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The mutual penetration of electron densities between two interacting molecules complicates the computation of an accurate electrostatic interaction energy based on a pseudo‐atom representation of electron densities. The numerical exact potential and multipole moment (nEP/MM) method is time‐consuming since it performs a 3D integration to obtain the electrostatic energy at short interaction distances. Nguyen et al. [(2018), Acta Cryst. A74, 524–536] recently reported a fully analytical computation of the electrostatic interaction energy (aEP/MM). This method performs much faster than nEP/MM (up to two orders of magnitude) and remains highly accurate. A new program library, Charger, contains an implementation of the aEP/MM method. Charger has been incorporated into the MoProViewer software. Benchmark tests on a series of small molecules containing only C, H, N and O atoms show the efficiency of Charger in terms of execution time and accuracy. Charger is also powerful in a study of electrostatic symbiosis between a protein and a ligand. It determines reliable protein–ligand interaction energies even when both contain S atoms. It easily estimates the individual contribution of every residue to the total protein–ligand electrostatic binding energy. Glutathione transferase (GST) in complex with a benzophenone ligand was studied due to the availability of both structural and thermodynamic data. The resulting analysis highlights not only the residues that stabilize the ligand but also those that hinder ligand binding from an electrostatic point of view. This offers new perspectives in the search for mutations to improve the interaction between the two partners. A proposed mutation would improve ligand binding to GST by removing an electrostatic obstacle, rather than by the traditional increase in the number of favourable contacts. [ABSTRACT FROM AUTHOR]

Knowing the energetic topology of a surface is important, especially with regard to membrane fouling. In this study, molecular computations were carried out to determine the energetic topology of a polyvinylidene fluoride (PVDF) membrane with different surface wettability and three representative probe molecules (namely argon, carbon dioxide and water) of different sizes and natures. Among the probe molecules, water has the strongest interaction with the PVDF surface, followed by carbon dioxide and then argon. Argon, which only has van der Waals interactions with PVDF, is a good probing molecule to identify crevices and the molecular profile of a surface. Carbon dioxide, which is the largest probing molecule and does not have dipole moment, exhibits similar van der Waals and electrostatic interactions. As for water, the dominant attractive interactions are electrostatics with fluorine atoms of the intrinsically hydrophobic PVDF membrane, but the electrostatic interactions are much stronger for the hydroxyl and carboxyl groups on the hydrophilic PVDF due to strong dipole moment. PVDF only becomes hydrophilic when the interaction energy is approximately doubled when grafted with hydroxyl and carboxyl groups. The energetic heterogeneity and the effect of different probe molecules revealed here are expected to be valuable in guiding membrane modifications to mitigate fouling.

This study focused on the effect of algae on the fouling potential and dynamic fouling variation of foulants in an innovative algal-sludge membrane bioreactor (AS-MBR). Filtration experiments revealed that the soluble extracellular polymeric substance (S-EPS) released by the algal-sludge flocs showed a slower diminishing rate of flux than that released by the sludge flocs. The intermediate blocking and cake filtration models demonstrated the major mechanisms, which implied a reduction in the driving force of pore blocking and fouling layer formation induced by the algal-bacterial S-EPS. Furthermore, the relative flux decrements of loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS) in the AS-MBR were lower than those of the control without algae, indicating a reduction in the fouling potential of the bound EPS (B-EPS) in the algal-sludge flocs compared to the control. This could be attributed to the reduction in the membrane intercepts for LB- and TB-EPS, respectively. Specifically, S-EPS and B-EPS released by algal-sludge flocs had a lower free energy of cohesion (ΔGcoh) than those released by sludge flocs (decreased of 19.14%, 45.93%, and 43.34% for the S-EPS, LB-EPS, and TB-EPS, respectively). Furthermore, these changes could contribute to the decrease in the relative abundance of adsorbed polysaccharide- and protein-like substances in the B-EPS (released by algal-sludge flocs) filtration membrane, leading to the formation of less rough peaks and valleys in the fouling layer in the AS-MBR. Accordingly, the lower fouling propensity and weaker cohesion energy of S-EPS and B-EPS tend to decrease the hydrophobicity and the free energy of the floc surface and further provide less driving force to adhere to the membrane, resulting in significant mitigation of membrane fouling in the AS-MBR. Therefore, the overall fouling behavior caused by S-EPS, B-EPS and flocs should be comprehensively considered to achieve an underlying understanding of the algal effect on membrane fouling control.

The presence of moisture accelerates the aging of oil-paper insulation systems and reduces the insulating performance. In this study, the molecular dynamics method was used to investigate the diffusion behavior of water molecules in palm oil and compared with the diffusion behavior of water molecules in mineral oil. The mineral oil-water mixture model and vegetable oil-water mixture model were established; then, molecular dynamics calculations were performed on the established models from 323 K to 363 K. The free volume, diffusion coefficient, number of hydrogen bonds and interaction energy were analyzed. The results showed that the diffusion of water molecules in the two oils was gradually increased with increasing temperature, but the diffusion capability of water molecules in mineral oil was about 1.5–2 times higher than that in palm oil. In addition, the effect of temperatures on water molecules diffusion was found to be greater in mineral oil. This occurs because hydrogen bonds can be formed between palm oil and water molecules, which enhances the binding energy between palm oil and water molecules; moreover, palm oil provides less free space for diffusion of water molecules compared with mineral oil. Thus limiting the diffusion of water molecules in palm oil. Furthermore, because palm oil has a strong adsorption capacity for water molecules, and the water solubility of palm oil is relatively large, therefore, it is beneficial to increase the breakdown voltage of palm oil. • The diffusion of water molecules in oil gradually increased with increasing temperature. • The hydrogen bonds enhanced the interaction energy between palm oil and water molecules. • The diffusion capacity of water molecules in palm oil is less than that in mineral oil. [ABSTRACT FROM AUTHOR]

An interaction energy model is employed to discern the roles of liquid composition and asphaltene properties on asphaltene stability. The model determines Lifshitz‐van der Waals (LW) and acid‐base (AB) for two asphaltenes of A and B types with different polarities and synthetic oils with different nC7 volume fractions. The results indicate that the liquid loses its solubility with increased nC7 volume fraction, due to the reduction in its electron donor component. Moreover, at the very beginning of nC7 addition, both asphaltenes show a similar resistance against aggregation, due to the similar rates of change in their LW and AB interaction energies. However, at latter stages of nC7 addition, the two asphaltenes tend to have different precipitation propensities, which is consistent with the results of UV‐vis measurements. [ABSTRACT FROM AUTHOR]

