Search

Poly(eutectic) elastomers, as an emerging category of flexible electronic materials, have garnered growing interest for their cost-effectiveness, non-volatility, and biocompatibility. Nonetheless, they encounter challenges including limited functionalities, sensitivity, durability, and mechanical properties. This study involved synthesizing various MXene-doped poly(eutectic) elastomers using robust acrylamide and soft acrylic acid as organic monomers, minor MXene nanosheets as inorganic fillers and physical crosslinkers, and a rapid in-situ photopolymerization method within 2 min. Owing to the synergistic effect of thermodynamic self-assembly, high-density hydrogen bonding, and cation-dipole interactions in the matrix networks, the resulting non-covalently crosslinked elastomers exhibited remarkable mechanical strength (up to ∼ 16.2 MPa) and impressive tensile properties (nearly 700 %), along with rapid electrical self-healing (within 0.046 s) and the ability to withstand loads up to 2500 times their weight following self-healing without fracturing. Notably, these elastomers also demonstrated excellent microstrain (1 %–10 %) sensitivity with a gauge factor of 2.02, wide temperature tolerance (−20 °C ∼ 60 °C), outstanding harsh temperature durability (−20 °C) exceeding 22,000 cycles, and antibacterial properties. Furthermore, these elastomers-assembled strain sensors displayed real-time and rapid response in human motion detection and wireless signal transmission, presenting a promising approach for designing functionally integrated elastomeric materials. [Display omitted] • A novel MXene-doped poly(eutectic) conductive elastomers are facilely fabricated. • Tunable mechanical properties by adjusting ratios of soft monomer, hard monomer and physical crosslinker. • Dynamic non-covalent interactions confer rapid electrical self-healing (<46 m s). • Over 22,000 cycles durability in harsh temperatures (−20 °C). • Real-time response to strain, human motion and wireless signal transmission. [ABSTRACT FROM AUTHOR]

This study computationally investigates the properties and competition of complexes formed by the interaction between hypohalous acids (HOX, where X = F, Cl, Br, and I) and carbonyl selenide (COSe) at the MP2/aug-cc-pVTZ computational level. Three distinct groups of complexes were obtained. The first group, consisting of complexes with a cyclic structure (HB-TB), exhibited the highest stability. remaining two groups formed less stable linear structures with different characteristics (ChB and XB). In the first group, the electronegativity of the halogen atom significantly influenced the stability of the complexes. Conversely, the stability of complexes in groups II and III was primarily determined by the acid and base strengths of the interacting monomers. To comprehensively evaluate the obtained results, various analyses were employed, including Molecular electrostatic potential (MEP), geometry Optimization, Spectroscopic, Interaction energy (SE), Natural bond orbital (NBO) analysis, Atoms in molecules (AIM) analysis, Non-covalent interaction (NCI) index, Energy decomposition analysis (EDA), and Electron density difference(EDD) analysis. [ABSTRACT FROM AUTHOR]

Light‐emitting organic small molecules require high internal and external quantum efficiencies with excellent radiative characteristics for their potential application in next‐generation optoelectronics. Nonetheless, achieving high efficiency in solid states remains a formidable challenge, primarily owing to the non‐radiative processes. Therefore, conformational modulation in solid states is pivotal in influencing emission properties to mitigate non‐radiative decay. Notably, modifying intra‐ and intermolecular non‐covalent interactions (NCIs) is a promising strategy that can simultaneously realize rigidity and stabilization of flexible single bonds, thus suppressing reorganization energy associated with non‐radiative decay. Consequently, considerable emission enhancement is attainable through adept manipulation of NCIs, corresponding to systems ranging from single molecules to multimolecular networks in solid states. This review systematically summarizes and analyzes the influence of diverse NCIs in efficient light‐emitting organic small molecules. The effects of NCIs on single‐and multimolecular‐systems are discussed, based on the fundamentals of light emission mechanism and the correlation between molecular design strategy and photophysical properties. Additionally, strategic perspectives are provided for the advancement of future light‐emitting organic small molecules. Therefore, this review serves as a comprehensive molecular design library, providing an up‐to‐date overview of molecular design leveraging NCIs for efficient light‐emitting organic small molecules. [ABSTRACT FROM AUTHOR]

In the field of anticancer therapy study it is of great interest to find effective G‐quadruplex ligands which may be of potential use in medical treatment or cancer prevention. Since among the compounds of natural origin, flavonoids have attracted notable attention because of their unique properties and promising therapeutic applications, an interesting question was to identify the flavonoid structural features that could provide effective binding properties toward G‐quadruplex. By using electrospray ionization mass spectrometry, followed by the survival yield method, it has been shown that the flavonoid molecules which contain an available C4=O carbonyl group form more stable adducts with G‐tetrads than the other ones. Molecular docking has shown that C4=O carbonyl group can be a source of hydrogen bonds and/or π‐stacking interactions. Therefore, the flavonoid molecules which contain an available C4=O carbonyl group can be regarded as good binders of G‐quadruplexes. [ABSTRACT FROM AUTHOR]

B3LYP/cc-pVDZ generated the best N-(5-((4-ethylpiperazin-1-yl)methyl)pyridin-2-yl)-5-fluoro-4-(4-fluoro-1-isopropyl-2-methyl-1H-benzo[d] imidazol-6-yl) pyrimidin-2-amine (TA) results. The NBO study shows that the LP (1) N16 to π*(C17-N19) has the highest stabilization energy at 53.86 kcal/mol. Electron localization and delocalization areas are confirmed by wavefunction studies. The Gaussian-16w software establishes thermodynamic properties for a titled compound which is confirmed by various solvents. The frontier molecular orbital studies we confirmed by gas phase have the highest bond gap value which is 4.02 eV. The titled compound nitrogen is the nucleophilic attack (blue color) and oxygen is the electrophilic attack (red color), which is confirmed by MEP study. In non-linear optical (NLO) study water solvent shows the highest dipole moment activity, due to the solvent's interaction the gas phase dipole moment is lower. The docking study showed the greatest binding affinity score of −5.28 kcal/mol. [ABSTRACT FROM AUTHOR]

