or two C60 fullerenes, indicating a particularly strong affinity. The cyclocarbons and C60 fullerene can spontaneously assemble into complexes in the gas phase at room temperature, and the hydrophobic effect caused by the solvent environment can promote this binding. The binding strength with C60 fullerene increases almost linearly with the increase of cyclocarbon size, and the C34@C60 dimer exhibits a perfect nano‐Saturn structure. As the ring size increases, the angle between the two cyclocarbons of the 2 : 1 trimers formed by cyclocarbons and C60 fullerene gradually decreases. In C60@2 C34 trimer, the fullerene is symmetrically surrounded by two cyclocarbons. The results on the trimers formed by cyclocarbon and C60 fullerenes in a 1 : 2 ratio showed when the cyclocarbon sandwiched between two fullerenes is not quite large, the trimers exhibit an ideal dumbbell‐like structure, and the presence of the first fullerene has a significant synergistic effect on the binding of the second one. The cyclocarbon greatly promotes the dimerization of fullerenes, which acted as a "molecular glue". [ABSTRACT FROM AUTHOR]

To reveal the mechanism of interaction between styrene−butadiene rubber (SBR) modifier and asphalt components, the molecular dynamics (MD) method was used to study the diffusion behaviour at different temperatures. The diffusion behaviour was discussed using radial distribution function (RDF), mean square displacement (MSD), and relative concentration (RC). Interaction energy was used to verify the accuracy of the simulations. The simulated results indicate that the order of the four asphalt components prone to aggregation with SBR is as follows: saturated >aromatics >asphaltene >resins. The interaction between SBR modifier and asphalt components affects the diffusion of asphalt components. At 160°C, the distribution of components is the most uniform. When the temperature is too low or too high, the components dissociate from each other. The results of interaction energy are consistent with the conclusion. This study reveals the mechanism of component interaction of SBR modified asphalt. [ABSTRACT FROM AUTHOR]

Solid-state drug delivery systems for the drug substances transport are of great importance nowadays. In the present work, the non-covalent interactions between taxifolin (Tax) and graphene as well as nitrogenated (N-doped) graphenes were systematically studied by using a wide set of theoretical techniques. Symmetry-adapted perturbation theory (SAPT0) calculations confirmed more favorable adsorption of Tax on N-doped graphenes compared to pristine graphene. It was established that dispersion interactions play the main role in the attractive interactions (>60%), whereas electrostatic and induction forces contribute only moderately to the attraction (~25% and 7–8%, respectively). Independent gradient model (IGM) analysis visually demonstrated the existence of dispersion interactions and hydrogen bonding in the studied Tax complexes. Ab initio molecular dynamics calculations indicated stability of these complexes at different temperatures. Our results show that N-doped graphenes with the enhanced interaction energy (Eint) toward Tax are promising candidates for the technical realization of the targeted drug delivery systems. [ABSTRACT FROM AUTHOR]

Asphaltene deposition poses a significant threat to the safe production of crude oil as it tends to occur in forming porous media, wellbores, pipelines, and refining equipment. It is also responsible for the high viscosity of crude oil, making it challenging to recover heavy crude oil. This study investigates the impact of aliphatic chain length on asphaltene aggregation and the molecular properties of organic solvents and dispersants interacting with asphaltenes. To achieve this, two model asphaltenes, M1 and C5Pe, were used in molecular dynamics simulations using radial distribution function, root means square displacement, diffusion coefficient, solubility parameter, cohesion energy density, and interaction energy as characterization parameters. The simulations revealed that the aggregation onset of C5Pe and M1 occurs at 2–5 Å at room temperature and pressure, and π–π stacking is the primary mode of aggregation, with the presence of heteroatomic groups providing additional forces for stable aggregation. Additionally, it was found that the π–π interactions weakened with the increase of the side chain length. The study also investigated the molecular behavior of asphaltenes in six organic solvents and found that M1 was more soluble in aromatic solvents than C5Pe, and undesirable solvents could induce asphaltene aggregation. Furthermore, the effect of five dispersants on asphaltene aggregation was explored, with PIBSI, BEHP, B-DBSA, CTAB, and benzoic acid showing decreasing dispersing ability in that order at lower concentrations. However, at higher concentrations, the effect of some dispersants diminishes and triggers self-aggregation behavior. [ABSTRACT FROM AUTHOR]

The heat of mixing of some petrological relevant substitutions (i.e., Mg-Al, Si-Al, Mg-Ti, Mg-Ca, and Mg-Fe) was investigated systematically in silicates, titanates, tungstates, carbonates, oxides, hydroxides, and sulphates by density functional theory calculations (e.g., melilite, chlorite, biotite, brucite, cordierite, amphibole, talc, pseudobrookite, pyroxene, olivine, wadsleyite, ilmenite, MgWO4, ringwoodite (spinel), perovskite, pyrope-grossular, magnesite-calcite, MgO-CaO, anhydrous and different hydrated MgSO4). A specific substitution is characterised by different microscopic interaction energies in different minerals, e.g., the octahedral Mg-Al exchange on a single crystallographic site in pyroxene has a microscopic interaction energy that is more than twice compared to that in biotite. A comparative investigation of the heat of mixing using microscopic interaction energies on a single crystallographic site has the advantage that they are not influenced by cation ordering. They could be successfully correlated with the stiffnesses of the minerals, which in turn were scaled to the oxygen packing fraction, a parameter that is easily available for poorly investigated minerals. With this information, the interaction energies of a certain substitution can be transferred from minerals where they are well-known to mineral groups where they are less- or unknown. Using the cross-site terms and the microscopic interaction energies, the macroscopic interaction energies of the coupled substitution, e.g., Mg + Si = Al + Al, of biotite and pyroxene were calculated, which are, however, affected by cation ordering and different degrees of local charge balance, for which appropriate models are necessary. [ABSTRACT FROM AUTHOR]

To solve the problem of the oscillation stability of direct-driven wind-powered grid-connected systems with a low-voltage crossing control, a method of oscillation stability analysis for these systems, based on interactive energy, is proposed in this paper. Firstly, a dynamic energy model of a direct-driven wind-powered grid-connected system is established, considering a low-voltage traverse control. Secondly, the energy is divided into four parts—the line parameter energy, current inner loop energy, PLL energy, and current inner loop–PLL interaction energy—and the conduction path of the energy during a low-voltage crossing is described. On this basis, the aperiodic components of each energy path are analyzed, the stability level of the system is quantified, the influence of the different control parameters on the interactive energy dissipation is deduced, the key interactive control links affecting the stability of the system are screened, and the influence rules of the parameters are expounded. Finally, a direct-driven wind-powered grid-connected system model is built on the Rt-lab platform, and it is verified by a simulation test. The results show that the interaction energy generated by the interaction of the current inner loop and phase-locked loop is a key factor affecting the stability of the direct-driven wind-powered grid-connected system. The simulation test parameters of the control group were adjusted as the current inner loop's proportion parameter increased from 1.32 to 5.28, the current inner loop's integral parameter increased from 4.48 to 6.42, the PLL's proportion parameter decreased from 9.45 to 6.3, and the PLL's integral parameter decreased from 50.25 to 40.2. Both the theoretical and experimental results show that increasing the current inner loop's integral and proportion parameters can improve the stability level of the direct-driven wind-powered grid-connected system; reducing the phase-locked loop's proportion and integral parameters can also improve the stability level of the grid-connected system. [ABSTRACT FROM AUTHOR]