In this research, the effect of ZnMoO4 nanoparticles (ZM NPs: A) and multi-wall carbon nanotubes (MWCNT: B) on the tensile strength of the epoxy/polyurethane (EP) matrix was investigated using the response surface methodology (RSM). This model was examined through an experimental procedure, and the results illustrated that the RSM was an appropriate tool for optimizing ε, σy, and σu. In addition, due to the importance of the interaction energy (Eint.) for understanding chemical reactions, the Eint. of the SWCNT-COOH, ZM NPs and SWCNT-COOH/ZM particles with the EP/PU polymers was assessed using the molecular dynamic (MD) simulation. The results revealed that the Eint., values for the EP/PU/ZM, EP/PU/SWCNT-COOH, EP/PU/ZM/SWCNT-COOH nanocomposites were −31.08, −18.18, and −50.33 eV, respectively. Therefore, the Eint. values between EP/PU and ZM/SWCNT-COOH was obviously higher than that of the EP/PU/CNT and EP/PU/ZM specimens. [ABSTRACT FROM AUTHOR]

In this paper, metallocene‐fullerene hybrid complexes, [M(η5‐Cp)(η5‐C60Me5)] (M = Fe2+, Ru2+, Os2+), as well as corresponding classical metallocenes have been studied theoretically at BP86/def2‐SVP and M06L/def2‐SVP levels of theory. With considering these metal complexes as an ABA′ system (B is the central metal ion and A and A′ are related η5‐ligands), the total interaction energies were calculated using common methods, as well as by calculating the interaction energies between the four defined pairs of fragments including A–B, B–A′, A–BA′, and AB–A′. The resulting data clearly showed that in all complexes there is a strong anticoopertivity between two metal‐(η5‐ligand) bonds. In order to understand the origin of difference in values of various calculated interactions in above two types of complexes, the nature of metal–ligand bonds was also studied using energy decomposition analysis‐natural orbital for chemical valence calculations. The results showed that in hybrid complexes, in contrast to metallocenes, the orbital interactions are considerably larger than electrostatic interactions. [ABSTRACT FROM AUTHOR]

The interaction of ionic liquids (ILs) with additives or impurities is crucial for the performance of ILs in technological applications. In order to understand the interaction between these, an insight onto the microscopic arrangement of molecules is needed. As a representative case, 1‐ethyl‐3‐methylimidazolium dicyanamide ([EMIM]+[DCA]−) mixtures are studied with dimethyl sulfoxide (DMSO) and water in bulk phase using molecular dynamics (MD) simulations. Different molar fractions of DMSO and water are studied to elucidate the influence of the molecular solute concentration on the structuring of the ILs. The results indicate that DMSO‐[EMIM]+[DCA] and water‐[EMIM]+[DCA]− mixtures are defined by quite distinct molecular interactions between the species. By increasing the DMSO or water concentration, in the former the solute molecules are repelled from the ions, while in the latter they accumulate closer to the ions. The differences arise from the weakening of the interactions between the ions imposed by the presence of the water molecules whereas DMSO promotes a strengthening of these interactions. Accordingly, this study provides a deep understanding of the IL behavior in combination with neutral solute molecules and allows for a proper selection of IL‐solute combinations in view of specific technological applications. [ABSTRACT FROM AUTHOR]

Copyright of ScienceRise: Pharmaceutical Science is the property of PC TECHNOLOGY CENTER 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.)

Crystal agglomeration is an important factor that can affect the purity and crystal habit of crystalline products. Agglomeration of niacin crystals in its cooling crystallization and its mechanism is investigated using both experimental and molecular dynamics simulation methods. The magnitude of the interaction energy which is mainly contributed by the hydrogen bond and π–π stacking between the (0 1 1) crystal face and (1 1 −1) crystal face that have both the pyridine and carboxyl groups is the main factor determining the extent of agglomeration of niacin crystal. Besides, the interaction energy increases with the crystallization temperature and the supersaturation of the solution, and hence the agglomeration is more severe. The change of solvent species has minimal effect on the agglomeration of crystals. Besides, the agglomeration situation of carbamazepine and acetaminophen that with similar structures to niacin is also verified using molecular dynamics simulations. The findings in this work can be used to predict, control the agglomeration phenomenon, and optimize the crystallization process of niacin and other substances with similar chemical structure. [ABSTRACT FROM AUTHOR]

The object of the present study are BODIPY molecules obtained previously by Piskorz et al. (Dyes Pigm. 178:108322, 2020) for their antimicrobial activity. Structural analysis of the BODIPY dimers is presented in context of the aggregation influence on the photophysical properties. The thorough investigation of the nature of intermolecular interaction in the representative BODIPY dimers is provided together with the decomposition of the interaction energy into the components of well-defined origin according to SAPT procedure. For the model BODIPY systems the careful examination of the interaction nature for the dimer structure based on experimental crystal study as well as fully optimized is given. The tendencies observed in the model dimers are further on investigated for two pairs of BODIPY systems designed for biomedical application. The analyzed molecules are shown to maximize the mutual interaction by the optimization of the stacking dispersion contacts between the aromatic rings of the molecules, therefore producing stable dimers. The estimation of SAPT0 interaction energy components confirms the dominating dispersion character arising from mutual BODIPY core contacts. The influence of the dimerization process on the photophysical properties of the systems studied theoretically depends to the high extend on the dimerization mode and is significant for parallel and antiparallel dispersion-governed dimers. [ABSTRACT FROM AUTHOR]

The engineering of supramolecular architectures needs accurate descriptions of the intermolecular interactions in crystal structures. Tetrathiafulvalene (TTF) is an effective building block used in the construction of promising functional materials. The parallel packing of the neutral TTF–TTF system was studied previously using the high‐level quantum chemical method, advancing it as a valuable model system. The recently developed tight‐binding quantum chemical method GFN2‐xTB and local coupled‐cluster method DLPNO‐CCSD(T) were used to investigate the stacking interactions of TTF and selected derivatives deposited in the Cambridge Structural Database. Using the interaction energy of the TTF–TTF dimer calculated at the CCSD(T)/CBS level as the reference, the accuracies of the two methods are investigated. The energy decomposition analysis within the DLPNO‐CCSD(T) framework reveals the importance of dispersion interaction in the TTF‐related stacking systems. The dispersion interaction density plot vividly shows the magnitude and distribution of the dispersion interaction, providing a revealing insight into the stacking interactions in crystal structures. The results show that the GFN2‐xTB and DLPNO‐CCSD(T) methods could achieve accuracy at an affordable computational cost, which would be valuable in understanding the nature of parallel stacking in supramolecular systems. [ABSTRACT FROM AUTHOR]

The interaction of CO 2 with different deep eutectic solvents (DES) has been studied at the molecular level using density functional theory. Choline chloride and choline bromide were selected as the hydrogen bond acceptors (HBA); urea, ethylene glycol and glycerol were selected as the hydrogen bond donors (HBD). The type and intensity of interactions in DES and that between DES and CO 2 molecules at various interaction sites as well as the quantification of short-range interactions has been studied using Bader's quantum theory of atoms in molecules (QTAIM). The distribution of electrostatic potential (ESP) charges during these interactions has been detailed using the Charges from ESP using a grid (CHELPG) scheme. The non-covalent interactions have been identified using the reduced density gradient (RDG) analysis. Strong van der Waals forces were observed to contribute in the formation of DES. The highest interaction energy of −10.65 kcal/mol was found between the DES2 that comprised of choline chloride and ethylene glycol in the molar ratio of 1:2 and the CO 2. The results of this study show that both HBA and HBD affect the interaction between CO 2 and DES. This study can contribute in designing more specific DES for CO 2 capture and utilization. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Biphasic pretreatment systems extracted up to 73.5% of lignin and 83.0% of xylan. • TsOH/pentanol and AlCl 3 /MTHF systems obtained high-grade lignin samples. • TsOH/pentanol formed the most hydrogen bond networks with lignin and xylan models. • TsOH/pentanol had the highest interaction energy with the lignin (−2460 kJ/mol). • This study provided theoretical insight into the extraction of lignin and xylan. Despite the exceptional performance of recyclable biphasic pretreatment systems (i.e., p -toluenesulfonic acid (TsOH)/pentanol, H 2 SO 4 /butanol, and AlCl 3 /MTHF) in the holistic fractionation of lignocellulosic biomass (LCB), there remains a significant gap in understanding of the intricate mechanisms governing the rapid dissolution of lignin and xylan from LCB. This study conducts comparative analyses using laboratory experiments and computational simulations to gain insights into the mechanism behind removing lignin and xylan in these systems. Under identical pretreatment conditions (140 °C, 45 min), three systems exhibited distinct levels of delignification and xylan removal. TsOH/pentanol showcased the highest levels of both delignification (83.3%) and xylan removal (98.1%), followed by H 2 SO 4 /butanol (77.9% delignification and 83.0% xylan removal), and AlCl 3 /MTHF (73.5% delignification and 97.2% xylan removal). Lignin characterization revealed that TsOH/pentanol and AlCl 3 /MTHF lignin samples boasted well-preserved β-O-4 bonds (42.4/100 Ar, 40.4/100 Ar, respectively), uniform molecular weights, and <1% sugar content. This led to high yields of phenolic monomers (TsOH/pentanol, 33.9%; AlCl 3 /MTHF, 33.7%) after catalytic hydrogenolysis of lignin. Furthermore, mechanistic analyses revealed that the TsOH/pentanol and AlCl 3 /MTHF systems exhibited the most significant interaction energy formation with the lignin model (veratrylglycerol-b-guaiacyl ether) and D-xylan model due to robust hydrogen bonding interactions, yielding energy values of −2460 kJ/mol and −2385 kJ/mol, respectively. These interactions could play pivotal roles in accomplishing notable lignin and xylan extraction. [ABSTRACT FROM AUTHOR]

Diffusion and adsorption are the key to describe the behavior of gas pollutant species in engineered clay barrier. In this study, the diffusion and adsorption properties of multicomponent gases (C 6 H 6 /CH 4 /CO 2) in montmorillonite interlayer were investigated at the molecular level based on molecular dynamics (MD) simulations considering the interaction among gases, water, and montmorillonite. Moisture content has great effect both on diffusion coefficient and adsorption properties of multicomponent gases. The diffusion coefficients firstly increase with increasing water content due to increasing interaction energy between gases and water. When moisture content reaches 10 % or more, the diffusion coefficients decrease slightly or remain unchanged because the interlayer is saturated with water. The interaction force between different gas species accelerates the diffusion of gases and indicates the phenomenon of cross diffusion, which should be considered when studying the transport of multicomponent gases. With moisture content increasing, adsorption capacity of water molecules on montmorillonite increases, while the adsorption capacity of C 6 H 6 /CH 4 /CO 2 decreases. With increasing moisture content, H 2 O molecules first occupy the sorption sites near the surface of montmorillonite as the interaction energy between H 2 O and montmorillonite increases. Gases are sandwiched between water molecule layers when moisture content reaches 10 %. The results found in this study can be used to predict mutual diffusion coefficients of multicomponent gases and to explain the experimental results or engineering issues at molecular scale. [ABSTRACT FROM AUTHOR]

• Newly synthesized oxime barbiturate derivative hydrazone ligand characterized by X-ray crystallography, offering detailed insights into crystal structure, H-atom contacts, and void analysis. • Ligand with -Cl group compared to -CH3 group, revealing higher binding constants and stronger DNA interactions for the -Cl-containing ligand, potentially enhancing biological activity. • Utilizing crystallography, Hirshfeld surface analyses, crystal voids, interaction energy calculations, and energy frameworks, providing a thorough understanding of the ligand's structural and functional properties. • Synthesized compounds exhibit significant inhibitory effects on various cancer cell lines, displaying dose-dependent responses at 24, 48, and 72 h, comparable to etoposide, suggesting their potential as anticancer agents. • Ligands demonstrate promising potential for inducing selective lethality in both cancer and healthy cells, emphasizing their effectiveness as anticancer agents. This study focuses on a newly synthesized compound using 5-acetyl-1,3-dimethyl-barbituric acid and p-chloroisonitrosophenylhydrazine, inspired by a previously synthesized and characterized oxime barbiturate derivative. The compound's biological activity is investigated in comparison to the previously illuminated compound. Additionally, a thorough examination of the The significance of H-atom contacts in determining crystal packing has been validated by Hirshfeld surface representations. Void analysis demonstrates the absence of significant voids, contributing to mechanical stability. Intermolecular interaction energies underscore the dominance of electrostatic and dispersion contributions. Energy frameworks visually convey the magnitude of interaction energies, emphasizing the nearly equal strength of electrostatic and dispersion contributions in crystal stabilization. Furthermore, the study examines the biological activities of the synthesized compounds on various cancer cell lines. Cytotoxicity analyses via MTT assays reveal substantial inhibitory effects of the compounds on cancer cells over 24, 48 and 72 h, displaying dose-dependent responses. Particularly, despite lower cytotoxicity compared to cisplatin, the compounds exhibit comparable activity to etoposide. Cytotoxic selectivity indices (SI) suggest potential selective cytotoxicity against cancer cells. In conclusion, this comprehensive analysis integrates crystallographic insights with biological activity assessments, providing a holistic understanding of the structural and functional properties of the synthesized compounds. The results contribute to advancements in crystal engineering and offer a promising avenue for the development of anticancer agents with selective cytotoxicity. [Display omitted] [ABSTRACT FROM AUTHOR]