Determining binding affinities in protein–protein and protein–peptide complexes is a challenging task that directly impacts the development of peptide and protein pharmaceuticals. Although several models have been proposed to predict the value of the dissociation constant and the Gibbs free energy, they are currently not capable of making stable predictions with high accuracy, in particular for complexes consisting of more than two molecules. In this work, we present ProBAN, a new method for predicting binding affinity in protein–protein complexes based on a deep convolutional neural network. Prediction is carried out for the spatial structures of complexes, presented in the format of a 4D tensor, which includes information about the location of atoms and their abilities to participate in various types of interactions realized in protein–protein and protein–peptide complexes. The effectiveness of the model was assessed both on an internal test data set containing complexes consisting of three or more molecules, as well as on an external test for the PPI‐Affinity service. As a result, we managed to achieve the best prediction quality on these data sets among all the analyzed models: on the internal test, Pearson correlation R = 0.6, MAE = 1.60, on the external test, R = 0.55, MAE = 1.75. The open‐source code, the trained ProBAN model, and the collected dataset are freely available at the following link https://github.com/EABogdanova/ProBAN. [ABSTRACT FROM AUTHOR]

In order to explore the micro-mechanism of the influence of anionic surfactant and nonionic surfactant on the wettability of low-rank coal, the molecular dynamics simulation method (MD) was used to study the influence of anionic surfactant (SDS), nonionic surfactant (AEO3) and their complex system on the wettability of lignite. The results show that when SDS is compounded with AEO3, the thickness of coal/water adsorption layer is 36.35×10−10 m, which wets 58.83% of lignite molecular layer. At this time, the diffusion coefficient of water molecules increases significantly, thus increasing the probability of collision between coal and water molecules, and further enhancing the wettability of water on lignite. In SDS/ AEO3 compound system, the interaction energy between lignite and water and between surfactant and water is greater than that of SDS and AEO3 alone. The interaction energy between coal and water, surfactant and water are all provided by non-bond energy, and the electrostatic energy accounts for more than 82.28% of the non-bond energy, while the contribution of Van der Waals’ force energy is very small, even inhibiting the interaction between surfactant and water. There is little difference in the length of hydrogen bonds between SDS, AEO3 and SDS/ AEO3, but the number of hydrogen bonds between SDS/ AEO3 and water is more than that SDS and AEO3 separated produced with water.

We have investigated the basic mechanism of carbon nanotube (CNT) interactions with various room-temperature ionic liquids (RTILs) using molecular dynamics (MD) simulations. To understand the effects of the cation molecular geometry on the properties of the interface structure in the RTIL systems, we have studied a set of three RTILs with the same [BF4]- (tetrafluoroborate) anion but with different cations, namely, [EMIM]+ (1-ethyl-3-methylimidazolium), [BMIM]+ (1-butyl-3-methylimidazolium), [HMIM]+ (1-hexyl-3-methylimidazolium), and [OMIM]+ (1-octyl-3-methylimidazolium) ions. The simulation results showed that the imidazolium cations exhibit two distinct orientations (perpendicular and parallel to the CNTs surface) at the interface irrespective of the alkyl chain length of the cations. The average number of hydrogen bonds per cations inside the CNT was found to be higher for [OMIM][BF4] (1.01), which suggests that [OMIM]+ imidazolium rings to be concentrated at the center of the CNT, which favors hydrogen bond. The reported results show the diffusion coefficients of ions in confinement are much lower in comparison to the bulk region. The interaction energy between [OMIM][BF4] (-8.75 kcal.mol−1.ion−1) and CNT was found to be higher as compared to other ILs. The cations paralleling the CNT surface are thermodynamically significantly more stable because of the substantial interfacial π-π stacking interactions, as shown by a comparison with the calculated interaction energies between cations and the CNTs. Our simulation results provide a molecular-level understanding of the stabilization and dispersion of CNT bundles in ILs. [ABSTRACT FROM AUTHOR]

This is an article in the field of metallurgical engineering. In order to explore the leaching mechanism of zinc oxide from zinc-containing dust by choline chloride and oxalic acid, the interaction of choline chloride and oxalic acid with 1∶1 and 1∶2 eutectic solvent on zinc oxide surface was simulated by means of quantum mechanics, and the simulation results were verified by experiments. The results show that the intermolecular hydrogen bond formed by choline chloride and oxalic acid plays an important role in the stability of eutectic solvent. Ch+ gains electrons, OA and Cl- lose electrons. ZnO(001) surface is the complete cleavage surface of zinc oxide, oxygen and zinc atoms form tetrahedral structure, oxygen atom is easy to gain electrons and zinc atom is easy to lose electrons during the reaction with the outside world. The zinc oxide loses electrons during the interaction between cholinergic chloride-oxalic acid and zinc oxide, and cholinergic chloride-oxalic acid gains electrons. The interaction energy △E=-819.6896Ha between ChCl-2OA and ZnO is small, indicating that zinc oxide is more likely to react with ChCl-2OA. The radial distribution function shows that the chemical adsorption is the main factor in the interaction between choline chloride and oxalic acid and zinc oxide, and the physical adsorption is the secondary factor. The contribution of Cl-Zn formed by chemical adsorption is greater than that of O-Zn. Through the pure mineral test, it can be verified that ChCl-2OA has a better leaching effect on zinc oxide, which verifies the accuracy of molecular simulation of the interaction mechanism between choline chloride and oxalic acid and zinc oxide, and provides a theoretical basis for the leaching of zinc-containing dust with eutectic solvent.