• Two new nickel (II) Schiff base complexes were synthesized and characterized. • Complexes 1-2 form monoclinic systems in space group P 2 1 /c. • X-ray crystallography data indicate that complex 1 has a distorted square planar geometry while 2 has distorted octahedral geometry. • Supramolecular chains in 1 through Br...Br and π...π interactions and in 2 via C–Br...π intermolecular interactions have been observed. • For both compounds 1-2 , electrostatic and polarization energies have less influence than dispersion energies. Two new mononuclear Nickel(II) Schiff base complexes [Ni L 2 ] (1) and [Ni L 2 (D M S O) 2 ] (2) where HL is 2,4-dibromo-6-[(E)-{[2-(thiophen-2-yl)ethyl]imino}methyl]phenol, a bidentate Schiff base prepared from the condensation reaction of 2-thiopheneethylamine and 3,5dibromosalicylaldehyde, have been made. Complexes 1-2 are characterized by FTIR, UV-Vis. absorption spectra, TGA analysis (for 2) , and single-crystal X-ray diffraction studies. Complexes 1-2 crystallize in a similar space group P 2 1 /c as a monoclinic system. X-ray crystallography data indicate that complex 1 has a distorted square planar geometry whereas 2 has distorted octahedral geometry. Using the crystallographic data, the Hirshfeld surface (HS) analysis was also carried out to examine the nature and quantitative contribution of all potential non-covalent intermolecular interactions inside the crystal lattice. Supramolecular chains in 1 through Br∙∙∙Br and π∙∙∙π interactions and in 2 via C‒Br∙∙∙π intermolecular interactions have been observed. The interaction energies between molecules within the crystals were computed to get idea about molecular packing stabilization. [Display omitted] [ABSTRACT FROM AUTHOR]

Oil fouling is the crucial issue for the separation of oil-in-water emulsion by membrane technology. The latest research found that the membrane fouling rate was opposite to the widely used theoretical prediction by Derjaguin-Landau-Verwey-Overbeek (DLVO) or extended DLVO (XDLVO) theory. To interpret the contradiction, the molecular dynamics was adopted to explore the molecular behavior of oil and emulsifier (Tween 80) at membrane interface with the assistance of DLVO/XDLVO theory and membrane fouling models. The decreased flux attenuation and fitting of fouling models proved that the existence of Tween 80 effectively alleviated membrane fouling. Conversely, DLVO/XDLVO theory predicted that the membrane fouling should be exacerbated with the increase of Tween 80 concentration in O/W emulsion. This contradiction originated from the different interaction energy between oil/Tween 80 molecules and polyether sulfone (PES) membrane. The favorable free energy of Tween 80 was resulted from the sulfuryl groups in PES and hydrogen bonds (O-H...O) formation further strengthened the interaction. Therefore, Tween 80 could preferentially adsorb on membrane surface and form an isolation layer by demulsification and steric hindrance and resist the aggregation of oil, which effectively alleviated membrane fouling. This study provided a new insight in the interpretation of interaction in O/W emulsion. [Display omitted] • Tween 80 enhanced the stability, homogeneity, stable flux of O/W emulsions. • Interaction energy of Tween-PES was at least 2 times higher than that of oil-PES. • Tween 80 shows favorable free energy and forms O-H...O bonds with sulfuryl groups. • MD interprets the contradiction between DLVO/XDLVO theory and fouling propensity. [ABSTRACT FROM AUTHOR]

• The microporous system containing intramolecular pores, intermolecular pores, and slit pores. • Priority of adsorption of CH 4 and CO 2 in micropores of different scales. • Concentration distribution and adsorption proportion of CH 4 and CO 2 in micropores of different scales. • Comparison of diffusion characteristics of CH 4 and CO 2 in microporous systems. • The isosteric heat and interaction energy of CH 4 and CO 2 in microporous systems. Micropores are the main adsorption sites for gases in coal. The research of the adsorption and diffusion pattern of gases in micropores is important for CO 2 -ECBM engineering and other measures to improve production. In this study, a multiscale microporous system with intramolecular pores, intermolecular pores, and slit pores is proposed. Adsorption and diffusion characteristics of CH 4 and CO 2 in different microporous systems were investigated. The results show that the adsorption of different microporous systems is basically consistent at low pressures (<2 MPa). Upon further increase in pressure, adsorption increases with increasing slit pore size. Gas molecules in coal are preferentially adsorbed in the intramolecular and intermolecular pores, and gas molecules in the slit pores are preferentially adsorbed in the slit pore walls. The increase in gas pressure and slit pore size decreases the proportion of gases adsorbed in the intramolecular and intermolecular pores and also increases the proportion adsorbed in the slit pores. Increase in size of the slit pores and decrease in adsorption will result in an increase in self-diffusion coefficients of gases. The results of self-diffusion coefficients of pores with different scales indicate that slit pores have the largest self-diffusion coefficients, followed by the intermolecular pores, and the smallest for the intramolecular pores. The isosteric heat of gases tends to decrease and then increase with increasing adsorption. The increase of slit pore size will decrease interaction energy. This study gives a reference for adsorption and diffusion mechanisms of gases in microporous systems, as well as a basis for gas injection displacement studies. [ABSTRACT FROM AUTHOR]