Solid-state drug delivery systems for the drug substances transport are of great importance nowadays. In the present work, the non-covalent interactions between taxifolin (Tax) and graphene as well as nitrogenated (N-doped) graphenes were systematically studied by using a wide set of theoretical techniques. Symmetry-adapted perturbation theory (SAPT0) calculations confirmed more favorable adsorption of Tax on N-doped graphenes compared to pristine graphene. It was established that dispersion interactions play the main role in the attractive interactions (>60%), whereas electrostatic and induction forces contribute only moderately to the attraction (~25% and 7–8%, respectively). Independent gradient model (IGM) analysis visually demonstrated the existence of dispersion interactions and hydrogen bonding in the studied Tax complexes. Ab initio molecular dynamics calculations indicated stability of these complexes at different temperatures. Our results show that N-doped graphenes with the enhanced interaction energy (Eint) toward Tax are promising candidates for the technical realization of the targeted drug delivery systems.

This is an article in the field of metallurgical engineering. In order to better realize the leaching of zinc oxide from zinc-containing dust, Materials Studio software based on density functional theory was used to simulate and optimize the crystal structure of zinc oxide and the structure of three kinds of choline deep eutectic solvents, and the mutual adsorption model of the two was calculated. The calculated results show that the ZnO(001) plane is a complete cleavage plane, and the highest occupied state near the Fermi level shifts to the left, and the peak of the highest occupies state increases, and the p orbital of O and the d orbital of Zn are more active, which are the active sites of the ZnO(001) plane. Optimization of three choline hyper eutectic solvent shows that choline chloride forms multiple intermolecular hydrogen bonds with three different hydrogen bond donors centered on chlorine atom. The adsorption model of deep eutectic solvents and zinc oxide was calculated using Forcite module. The results shows that the interaction strength of zinc oxide with three choline deep eutectic solvent is Chcl-MA >Chcl-Urea>Chcl-Eg. The radial distribution function shows that malonic acid makes it easier for Cl in choline chloride to chemisorb with Zn. In the three kinds of hydrogen bond donors, the activity of oxygen atomic functional groups forming chemical bonds with Zn is C=O, N-O and C-O, indicating that C=O in malonic acid makes the combination of Chcl-MA and ZnO more stable. Results show that the leaching temperature of Chcl-MA is 70 ℃ and the liquid-solid ratio is 10∶1. Under the condition of leaching time of 1 h for 60 min, single mineral zinc oxide can be almost completely leached, and the leaching effect is far greater than that of Chcl-Urea and Chcl-Eg, thus proving the accuracy of molecular simulation and providing theoretical guidance for the leaching of zinc-containing dust in choline deep eutectic solvent.

Abstract Expansive soils are known to be hazardous materials for infrastructure due to their high shrinking or swelling potential. Understanding the shrinking factors of expansive soils such as montmorillonite (MMT) is essential for predicting their mechanical properties. The interactions between the components of Na-MMT clays, e.g., MMT layer–layer (LL), layer–cation (LC), layer–water (LW) and water–cation (WC), are responsible for its shrinking behavior. In this study, molecular dynamics simulation and grand canonical Monte Carlo simulations are used to investigate the interaction energy evolution in the layered structure of Na-MMT for the shrinkage mechanisms analysis of clay. The results of simulation indicate that the magnitude of the interaction energy contributed by the interlayer cations dehydration is the driving force of the interlayer shrinkage. Furthermore, in the hydrated state, with one water layer, two water layers and three water layers, the attractive interactions between WC and LW, maintain the stability of the clay layers. However, at the dry state, the interaction energy between layers and cations appears to be the most essential component in holding the stacked layers together, which provides structural stability to the clay sheets. Finally, the study reveals that intermolecular interactions contribute to the mechanical properties of clays such as cohesive and elastic properties.

The benzene dimer (BD) is an archetypal model of π∙∙∙π and C–H∙∙∙π noncovalent interactions as they occur in its cofacial and perpendicular arrangements, respectively. The enthalpic stabilization of the related BD structures has been debated for a long time and is revisited here. The revisit is based on results of computations that apply the coupled-cluster theory with singles, doubles and perturbative triples [CCSD(T)] together with large basis sets and extrapolate results to the complete basis set (CBS) limit in order to accurately characterize the three most important stationary points of the intermolecular interaction energy (ΔE) surface of the BD, which correspond to the tilted T-shaped (TT), fully symmetric T-shaped (FT) and slipped-parallel (SP) structures. In the optimal geometries obtained by searching extensive sets of the CCSD(T)/CBS ΔE data of the TT, FT and SP arrangements, the resulting ΔE values were −11.84, −11.34 and −11.21 kJ/mol, respectively. The intrinsic strength of the intermolecular bonding in these configurations was evaluated by analyzing the distance dependence of the CCSD(T)/CBS ΔE data over wide ranges of intermonomer separations. In this way, regions of the relative distances that favor BD structures with either π∙∙∙π or C–H∙∙∙π interactions were found and discussed in a broader context. [ABSTRACT FROM AUTHOR]

Thermal recovery techniques for producing oil sands have substantial environmental impacts. Surfactants can efficiently improve thermal bitumen recovery and reduce the required amount of steam. Such a technique requires solid knowledge about the interaction mechanism between surfactants, bitumen, water, and rock at the nanoscale level. In particular, oil sands ores have extremely complex mineralogy as they contain many clay minerals (montmorillonite, illite, kaolinite). In this study, molecular dynamics simulation is carried out to elucidate the unclear mechanisms of clay minerals contributing to the bitumen recovery under a steameanionic surfactant co-injection process. We found that the clay content significantly influenced an oil detachment process from hydrophobic quartz surfaces. Results reveal that the presence of montmorillonite, illite, and the siloxane surface of kaolinite in nanopores can enhance the oil detachment process from the hydrophobic surfaces because surfactant molecules have a stronger tendency to interact with bitumen and quartz. Conversely, the gibbsite surfaces of kaolinite curb the oil detachment process. Through interaction energy analysis, the siloxane surfaces of kaolinite result in the most straightforward oil detachment process. In addition, we found that the clay type presented in nanopores affected the wettability of the quartz surfaces. The quartz surfaces associated with the gibbsite surfaces of kaolinite show the strongest hydrophilicity. By comparing previous experimental findings with the results of molecular dynamics (MD) simulations, we observed consistent wetting characteristics. This alignment serves to validate the reliability of the simulation outcomes. The outcome of this paper makes up for the lack of knowledge of a surfactant-assisted bitumen recovery process and provides insights for further in-situ bitumen production engineering designs. [ABSTRACT FROM AUTHOR]

A computational study on the host–guest complexes of neutral bis(4-nitrophenyl)squaramide (SQ) and halide anions is reported. In the gas-phase, the calculated interaction and stabilization energies indicates a diminishing intrinsic affinity of SQ for anions from fluoride to iodide. The nature of interactions is investigated using Natural Bond Orbital (NBO), Quantum Theory of Atoms in Molecules (QTAIM) along with Energy Decomposition Analysis-Natural Orbitals for Chemical Valence (EDA-NOCV). While electrostatic interactions account for roughly 60% of the total, EDA-NOCV analysis demonstrated increasing contributions of orbital interactions from SQ ⋯ I - to SQ ⋯ F - complexes. In solution, thermodynamic cycle analyses and Gibbs free energy calculations reveal a propensity towards the formation of SQ ⋯ F - , taking into account the influence of solvation energies on the overall stability. The consistent trend observed in selectivity both in the gas phase and in solution suggests that changes in solvation energy do not significantly impact the stability of complexes. The findings were additionally supported by a significant correlation observed between the computed and experimental formation constants. [ABSTRACT FROM AUTHOR]

When nano-fillers are used to enhance the thermal conductivity of organic phase change materials (PCMs), the naturally formed interface is considered to hinder thermal transport of the composite PCMs. However, the effect of the interface on the thermal properties of surrounding PCM has not been fully studied. In this paper, three composite PCMs (Ery@SiC, Ery@SiO2 and Ery@Si3N4) were prepared by melt-blending method. The local thermal conductivity and reduced Young's modulus (E⋆) of the erythritol at the interface and far away from the interface in the composite PCMs were simultaneously measured by scanning thermal microscopy (SThM). The results revealed significant enhancement in local thermal conductivity of erythritol at the interface and its obvious positive correlation with E⋆. For different composite PCMs, molecular dynamics (MD) simulations suggested that the increase in intrinsic thermal conductivity and E⋆ of erythritol is attributed to the increase in interaction energy between erythritol and nanoparticles, as more erythritol phonon vibrations transform from localized mode to delocalized mode and erythritol has a higher density at the interface. These findings will provide new ideas for the design of PCM for energy storage. [ABSTRACT FROM AUTHOR]

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study shows the exploration of the gas‐sensing capabilities of C6N8 material against toxic gases like phosphine (PH3) and phosphorous trichloride (PCl3). First‐principles study based on M05‐2X/LanL2DZ (d, p) method was performed to investigate the interaction energy (Eint.), frontier molecular orbitals (FMOs), natural bonding orbital (NBO), noncovalent interactions (NCIs), partial density of states (PDOS), molecular electrostatic potential (MEP), and quantum theory of atoms in molecules (QTAIM) analyses. The interaction energy results showed that PCl3@C6N8 (−23.45 kJ/mol) is more stable than PH3@C6N8 (−14.79 kJ/mol). A considerable decrease in the HOMO‐LUMO band gap of C6N8 was observed as a result of its complexation with the analytes. QTAIM and NCI analyses indicated the presence of weak noncovalent interactions between C6N8 and gases (PH3 and PCl3). SAPT0 analysis was performed to quantify the NCIs. MEP maps of complexes revealed the localization of electronic density on C6N8. The little recovery time of complexes (determined at 300 K) showed that C6N8 can serve as a reusable sensing material against PH3 and PCl3. Our results demonstrate that the C6N8 surface is a reliable material for detecting phosphine and phosphorous trichloride gases. [ABSTRACT FROM AUTHOR]

Polymers adsorb onto nanoparticles, NPs, by different mechanisms. Thus, they reduce coagulation, avoid undesired phase separation or clustering, and give rise to hybrid colloids. These find uses in many applications. In cases of noncovalent interactions, polymers adsorb onto nanoparticles, which protrude from their surface; the polymer in excess remains in the medium. In covalent mode, conversely, polymers form permanent links with functional groups facing outward from the NPs' surface. Polymers in contact with the solvent minimize attractive interactions among the NPs. Many contributions stabilize such adducts: the NP–polymer, polymer–polymer, and polymer–solvent interaction modes are the most relevant. Changes in the degrees of freedom of surface-bound polymer portions control the stability of the adducts they form with NPs. Wrapped, free, and protruding polymer parts favor depletion and control the adducts' properties if surface adsorption is undesired. The binding of surfactants onto NPs takes place too, but their stabilizing effect is much less effective than the one due to polymers. The underlying reason for this is that surfactants easily adsorb onto surfaces, but they desorb if the resulting adducts are not properly stabilized. Polymers interact with surfactants, both when the latter are in molecular or associated forms. The interactions occur between polymers and ionic surfactants or amphiphiles associated with vesicular entities. Hybrids obtained in these ways differ each from each other. The mechanisms governing hybrid formation are manifold and span from being purely electrostatic to other modes. The adducts that do form are quite diverse in their sizes, shapes, and features, and depend significantly on composition and mole ratios. Simple approaches clarify the interactions among different particle types that yield hybrids. [ABSTRACT FROM AUTHOR]

Binary liquid systems serve as valuable prototypes for comprehending biologically and chemically relevant properties of hydrogen bonds, revealing both noteworthy patterns and anomalies in their behaviour. Aniline, acetone and their binary mixtures with other liquids are used in various industrial processes, drug design, and as cleaning agents. This study is a molecular dynamics exploration of aniline and acetone binary mixture, over a concentration range of 9 : 1–1 : 9 for each component. The investigation includes employing techniques such as radial distribution function (RDF), coordination number calculation, hydrogen bond statistics, and graph theoretical analysis (GTA) through the NetworkX module in python, cluster analysis, Voronoi entropy calculation, interaction energy calculation and FTIR spectroscopy for all concentrations studied. The results uncover a compelling trend: a decrease in the number of hydrogen bonds as the concentration of acetone increases. Additionally, increased acetone concentration correlates positively with the breakdown of larger and more complex hydrogen‐bonded structures, indicating the formation of small hydrogen‐bond structures. [ABSTRACT FROM AUTHOR]

Environmental friendly biocomposites are urgently needed to mitigate the pollution caused by huge consumption of petroleum-based polymers. Renewable carrageenan and polylactic acid (PLA) natural polymers have the potential to replace petroleum-origin polymers. Nevertheless, the carrageenan and PLA themselves inherit poor tensile strength, hydrophobicity and stability. The aim of this study is to underpin the mechanism of synthesis of carrageenan-PLA biocomposite using van't Hoff plot, 1HNMR and density functional theorem simulation. Strong hydrogen bonding was found at 1.88 Å between O atom (carrageenan) and H atom (PLA) and was validated in 1HNMR shifting at 5.3 ppm corresponding to –OH group from PLA. The interaction established in the biocomposite mixed at 50 °C leads to a stronger tensile strength of 75.37 MPa, higher hydrophobicity and thermal stability with highest activation energy of 45.39 kJ/mol. The biocomposite produced from renewable carrageenan-PLA material would be a future replacement for nondegradable plastic as a food packaging material. [ABSTRACT FROM AUTHOR]