The detection of toxic gases (NH 3 and NF 3) in regulating and monitoring air quality in the atmosphere has drawn a lot of attention. Herein, we explored a novel material (C 6 N 8) for the detection of the important but toxic gases (NH 3 and NF 3). We investigated the interactions of the NH 3 and NF 3 with C 6 N 8 through DFT at B3LYP, ωB97XD, and non-DFT M06-2X. Counterpoise interaction energy values (E int. cp.) of NH 3 @C 6 N 8 and NF 3 @C 6 N 8 are −0.45 eV and −3.51 eV (for B3LYP), −0.42 eV and 2.11 eV (for ωB97XD) and −0.44 eV and −3.41eV (for M06-2X), respectively. Complexes having the most stable configurations were then subjected to further analyses including frontier molecular orbitals, H-L gap, and conductivity of complexes. An increase in the H-L gap in complexes (NH 3 @C 6 N 8 and NF 3 @C 6 N 8) is observed. The conductivity of NH 3 @C 6 N 8 and NF 3 @C 6 N 8 decreases as compared to C 6 N 8. A considerable change in dipole moment was seen in C 6 N 8 before and after complex formation. This is because of the shifting of charge between C 6 N 8 and gases (NH 3 and NF 3). CHELPG and NBO charge analysis were used to evaluate the amount of charge transfer between C 6 N 8 and gases. These analyses demonstrate that NH 3 and NF 3 withdraw electron density from C 6 N 8. It was found that NH 3 tends to be physically adsorbed on C 6 N 8 while NF 3 adsorbs chemically on C 6 N 8. NCI and QTAIM analyses were performed to investigate the kind of interactions between the surface (C 6 N 8) and gases (NH 3 and NF 3). Furthermore, the recovery time of NH 3 @C 6 N 8 and NF 3 @C 6 N 8 shows that C 6 N 8 can be a better choice for sensing NH 3 and NF 3 gases. [Display omitted] • C 6 N 8 explored first time as a sensing material for NH 3 and NF 3 gases using density functional theory. • NH 3 tend to physically adsorbed while NF 3 adsorbed chemically on C 6 N 8. • FMO, NCI, MEP, QTAIM, Mulliken and NBO analysis were done to see the kind of interaction between C 6 N 8 and analytes (NH 3 and NF 3). [ABSTRACT FROM AUTHOR]

[Display omitted] • The stability of the SARS virus can be affected by various environmental factors. • effect of initial pressure on the stability of the SARS virus in the presence of water/Ag nanofluid is investigated. • using molecular dynamics (MD) simulation. • initial pressure effectively changes the atomic evolution of the virus-nanofluid system. • SARS virus destruction process with water/silver nanofluid affected from initial pressure ratio, appropriately. The stability of the SARS virus can be affected by various environmental factors, including temperature, humidity, and pressure. In the present research, the effect of initial pressure on the stability of the SARS virus in the presence of water/Ag nanofluid (NF) is investigated using molecular dynamics (MD) simulation. The results revealed that initial pressure effectively changes the atomic evolution of the virus-NF system. Numerically, the diffusion coefficient of modeled samples changes from 32.33 nm2/ns to 9.489 nm2/ns by initial pressure varies from 1 bar to 10 bar. This structural evolution caused interatomic distance and force between virus particle changes. Finally, interaction energy is changed by initial pressure variation, and this parameter varies between −0.44695 kcal/mol to −24.65127 kcal/mol in defined initial conditions. From MD outputs, it was concluded physical stability of the SARS virus in the presence of water/silver NF can be manipulated by initial pressure. So, the SARS virus destruction process with water/silver NF affected from the initial pressure ratio, appropriately. Future directions for this research project may involve exploring the influence of additional environmental factors and utilizing the gained knowledge to develop antiviral materials. This study establishes a foundation for further investigations into the interaction between environmental factors, NFs, and viral infections, with the potential to contribute to the development of effective strategies for combating viral infections and designing innovative antiviral solutions. [ABSTRACT FROM AUTHOR]

Abstract Understanding the interaction of CH4 with kaolinite is significant for researchers in the fields of coalbed CH4 and shale gas. The diffusion behaviors of CH4 in kaolinite with water contents ranging from 0 to 5 wt% have been analyzed by molecular dynamics simulations. The results of the simulations indicate that CH4 molecules can jump between adjacent holes in the kaolinite matrix. CH4 diffusion coefficient was very low (3.28 × 10−9 m2/s) and increased linearly with the increasing of water content. As the water content decreased, the value of radial distribution function first peak between CH4 and oxygen was larger, meaning that with lower water content, the interaction energy between CH4 and oxygen in kaolinite is stronger. The interaction between CH4 and water is linearly positively correlated with water content, in contrast, the interaction energy between kaolinite and water as well as between kaolinite and CH4 decreased linearly with increasing water content. On the other hand, the diffusion of CH4 molecules adsorbed on the surfaces also can be accelerated by the fast diffusion of water molecules in the middle micropore of the kaolinite.

Hydrogen bonding plays an important role in the design of solid-state structures and gels with desirable properties. 1-(4-Hydroxybenzyl)-2-(4-hydroxyphenyl)-5,6-dimethyl-1H-benzimidazole was isolated as the acetone disolvate, C22H20N2O2·2C3H6O. O—H...N hydrogen bonding between benzimidazole molecules results in chains parallel to [010]. One of the acetone solvate molecules participates in O—H...O hydrogen bonding with the benzimidazole derivative. C—H...π interactions are observed in the extended structure. Hirshfeld surface analysis was used to explore the intermolecular interactions and density functional theory was used to estimate the strength of the hydrogen bonds.

In this study, we present results of a detailed topological analysis of electron density (ED) of 145 halogen-bonded complexes formed by various fluorine-, chlorine-, bromine-, and iodine-containing compounds with trimethylphosphine oxide, Me3PO. To characterize the halogen bond (XB) strength, we used the complexation enthalpy, the interatomic distance between oxygen and halogen, as well as the typical set of electron density properties at the bond critical points calculated at B3LYP/jorge-ATZP level of theory. We show for the first time that it is possible to predict the XB strength based on the distance between the minima of ED and molecular electrostatic potential (ESP) along the XB path. The gap between ED and ESP minima exponentially depends on local electronic kinetic energy density at the bond critical point and tends to be a common limiting value for the strongest halogen bond.

Phenibut is an anxiolytic drug approved for medical use in many eastern European states. With the exception of the HCl Salt of Phenibut no crystal structure related research has been conducted on this substance. Herein, the crystal structures of Phenibut and Phenibut·H2O are presented, including crystal packing analysis based on interaction energy calculations. IR spectra are shown alongside powder diffraction data and thermogravimetric analysis to characterize and compare structural as well as thermal properties of the examined Phenibut forms. Single crystal diffraction is used in conjunction with Crystal Explorer based Hirshfeld analysis to carefully identify the bonding interaction properties in each compound. Finally, a case is made regarding stability of the compared crystalline phases based on the conducted structural analyses and the quantification of the molecular interaction energies. [ABSTRACT FROM AUTHOR]

Detailed studies on the stability, interaction, and microstructure of host‐guest complexes in the vacuum of 5‐fluorouracil (5FU) with β‐cyclodextrin (βCD) were performed using B3LYP with the inclusion of Grimme's dispersion correction GD3 term and 6‐31+G(d,p) basis set. Among several studied 1:1 5FU‐βCD complexes, the one placing the keto tautomer of 5FU vertically in the host cavity and forming N‐H···OCD and CO···HOCD hydrogen bonds with hydroxyl groups of the smaller rim of βCD has the highest stability (Eint = −195 kJ/mol). Interestingly, there are no interactions with the inner hydrophobic part of the βCD host cavity. The strength of the intermolecular H‐bonds to the smaller rim of βCD is comparable to those in 5FU‐water and 5FU‐methanol clusters, used as model systems characterizing the noncovalent interactions. Of several studied host‐guest complexes, the inner ones are more stable than the outer systems. Our results reveal that taking dispersion interaction in DFT into account is essential for reliable modeling of the structure, interaction, and stability of 5FU‐βCD complexes. This study is crucial for understanding the interaction of 5FU with βCD in the solid state and additionally suggests the presence of equilibrium between 5FU‐βCD complex and solvated 5FU. [ABSTRACT FROM AUTHOR]

The compatibility between asphalt and nanosilica (nano-SiO2) is critical to determine the performance of nano-SiO2–modified asphalt. However, a comprehensive understanding of the compatibility behavior and mechanism of asphalt components and nano-SiO2 in the modified asphalt is still limited. In this study, the compatibility was revealed through molecular dynamics (MD) simulation. Virgin asphalt, nano-SiO2–modified asphalt, and oxidation aged asphalt models produced with the COMPASS force field; meanwhile, the proposed models were validated by comparisons with reference data. The compatibility of asphalt and nano-SiO2 was analyzed by solubility and the Flory–Huggins parameters and interaction energy. Results show that the solubility parameters decreased with the increase of system temperature while increased with the asphalt's oxidation level increase. Meanwhile, the compatibility of the asphaltene, resin, and aromatic components in asphalt is better than the compatibility with saturates, which may be due to saturates being volatile; however, the compatibility of the nano-SiO2 and saturates is much better than those with asphaltene, resin, and aromatic components. The incorporation of nano-SiO2 alleviates the volatilization of saturates. The present results provide insights into the understanding of the compatibility behavior and mechanism of nano-SiO2 and asphalt components. [ABSTRACT FROM AUTHOR]

With its unique two-dimensional structure and many outstanding features, reduced graphene oxide (rGO) can be used as an ideal electrode material. However, the mechanism of its interaction with the electrolyte solution is still unclear. The molecular model of the interaction between nitrobenzene (PhNO2) and rGO loaded iron (Fe/rGO) in ionic liquid 1-butyl-3-methylimidazole hexafluorophosphate ([BMiM][PF6]) was designed and constructed by using Materials Studio (MS) software, and the molecular dynamics (MD) simulation was performed. This paper discusses the influence of rGO with different oxygen–containing functional groups (–OH, –O–, –COOH) on the interaction, reveals the nature of the interaction, and provides a theoretical basis for the reaction process of reduction of nitrobenzene catalyzed by rGO. The results show that in [BMiM][PF6], the interaction energy between PhNO2–Fe/rGO is negative, indicating that the interaction is mainly characterized by mutual attraction. Among the 7 rGO systems, rGO2 showed the strongest interaction attraction and rGO5 the weakest. The diffusion coefficient of nitrobenzene in rGO5 system is the largest, rGO2 is the smallest. From the analysis of the radial distribution function (RDF), it can be seen that within 3.5 Å, nitrobenzene molecules are prone to bond with Fe atoms on rGO5, while nonbonding outside 3.5 Å is relatively weak. This indicates that Fe/rGO catalyzed PhNO2 system has bonding and nonbonding, and mainly bonding. Around 3.5 Å, the order of RDF peak values is consistent with the diffusion coefficient and opposite of the interaction energy. This indicates that the weaker the interaction between PhNO2 and Fe atoms on rGO, the smaller the binding of nitrobenzene molecules and the easier the diffusion. [ABSTRACT FROM AUTHOR]

Membrane fouling remains one of the most critical drawbacks in membrane filtration processes. Although the effect of various operating parameters—such as flow velocity, concentration, and foulant size—are well-studied, the impact of particle shape is not well understood. To bridge this gap, this study investigated the effect of polystyrene particle sphericity (sphere, peanut and pear) on external membrane fouling, along with the effect of particle charge (unmodified, carboxylated, and aminated). The results indicate that the non-spherical particles produce higher critical fluxes than the spherical particles (i.e., respectively 24% and 13% higher for peanut and pear), which is caused by the looser packing in the cake due to the varied particle orientations. Although higher crossflow velocities diminished the differences in the critical flux values among the particles of different surface charges, the differences among the particle shapes remained distinct. In dead-end filtration, non-spherical particles also produced lower flux declines. The shear-induced diffusion model predicts all five particle types well. The Derjaguin-Landau-Verwey-Overbeek (DLVO) and extended DLVO (XDLVO) models were used to quantify the interaction energies, and the latter agreed with the relative critical flux trends of all of the PS particles. As for the flux decline trends, both the DLVO and XDLVO results are in good agreement.

Contemporary techniques of molecular modeling allow for rational design of several specific classes of artificial proteins. Transmembrane channels are among these classes. A recent successful synthesis of self-assembling, highly symmetrical 12- or 16-helix channels by David Baker’s group prompted us to study interactions between one of these proteins, TMHC6, and low-molecular-weight components of the environment: water molecules and ions. To examine protein stability in a polar environment, molecular dynamics (MD) with classical force fields of the AMBER family was employed. Further characteristics of the chosen interactions were obtained using interaction energy calculations with usage of partially polarizable GFN-FF force field of Spicher and Grimme, symmetry-adapted perturbation theory (SAPT) and atoms in molecules (AIM) approaches for models of residues from the channel entry, crucial for interactions with water molecules and ions. The comparison of the interaction energy values between the gas phase and solvent reaction field gives the quantitative estimation of the strength of the interactions. The energy decomposition via the SAPT method showed that the electrostatics forces play a dominant role in the substructure stabilization. An application of the AIM theory enabled a description of the intermolecular hydrogen bonds and other noncovalent interactions.