Let Ω ⊂ R 2 and let L ⊂ Ω be a one-dimensional set with finite length L = | L | . We are interested in minimizers of an energy functional that measures the size of a set projected onto itself in all directions: we are thus asking for sets that see themselves as little as possible (suitably interpreted). Obvious minimizers of the functional are subsets of a straight line but this is only possible for L ≤ diam (Ω) . The problem has an equivalent formulation: the expected number of intersections between a random line and L depends only on the length of L (Crofton's formula). We are interested in sets L that minimize the variance of the expected number of intersections. We solve the problem for convex Ω and slightly less than half of all values of L: there, a minimizing set is the union of copies of the boundary and a line segment. [ABSTRACT FROM AUTHOR]

Copyright of Inorganic Chemicals Industry is the property of Editorial Office of Inorganic Chemicals Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Understanding the non-covalent interactions of various molecules with bowl-shaped carbon structures at a quantum-chemistry level is important for the design of new materials. In this work, adsorption of three important diatomic molecules (H2, CO, and HF) on a flat coronene molecule and bowl-shaped PAHs (corannulene, sumanene, and triazasumanene) was theoretically investigated. The considerable increase of the interaction energy (Eint) was found for all molecules inside the curved structures compared to coronene (the increase was up to 2 × ). It was shown that dispersion interactions play the main role in total attraction for H2 and CO molecules. For HF molecules, the importance of induction (Eind) and electrostatics (Eel) for adsorption was revealed. QTAIM and IGM analyses showed the existence of non-covalent interactions (H2, CO) and H-bonding (HF) between the adsorbate molecules and the adsorbents. The obtained results establish the potential use of the studied bowl-shaped carbon structures in gas adsorbent systems.

A deep understanding of the micro mechanism of competitive adsorption of CO2 and CH4 in coal seams is crucial for achieving CO2 displacing methane extraction （CO2-ECBM）. Based on the macromolecular structure model of Dongqu Mine No. 8 coal, a study was conducted on the competitive adsorption of single and dual components of CO2 and CH4. The results indicate that the adsorption capacity of CO2 in single component adsorption is significantly greater than that of CH4, and the total adsorption capacity in dual component competitive adsorption increases with the increase of CO2 mole fraction; the selective adsorption coefficient of CO2 for CH4 in dual component adsorption under different molar ratios is always greater than 1, and the larger the molar fraction of CO2, the smaller the selective adsorption coefficient; the interaction energy significantly increases with the increase of adsorption capacity. The larger electrostatic energy in the CO2 adsorption system promotes the adsorption of CO2 by coal macromolecules. Therefore, the interaction energy of different molar ratio systems increases significantly with the increase of CO2 mole fraction; the adsorption potential of CO2 in single component adsorption is greater than that of CH4, while the adsorption potential of CO2 in dual component competitive adsorption increases with the increase of CO2 molar ratio, while the adsorption potential of CH4 decreases with the increase of CO2 molar ratio. This result is consistent with the results of adsorption selectivity analysis.

Studying how polycyclic aromatic hydrocarbons transform into soot particles provides insights into factors affecting their formation, composition, and size distribution. Understanding the growth mechanisms of soot from PAHs is crucial for combustion processes and energy efficiency, addressing environmental, health, and energy challenges linked to soot emissions and air pollution. This research aimed to deepen our understanding of these mechanisms by investigating them through molecular dynamics simulations. It used naphthalene as a representative polycyclic aromatic hydrocarbon. The study explored the effect of parameters like hydrogen atomic percentage and heat flux on properties, such as interaction energy, center of mass size, and soot mass size. Results show that increasing hydrogen atomic percentage from 5 % to 25 % increases the interaction energy from −0.15 to −0.12 kcal/mol. At the same time, it reduces the center of mass size from 92.31 to 88.27 Å and the soot mass size from 30.13 to 28.30 Å. Moreover, raising external heat flux from 0.01 to 0.05 W/m2 increases the interaction energy from −0.1 to −0.08 kcal/mol, but increases the center of mass size from 88.49 to 90.18 Å and soot mass size from 28.33 to 30.30 Å after 10 ns.

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Shale oil in China is widely distributed and has enormous resource potential. The pores of shale are at the nanoscale, and traditional research methods encounter difficulty in accurately describing the fluid flow mechanism, which has become a bottleneck restricting the industrial development of shale oil in China. To clarify the distribution and migration laws of fluid microstructure in shale nanopores, we constructed a heterogeneous inorganic composite shale model and explored the fluid behavior in different regions of heterogeneous surfaces. The results revealed the adsorption capacity for alkanes in the quartz region was stronger than that in the illite region. When the aperture was small, solid–liquid interactions dominated; as the aperture increased, the bulk fluid achieved a more uniform and higher flow rate. Under conditions of small aperture/low temperature/low pressure gradient, the quartz region maintained a negative slip boundary. Illite was more hydrophilic than quartz; when the water content was low, water molecules formed a "liquid film" on the illite surface, and the oil flux percentages in the illite and quartz regions were 87% and 99%, respectively. At 50% water content, the adsorbed water in the illite region reached saturation, the quartz region remained unsaturated, and the difference in the oil flux percentage of the two regions decreased. At 70% water content, the adsorbed water in the two regions reached a fully saturated state, and a layered structure of "water–two-phase region–water" was formed in the heterogeneous nanopore. This study is of great significance for understanding the occurrence characteristics and flow mechanism of shale oil within inorganic nanopores. [ABSTRACT FROM AUTHOR]

Three cocrystals of acridine with 2,7-dihydroxynaphthalene (Ia and Ib) in two different polymorphs and 1,5-dihydroxynaphthalene (II) have been synthesized and characterized by single crystal X-ray diffraction method. Two polymorphs of acridine, 2,7-dihydroxynaphthalene cocrystal crystallizes in same space group with different unit-cell parameters. In (Ia) the O–H group form a syn-anti conformation whereas in (Ib) the O–H group form an anti-anti conformation leads to the polymorphic structure of acridine, 2,7-dihydroxynaphthalene. This study reveals that the influence of π⋯π and C–H⋯π interactions in the formation of one-, two-, and three-dimensional supramolecular frameworks when the classical hydrogen bonds such as O–H⋯N and C–H⋯O are limited to discrete motifs. The acridine molecules form continuous π⋯π stacking in the crystal structure of (Ia) and discrete π⋯π stacking in the crystal structure of (Ib) and (II). The conformational flexibility of the substituted hydroxy group has an influence in the supramolecular frameworks of the three-dimensional crystal structure. The intermolecular interaction energy calculation between the molecular pairs has been carried out to study the strength of the interaction and its dependence on the geometrical parameters. [ABSTRACT FROM AUTHOR]

Interactions between proteins are vital in almost all biological processes. The characterization of protein–protein interactions helps us understand the mechanistic basis of biological processes, thereby enabling the manipulation of proteins for biotechnological and clinical purposes. The interface residues of a protein–protein complex are assumed to have the following two properties: (a) they always interact with a residue of a partner protein, which forms the basis for distance‐based interface residue identification methods, and (b) they are solvent‐exposed in the isolated form of the protein and become buried in the complex form, which forms the basis for Accessible Surface Area (ASA)‐based methods. The study interrogates this popular assumption by recognizing interface residues in protein–protein complexes through these two methods. The results show that a few residues are identified uniquely by each method, and the extent of conservation, propensities, and their contribution to the stability of protein–protein interaction varies substantially between these residues. The case study analyses showed that interface residues, unique to distance, participate in crucial interactions that hold the proteins together, whereas the interface residues unique to the ASA method have a potential role in the recognition, dynamics, and specificity of the complex and can also be a hotspot. Overall, the study recommends applying both distance and ASA methods so that some interface residues missed by either method but crucial to the stability, recognition, dynamics, and function of protein–protein complexes are identified in a complementary manner. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) nanochannels with confined spacing and tunable microenvironment exhibit broad application prospects in molecule‐scale processes. However, mass transport behaviors in nanochannels have yet been clearly elucidated, due to the complex physical and chemical structures of nanochannels. Herein, a series of vertically‐aligned nanochannels with tunable chemistry were fabricated by embedding graphene‐based lamellar membranes into epoxy matrix. In this way, 2 mm‐length robust nanochannels can maintain the molecular transport configuration throughout the membrane without the disturbance from entrance and cross‐layer domains. Based on these platforms, it is demonstrated that molecule–channel and molecule–molecule interactions codetermine molecular transport efficiency by controlling molecular configuration and transfer friction. Significantly, matched interaction energies permit fast transport with methanol permeance of over 26.1 L m−2 h−1 bar−1, which outperforms most reported long‐range nanochannels, while mismatched interaction energies fail to do so. In addition, the vertically‐aligned nanochannels membranes hold exceptional stability because of the mechanical protection of epoxy. [ABSTRACT FROM AUTHOR]

In a traditional water-based dyeing system, large amounts of salts and water are consumed. However, a non-aqueous media dyeing system achieves salt-free and less-water dyeing. In a non-aqueous media dyeing system, a small amount of water is used, which may affect the aggregation morphology of the dyes. The molecular dynamics of reactive dyes on the surface of cotton fibers were investigated. The results showed that the color depth of dyed cotton fabric did not change much when the dosage of salt was below 5.2% o.w.f. However, continuing to increase the amount of salt could influence the dyeing level of dyed fabric. The diffusion coefficient of dye was 0.3044 × 10−5 cm−2/s when there was no salt in dyeing system. But it was decreased by 14.03% and 16.62% when the salt concentration was increased from zero to 5.2% and 13% o.w.f., respectively. When the concentration of sodium sulfate was zero, the dye molecules in the solution displayed in the form of unimolecular molecules and dimers. However, reactive dyes mainly existed in the form of trimers and polymers when the concentration of sodium sulfate was above 5.2%. When there was no salt in the less-water dyeing system, the van der Waal energy between fiber and dye was 131.29 kJ/mol, but it was increased to 382.92 kJ/mol when the dosage of sodium sulfate was 5.2%. Therefore, with the increase of sodium sulfate dosage, the color depth of the dyed fabric changed little, but the level of dyeing property became poorer. [ABSTRACT FROM AUTHOR]

Copyright of Chemical Engineering (China) / Huaxue Gongcheng is the property of Hualu Engineering Science & Technology Co Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the past few decades, the removal of organic solvents from different substances, especially through the use of nanostructured materials, has been crucial in various industries, including improvement of innovative and adaptable nano adsorbents. Computational approaches are widely recognized as powerful tools for searching molecular systems at atomic level and investigating the characteristics of their interactions. This study utilized the dispersion-corrected DFT approach to gain a detailed comprehension of how CH2O molecules interact with both Pd-doped and pristine ZnO nanotubes (ZnONTs) during the adsorption process. The aim was to achieve a comprehensive comprehension of the adsorption behavior. To accomplish this, an extensive examination of the active sites and optimized geometrical characteristics of interacting systems was conducted. To assess adsorption capacity of Pd-ZnO nanotube and pristine ZnO nanotube for CH2O, binding characteristics of the interacting species have been assessed. This evaluation included analyzing the interaction energy (Eint), charge transfer, electronic properties, and ELF analysis. Moreover, Pd-doping greatly enhances the adsorption strength of ZnONTs, thereby imparting them with superior capability for CH2O adsorption. The significant adsorption strength of CH2O by the sensor under consideration raises the prospect of utilizing these nanotubes as highly effective sensor materials for CH2O detection, which is a matter of great interest. The results of our study provide a foundation for designing innovative and energy-efficient nanosensors that can serve as cost-effective solutions for detecting contaminants in wastewater.

The threshold values of CO2 gas stripped off membranous residual oil from the pore walls are not clear under different temperatures, pressures and wettability conditions. The extent to which temperature, pressure and wettability influence CO2 flooding for enhancing the recovery of residual oil in membranous formations also remains uncertain. Therefore, further quantitative characterization is entailed. In this study, the molecular dynamics method was employed to explore CO2 flooding under different temperatures, pressures and wettability conditions, aiming to enhance the production of membranous residual oil. The results reveal that the interaction energy between CO2, decane molecules and pore walls exhibits a decrease with increasing temperature and an increase with increasing pressure, respectively, in distinct wettability scenarios. When the temperature was at or below 363 K and the pressure was not lower than 40 MPa, CO2 gas could detach the membranous residual oil from the pore walls in the water-wet systems. When the temperature was equal to 363 K and the pressure remained under 40 MPa, or the temperature surpassed 363 K, CO2 gas failed to detach the membranous residual oil from the pore walls in the water-wet systems. For the mixed-wet and oil-wet systems, CO2 molecules could not detach the membranous residual oil from the pore walls. The hierarchy of influence regarding temperature, pressure and wettability on the competitive adsorption capacity of CO2 and decane molecules on the pore walls emerged as follows: wettability > temperature > pressure. The findings of this study offer valuable insights into the application of CO2 gas flooding for the exploitation of membranous residual oil on pore walls.