Local energy decomposition analysis provides a breakdown of the domain‐based local pair natural orbital CCSD(T) [DLPNO‐CCSD(T)] energy into additive contributions representing the interaction between pairs of user‐defined fragments. Each of these fragment‐pairwise components can be further decomposed into a sum of physically meaningful terms, such as electrostatics, dispersion, and exchange. In this study, the dependence of such energy terms on the basis set size, the approximations used for the two‐electron integrals, and the localization scheme used for the virtual orbitals have been carefully evaluated on the interaction energies of the S66 benchmark set. A comparison with the energy components obtained at the SAPT2 + (3)δMP2 level of Symmetry‐Adapted Perturbation Theory is also provided. [ABSTRACT FROM AUTHOR]

The interaction energy of two molecules system plays a critical role in analyzing the interacting effect in molecular dynamic simulation. Since the limitation of quantum mechanics calculating resources, the interaction energy based on quantum mechanics can not be merged into molecular dynamic simulation for a long time scale. A deep learning framework, deep tensor neural network, is applied to predict the interaction energy of three organic related systems within the quantum mechanics level of accuracy. The geometric structure and atomic types of molecular conformation, as the data descriptors, are applied as the network inputs to predict the interaction energy in the system. The neural network is trained with the hierarchically generated conformations data set. The complex tensor hidden layers are simplified and trained in the optimization process. The predicted results of different molecular systems indicate that deep tensor neural network is capable to predict the interaction energy with 1 kcal/mol of the mean absolute error in a relatively short time. The prediction highly improves the efficiency of interaction energy calculation. The whole proposed framework provides new insights to introducing deep learning technology into the interaction energy calculation. [ABSTRACT FROM AUTHOR]

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.

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., (© 2023 Wiley Periodicals LLC.)

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 (M pro ). 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., (© 2024. The Author(s).)

Halogen bond (X‐bond) is a noncovalent interaction between a halogen atom and an electron donor. It is often rationalized by a region of the positive electrostatic potential on the halogen atom, so‐called σ‐hole. The X‐bond strength increases with the atomic number of the halogen involved; thus, for heavier halogens, relativistic effects become of concern. This poses a challenge for the quantum chemical description of X‐bonded complexes. To quantify scalar relativistic effects (SREs) on the interaction energies and σ‐hole properties, we have performed highly accurate coupled‐cluster calculations at the complete basis set limit of several X‐bonded complexes and their halogenated monomers. We found that the SREs are comparable in magnitude to the effect of the basis set. The nonrelativistic calculations typically underestimate the attraction by up to 5% or 23% for brominated and iodinated complexes, respectively. Counterintuitively, the electron densities at the bond critical points are larger for SRE‐free calculations than for the relativistic ones. SREs yield smaller, flatter, and more positive σ‐holes. Finally, we highlight the importance of diffuse functions in the basis sets and provide quantitative arguments for using basis sets with pseudopotentials as an affordable alternative to a more rigorous Douglas‐Kroll‐Hess relativistic theory. [ABSTRACT FROM AUTHOR]

• Substantial increase of acid-base interaction energy with surface temperature • Reduction of Lifshitz-van der Waals interaction energy with surface temperature • Spreading coefficient better interpolates dependency of deposition on temperature • Surface energy-based correlation for prediction of CaSO 4 deposition propensity • Impact of surface temperature on coagulation to precursors While numerous surface energy-based studies have investigated various aspects of CaSO 4 deposition on modified surfaces, the impact of surface temperature though, as a dominant parameter, has not thoroughly been characterized from surface energy perspective. This has led that most previous studies have attained surface energy specifications at ambient temperature for utilization at elevated operating temperatures. The present study examines the impact of surface temperature in the range of 293–368 K, but at a constant bulk temperature less than surface temperature, on surface energy and its sub-components of several metallic surfaces and amorphous carbon-based coatings. Moreover, the influence of surface temperature on the energy of adhesion between CaSO 4 precursors and these surfaces, energy of cohesion between precursors as well as wettability of surfaces in terms of spreading coefficient are also investigated. Results showed that the Lewis acid-base sub-component of surface energy experiences profound changes, at least 3-fold increase, with temperature, while it is a maximum of 1.5-fold decrease for the Lifshitz-van der Waals sub-component. A cumulative correlation based on the spreading coefficient is also proposed to project the propensity of investigated surfaces to CaSO 4 deposition as a function of temperature and is validated using data from the literature. [ABSTRACT FROM AUTHOR]

Abstract In order to realize the macroscopic features of a number of chemically bonded multi-layer dielectric and composite materials, interactions of metal oxide surfaces, polymer surface atoms, and near-surface atoms are very beneficial. The simulation study of polymer-metal oxides interfaces is of great importance in investigating the adhesion and miscibility features of these systems that are inherently challenging to obtain experimentally or for which there is no experimental data, even if some low data exist, they are not reliable. Polycaprolactone (PCL) is biocompatible, biodegradable, non-toxic and hydrophobic polyester that has been used in tissue engineering, such as a bioactive implant. Hence, the molecular dynamics simulations of PCL are carried out to investigate its surface interaction with metal oxides as ZnO, CuO, Fe2O3, NiO and SiO2. The force field of COMPASS is applied to simulations in order to compute interfacial and solubility parameters. Molecular dynamics approach to investigate the interaction and adsorption manner of PCL with metal oxides. Whereas investigations are useful in exploring polymer composites. Much better adhesion is achieved by the calculations between the PCL oligomer and the metal oxides under investigation. The negative values of interaction energy have to be forecasted despite the presence of acid-base or hydrogen-bonding interactions.

The data in this article provide information on spectroscopic and theoretical data for p-chlorocalix[4]arene when combined with selected drugs, such as paracetamol, ibuprofen, and cetirizine. The present spectroscopic data are generated from Fourier Transform Infrared (FTIR), Nuclear Magnetic Resonance (1H NMR and 13C NMR), and Ultraviolet-Visible spectroscopy (UV-Vis) as the key tools for molecular characterization. The measurement of the optimization energy, interaction energy, and the band gap energy between the molecules was calculated by Gaussian 09 software. It is interesting to note that of the three titled drugs identified, p-chlorocalix[4]arene showed the highest interaction energy with paracetamol, followed by ibuprofen and cetirizine.