To investigate the mechanism underlying the effect of mixed collector (MC) composed of diesel and span-80 on LRC flotation, a combination of experimental and molecular simulation approaches was employed. The flotation results demonstrated that the use of MC yielded superior flotation performance compared to diesel alone. The ratio of diesel to span-80 emerged as a key factor influencing the performance of MC collection. Furthermore, molecular dynamics (MD) simulations were employed to investigate the adsorption processes of dodecane and MC molecules on the LRC surface in the LRC/dodecane/water and LRC/MC/water systems, respectively. The analysis encompassed microstructure, dynamic properties, interaction energy, and hydrogen bonding. The findings indicated that the presence of span-80 molecules facilitated the direct entry of dodecane molecules in MC into “microscopic cavities,” thereby enhancing the adsorption of MC on the LRC surface. The analysis of interaction energy revealed a stronger interaction between MC molecules and the coal surface, with van der Waals energy playing a major role in the adsorption process. Additionally, span-80 molecules induced hydrogen bonding adsorption on the LRC surface. [ABSTRACT FROM AUTHOR]

To predict the properties of asphalt binder from a molecular point of view, energy index was introduced into asphalt binder performance analysis. The stability of asphalt binder was evaluated using energy as an indicator. The interaction between styrene-butadiene rubber (SBR) and asphalt binder components was analyzed by simulating the energy change of SBR added to the asphalt binder system. Firstly, molecular models of asphalt binder and SBR-modified asphalt binder (SBRA) were established. The structure of the asphalt binder and SBRA systems at room temperature during the pre-structural optimization were analyzed using molecular dynamics simulations and finally based on Materials Studio 8.0. Subsequently, the energies of the output trajectory file at high temperatures (393 K, 413 K, 433 K, 453 K) were analyzed. Finally, the simulation results were verified by macroscopic testing. The results showed that adding SBR did not significantly affect the structure of asphalt binder. However, the addition of SBR improved the energy of asphalt binder at high temperatures. The stability of the SBRA system was optimal at 433 K when the interaction energy between the asphalt binder and SBR was at a maximum. The largest contribution to the interaction energy was van der Waals energy. It is recommended to store SBRA at a temperature of around 433 K during engineering construction. The interaction of the four components of asphalt binder with SBR followed this order: resin-SBR > asphaltene-SBR > aromatic-SBR > saturate-SBR. The higher content of resin and lower content of saturate served to increase the stability between SBR modifier and asphalt binder. The macroscopic test results were consistent with the simulation results, verifying the accuracy of the simulation. Asphalt binder performance can be improved by changing the asphalt binder component content. Analyzing the stability of asphalt binder using energy index provides a new method to study the performance of asphalt binder. [ABSTRACT FROM AUTHOR]

Accurate estimates of intermolecular interaction energy, ΔE, are crucial for modeling the properties of organic electronic materials and many other systems. For a diverse set of 50 dimers comprising up to 50 atoms (Set50-50, with 7 of its members being models of single-stacking junctions), benchmark ΔE data were compiled. They were obtained by the focal-point strategy, which involves computations using the canonical variant of the coupled cluster theory with singles, doubles, and perturbative triples [CCSD(T)] performed while applying a large basis set, along with extrapolations of the respective energy components to the complete basis set (CBS) limit. The resulting ΔE data were used to gauge the performance for the Set50-50 of several density-functional theory (DFT)-based approaches, and of one of the localized variants of the CCSD(T) method. This evaluation revealed that (1) the proposed "silver standard" approach, which employs the localized CCSD(T) method and CBS extrapolations, can be expected to provide accuracy better than two kJ/mol for absolute values of ΔE, and (2) from among the DFT techniques, computationally by far the cheapest approach (termed "ωB97X-3c/vDZP" by its authors) performed remarkably well. These findings are directly applicable in cost-effective yet reliable searches of the potential energy surfaces of noncovalent complexes. [ABSTRACT FROM AUTHOR]

Here, we introduce the use of ANI-ML potentials as a rescoring function in the host–guest interaction in molecular docking. Our results show that the “docking power” of ANI potentials can compete with the current scoring functions at the same level of computational cost. Benchmarking studies on CASF-2016 dataset showed that ANI is ranked in the top 5 scoring functions among the other 34 tested. In particular, the ANI predicted interaction energies when used in conjunction with GOLD-PLP scoring function can boost the top ranked solution to be the closest to the x-ray structure. Rapid and accurate calculation of interaction energies between ligand and protein also enables screening of millions of drug candidates/docking poses. Using a unique protocol in which docking by GOLD-PLP, rescoring by ANI-ML potentials and extensive MD simulations along with end state free energy methods are combined, we have screened FDA approved drugs against the SARS-CoV-2 main protease (Mpro). The top six drug molecules suggested by the consensus of these free energy methods have already been in clinical trials or proposed as potential drug molecules in previous theoretical and experimental studies, approving the validity and the power of accuracy in our screening method. [ABSTRACT FROM AUTHOR]

Cyanobacteriochromes (CBCRs) are linear tetrapyrrole bilin‐binding photoreceptors of cyanobacteria that exhibit high spectral diversity, gaining attention in optogenetics and bioimaging applications. Several engineering studies on CBCRs were attempted, especially for designing near‐infrared (NIR) fluorescent proteins with longer fluorescence wavelengths. However, despite continuous efforts, a key component regulating fluorescence emission property in CBCRs is still poorly understood. As a model system, we focused on red/green CBCR Slr1393g3, from the unicellular cyanobacterium Synechocystis sp. PCC 6803 to engineer Pr to get far‐red light‐emitting property. Energy profiling and pairwise structural comparison of Slr1393g3 variants effectively reveal the mutations that are critical to the fluorescence changes. H497 seems to play a key role in stabilizing the chromophore environment, especially the α3 helix, while H495, T499, and Q502 are potential key residues determining fluorescence emission peak wavelength. We also found that mutations of α2 and α4 helical regions are closely related to the chromophore binding stability and likely affect fluorescence properties. Taken together, our computational analysis suggests that the fluorescence of Slr1393g3 is mainly controlled by the stabilization of the chromophore binding pocket. The predicted key residues potentially regulating the fluorescence emission property of a red/green CBCR will be advantageous for designing improved NIR fluorescent protein when combined with in vitro molecular evolution approaches. [ABSTRACT FROM AUTHOR]

Here, we introduce the use of ANI-ML potentials as a rescoring function in the host–guest interaction in molecular docking. Our results show that the “docking power” of ANI potentials can compete with the current scoring functions at the same level of computational cost. Benchmarking studies on CASF-2016 dataset showed that ANI is ranked in the top 5 scoring functions among the other 34 tested. In particular, the ANI predicted interaction energies when used in conjunction with GOLD-PLP scoring function can boost the top ranked solution to be the closest to the x-ray structure. Rapid and accurate calculation of interaction energies between ligand and protein also enables screening of millions of drug candidates/docking poses. Using a unique protocol in which docking by GOLD-PLP, rescoring by ANI-ML potentials and extensive MD simulations along with end state free energy methods are combined, we have screened FDA approved drugs against the SARS-CoV-2 main protease (Mpro). The top six drug molecules suggested by the consensus of these free energy methods have already been in clinical trials or proposed as potential drug molecules in previous theoretical and experimental studies, approving the validity and the power of accuracy in our screening method. [ABSTRACT FROM AUTHOR]