An understanding of the driving forces resulting in crystallization vs organogel formation is essential to the development of modern soft materials. In the molecular structure of the title compound, methyl 10-[4-(4-hydroxyphenyl)phenoxy]decanoate (MBO10Me), C23H30O4, the aromatic rings of the biphenyl group are canted by 6.6 (2)° and the long-chain ester group has an extended conformation. In the crystal, molecules are linked by O—H...O hydrogen bonds, forming chains along [10\overline{3}]. The chains are linked by C—H...O hydrogen bonds, forming layers parallel to the ac plane. The layers are linked by C—H...π interactions, forming a three-dimensional supramolecular structure. The extended structure exhibits a lamellar sheet arrangement of molecules stacking along the b-axis direction. Each molecule has six nearest neighbors and the seven-molecule bundles stack to form a columnar superstructure. Interaction energies within the bundles are dominated by dispersion forces, whereas intercolumnar interactions have a greater electrostatic component.

The local energy decomposition (LED) analysis allows for a decomposition of the accurate domain-based local pair natural orbital CCSD(T) [DLPNO-CCSD(T)] energy into physically meaningful contributions including geometric and electronic preparation, electrostatic interaction, interfragment exchange, dynamic charge polarization, and London dispersion terms. Herein, this technique is employed in the study of hydrogen-bonding interactions in a series of conformers of water and hydrogen fluoride dimers. Initially, DLPNO-CCSD(T) dissociation energies for the most stable conformers are computed and compared with available experimental data. Afterwards, the decay of the LED terms with the intermolecular distance (r) is discussed and results are compared with the ones obtained from the popular symmetry adapted perturbation theory (SAPT). It is found that, as expected, electrostatic contributions slowly decay for increasing r and dominate the interaction energies in the long range. London dispersion contributions decay as expected, as r−6. They significantly affect the depths of the potential wells. The interfragment exchange provides a further stabilizing contribution that decays exponentially with the intermolecular distance. This information is used to rationalize the trend of stability of various conformers of the water and hydrogen fluoride dimers.

This work deals with the drug design, synthesis, crystallization, and the interpretation of 4,6‐dimethyl‐2‐(3‐(p‐tolyloxy)propoxy)nicotinonitrile fleximer (1). The structural analysis of compound (1) is performed through single‐crystal X‐ray diffraction and Hirshfeld surface analysis. This fleximer in silico binding affinity is studied to analyze the role of flexibility in noncovalent binding affinity toward the COX‐2 and mGluR2 receptor. Both pyridine ring and phenyl rings are linked with propylene linker. 4,6‐Dimethyl‐2‐(3‐(p‐tolyloxy)propoxy)nicotinonitrile has Z = 4 in the crystal packing and is stabilized by intermolecular noncovalent interactions like C─H···N, C─H···O, C─H···л, л···л, loan pair···л interactions, etc. [ABSTRACT FROM AUTHOR]

In this paper we consider some physical phenomena in the vicinity of a conducting plate in a non-minimal Lorentz-violating scenario in 3 + 1 dimensions. We consider a model where the dynamics of the abelian gauge field is given by the standard Maxwell Lagrangian added by a Lorentz symmetry breaking term with the presence of higher order derivatives in the gauge field. The Lorentz symmetry breaking is due to the presence of a single background vector dλ and we perform the calculations perturbatively up to first order in dλ. We obtain the propagator for the gauge field in the presence of a mirror and the interaction force between the mirror and a point-like electric charge, as well as the interaction force between the mirror and an electric dipole. We show that, on the contrary to what happens in a minimal Lorentz-violating scenario with one single background field (L.H.C. Borges, F.A. Barone, Eur. Phys. J. C 693, 77, 2017), the image method is not valid in the model that we consider in this paper. As a consequence, the symmetry of spatial reflection on the mirror is broken. We also investigate the emergence of a torque in a system composed by a mirror and a point-like electric charge, placed at a fixed distance apart each other. The results obtained in this work have no counterpart in the Maxwell electrodynamics and were not verified in any Lorentz-violating scenario previously. [ABSTRACT FROM AUTHOR]

The interaction energy of the ozone molecule with atoms of noble gases (Ar and He) is analyzed. The coupled cluster methods CCSD(T) and CCSD(T)-F12 with orbital basis sets including electrons from diffuse orbitals (aug-cc-pVXZ for X = D, T, Q, 5, ... CBS) have been used. The geometrical configurations corresponding to the structures with global minima are established. The full three-dimensional grids of the interaction potentials with more than 4800(5300) points have been fitted for the O3–Ar(He) complexes with root-mean-square values of 0.421(0.567) cm–1. The interaction energy was additionally calculated for the O3–He complex with one internal coordinate r1 of ozone stretched to Δr1 = 0.2 and 0.4a0. [ABSTRACT FROM AUTHOR]

The structure, energetics and vibrational spectra of xylofuranose–(H2O)n where n = 2 to 10 cluster have been investigated by using Moller–Plesset second-order perturbation theory (MP) with aug-cc-pvdz as a basis set. Complete basis set limit for the xylofuranose–water clusters were calculate at MP2 level of theory. The incoming water molecule prefers the water–water interaction over the xylose–water interaction. The structural analysis shows that the average water–water distances are observed to be of similar. The calculated O–H stretching frequency is seen to blue shift in all except di-, penta- and hepta-hydrated clusters. In these clusters, the O–H frequency red shifts from isolated xylofuranose molecule. Because the OH group in these clusters is taking part either in intermolecular hydrogen bonding with water molecule or in intramolecular H-bonding with other OH groups present in xylose ring. [ABSTRACT FROM AUTHOR]

This publication was inspired by the study of chaining in dipolar systems. Two adjacent particles form a chain is usually decided by energy or distance criterion. This prompted the author to investigate the frequency of interaction energy between nearby chain-forming particles in the dipolar system. So what is the frequency of the two lowest energies. Does have raison d'etre of the energy-based chaining criterion? Because if so, in the frequency chart qualitative change should have see at 70-75%, compared to the lowest possible energy. No such qualitative change was observed in the computer simulations. Monte Carlo simulations were performed at many densities and dipole moments in a dipolar hard sphere system. The simulation results were theoretically interpreted using the Boltzmann distribution The theoretical relationship was generalized to a wide range of density and dipole moments by fitting three suitable parameters. The fitting was necessary due to the compressive effect of density. [ABSTRACT FROM AUTHOR]