Bombyx mori chitosan nanoparticles (ChS NPs) were obtained and the kinetic aspects of their size distribution depending on the degree of nonequilibrium of the synthesis by ionotropic gelation using sodium tripofyphosphate (TPP) were studied. The size of ChS NPs was greatly influenced by the ChS concentration, which varied from 0.5 to 10 mg/ml. The size of the NPs increased from 100 to 300 nm when the ChS concentration increased from 0.5 to 10 mg/ml and while maintaining all other parameters of the reaction. An increase in the ChS to-TPP ratio corresponded to a lower cross-linking density and thus ensured slower kinetics for NP formation alongside the formation of large chitosan/TPP aggregates. There was an almost threefold increase in the particle size when the pH of the medium increased from 3.8 to 4.7; thus, the size of ChS NPs depends on the pH of the solution. There was a slight agglomeration of NPs from 363 to 642 nm with an increase in the NP synthesis time from 4 to 24 h. According to calculations, the maximum interaction energy is 50.4 and 69.4 kcal/mol for deprotonated TPP (Ppp); after adiabatic transfer of the proton, the value decreases to 32.9-33.5 kcal/mol. The maximum interaction energy is --12.8 kcal/mol for the initially protonated TPP (H4/p3O10). [ABSTRACT FROM AUTHOR]

Flotation of fine coal particles usually uses oil collectors, but the micromechanisms need to be more defined due to the complex structure and abundant functional groups on the surface of coal bodies [Correction added after first online publication on 16 October 2023: "refined" was changed to "defined" in the first sentence of the article abstract.]. The adsorption spreading behavior and interfacial properties of nonpolar oil drops on flat low‐order coal (LOC) and high‐order coal (HOC) surfaces were investigated in depth using molecular dynamics (MD) simulations, while the effects of different functional groups on LOC surfaces were also considered. The results showed that the contact angle, contact area and interaction energy of oil drops adsorbed on the LOC and HOC surfaces at simulated equilibrium in aqueous environment were 77.68°, 621.49 Å2, −140.94 kcal/mol; 53.98°, 962.14 Å2, and −195.13 kcal/mol, respectively. The smaller the equilibrium contact angle between the oil drops and the surface, the larger the contact area and the larger the absolute value of the interaction energy, the better the spreading effect of the oil drops and the easier the surface is to flotation. Compared with the HOC surface, the oil drops could not displace the water molecules on the LOC surface better and spread poorly on its surface, and the migration rate was higher. This was caused by the abundant functional groups on the surface of LOC. The type of functional group significantly affects the interaction of nonpolar oil drops with hydrophilic surfaces, with the order of adsorption strength being CH3 > COCH3 > OH > COOH. The formation of a dense hydrated film of oil drops on the COOH surface was an important reason for the difficulty of flotation on the LOC surface. MD elucidated the mechanism of action of nonpolar oil collectors on LOC and HOC surfaces, which is a guide for efficient flotation on LOC surfaces. [ABSTRACT FROM AUTHOR]

Three homoleptic Hg(S2CNR2)2, for R = ethyl (1), isobutyl (2), and cyclohexyl (3), compounds apparently exhibit a steric-dependent supramolecular association in their crystals. The small group in 1 allows for dimer formation via covalent Hg–S interactions through an eight-membered {–HgSCS}2 ring as the dithiocarbamato ligands bridge centrosymmetrically related Hg atoms; intradimer Hg···S interactions are noted. By contrast, centrosymmetrically related molecules in 2 are aligned to enable intermolecular Hg···S interactions, but the separations greatly exceed the van der Waals radii. The large group in 3 precludes both dimerization and intermolecular Hg···S interactions. Computational chemistry indicates that the potential region at the Hg atom is highly dependent on the coordination geometry about the Hg atom. Intramolecular (1) and intermolecular (2) spodium bonding (SpB) is demonstrated. Even at separations approaching 0.4 Å beyond the sum of the assumed van der Waals radii, the energy of the stabilization afforded by the structure directs SpB in 2 amounts to approximately 2.5 kcal/mol. A natural bond orbital (NBO) analysis points to the importance of the LP(S) → σ*(Hg–S) charge transfer and to the dominance of the dispersion forces and electron correlation to the SpB in 2. [ABSTRACT FROM AUTHOR]

A molecular model of the interaction between alkaline NaCl solution (Sol) and carbon-supported silver/graphene oxide (Ag/GO/C) composite electrode during oxygen reduction reaction was designed and constructed, and the Molecular dynamics (MD) simulation of the model was carried out. Based on the calculation and analysis of interaction energy (ΔE), diffusion coefficient (D) and radial distribution function (RDF), depending on the type and number of oxygen-containing functional groups of GO, the interaction law between alkaline solution and Ag/GO/C composite electrode was found out, and the interaction mechanism was revealed. The results showed that the interaction force between Sol and Ag/GO/C composite electrodes with 4 different GO structures (GO1, GO2, GO3 and GO4) is mutual attraction at 353 K. The interaction energy between the Sol and the Ag/GO2/C electrode is the highest in numerical terms, and the diffusion capacity of Na+ and Cl– in the Sol is the weakest in the electrode system, indicating that the interaction between the Sol and the Ag/GO2/C electrode prevents the diffusion of solution molecules or ions on the surface of the electrode. The results of RDF showed that O2, Na+ and Cl– in solution within 3.5 Å have no obvious bonding effect with the electrode, while Sol has obvious bonding effect. When the interaction distance is 5–8 Å, O2, Na+, Cl–, Sol in the system and Ag atoms in different composite electrodes all have obvious non-bond interaction, indicating that Sol and the electrode are prone to bond interaction in the short-range region and non-bond interaction in the remote region, while O2, Na+, Cl–, and the electrode are only prone to non-bond interaction in the remote region. In other words, Ag/GO/C composite electrode has bonding and non-bonding effects in the formation of ORR system in alkaline NaCl solution, and it is mainly provided by non-bonding effects. When the number of –O–, –OH, –COOH in GO is 5 : 5 : 2 (GO2), that is, Ag/GO2/C composite electrode is most prone to ORR. This further proved that adding GO to the composite electrode can improve the catalytic performance of the electrode. These results are helpful to provide theoretical support for the research and development of electrodes in electrolytic chlor-alkali industry. [ABSTRACT FROM AUTHOR]