The investigation into conducting organic polymers and cyanogen halides (COPs-CNX) complexes' optimization at the M06-2X/6-31+G(d) level, alongside subsequent analyses, provides valuable insights into the interaction mechanisms between COPs and CNX molecules. The basis set superposition error (BSSE)–corrected interaction energies emphasize the pronounced strength of electrostatic interaction within polyaniline and cyanogen halides (PANI ES-CNX) complexes. Conversely, poly(3,4-ethylenedioxythiophene) (PEDOT), polypyrrole (PPy), and polythiophene (PTh) exhibit weak interactions with CNX. Natural bond orbital (NBO) analysis confirms strong interactions between CNX and PANI ES through nitrogen sites, while halogen sites mediate interactions between CNX and PEDOT, PPy, and PTh. Charge transfer analysis underscores increased transfer within PANI ES-CNX complexes, indicating a stronger interaction. Topological analysis reveals non-covalent electrostatic interactions between COPs and CNX, notably stronger in PANI ES-CNX complexes. The outcomes position PANI ES as a promising candidate for CNX sensing, particularly in CNBr detection. Furthermore, this study computes the recovery time for COPs-CNX complexes, further contributing to the understanding of their applicability in sensing applications. [ABSTRACT FROM AUTHOR]

Electrochemical decarboxylation of carboxylic acids is considered a sustainable method to improve the quality of pyrolysis oil. In this study, we assess the effect of monovalent alkali cations (of the acetates) on the performance of Pt electrodes in acid decarboxylation and the competing OER, using various electrochemical methods. We reveal a strong cation dependence generally following the trend Li+

[Display omitted] Organic multi-stimulus-responsive materials are widely used in anti-counterfeiting and information encryption due to their unique response characteristics and designability. However, progress in obtaining multi-stimulus-responsive smart materials has been very slow. Herein, a spiropyran derivative is constructed, which shows photochromic, thermochromic and mechanical photochromic properties, and has reversible absorption/luminescence adjustment ability. By introducing non-covalent interactions such as van der Waals force and hydrogen bond, this new molecule is more sensitive to external stimuli and exhibits better photochromic, mechanochromic and thermochromic properties with rapid speed and high contrast. Furthermore, these three stimulus responses can be completely restored to the initial state under white light irradiation. The reversible multiple response characteristics of this molecule make it possible to provide dynamic anti-counterfeiting and advanced information encryption capabilities. To demonstrate its application in advanced information encryption, powders treated with different stimuli are combined with fluorescent dyes to encrypt complex digital information. This work puts forward a new time-resolved encryption strategy, which provides important guidance for the development of time-resolved information security materials. [ABSTRACT FROM AUTHOR]

Context: Organic halides stand as invaluable reagents with diverse applications in synthetic chemistry and various industrial processes. Despite their utility, concerns arise due to their inherent toxicity. Addressing these apprehensions, hydro-dehalogenation has emerged as a promising strategy involving the replacement of halogen atoms with hydrogen atoms to transform toxic organic halides into hydrocarbons. This study delves into the computational exploration of hydro-dehalogenation reactions of benzyl halide, mediated by frustrated Lewis pairs (FLPs), using density functional theory (DFT). The reactions entail the formation of FLP1 or FLP2 in the presence of TMP or lutidine with B(C6F5)3, respectively. This is followed by heterolytic cleavage of dihydrogen and subsequent reaction with benzyl halides. Non-covalent interaction analysis underscores the significance of π–π stacking and CH–π interactions in stabilizing transition states. Additionally, the activation strain model (ASM) dissects activation energies, revealing the substantial impact of strain energy on reaction barriers. Energy decomposition analysis (EDA) offers insights into the contributions of electrostatic, orbital, and dispersion energies to the overall attractive interaction energy. The investigation extends to hydro-dehalogenation reactions of ethyl halides, uncovering distinct mechanisms and activation barriers. This comprehensive analysis illuminates the intricacies of hydro-dehalogenation reactions, providing valuable insights into their mechanisms and paving the way for future studies in this field. Methods: Geometry optimizations were carried out at the M06-2X/def2-SVP level of theory, which was performed using the Gaussian 16 program. Solvent-corrected single-point energies were also calculated using the polarizable continuum model (PCM) at the PCM(chloroform)-M06-2X/def2-TZVP//M06-2X/def2-SVP level of theory. The Gibbs free energy correction was determined from computations performed at the M06-2X/def2-SVP level of theory. Principal interacting orbital (PIO) analysis was conducted using the NBO 6.0 software. The nature of bonding in the respective transition state (TS) structures was analyzed using atoms-in-molecules (AIM) analyses. Additionally, the presence of non-covalent interactions (NCI) was exemplified using Multiwfn software. [ABSTRACT FROM AUTHOR]

Halogen bonding permeates many areas of chemistry. A wide range of halogen-bond donors including neutral, cationic, monovalent, and hypervalent have been developed and studied. In this work we used density functional theory (DFT), natural bond orbital (NBO) theory, and quantum theory of atoms in molecules (QTAIM) to analyze aryl halogen-bond donors that are neutral, cationic, monovalent and hypervalent and in each series we include the halogens Cl, Br, I, and At. Within this diverse set of halogen-bond donors, we have found trends that relate halogen bond length with the van der Waals radii of the halogen and the non-covalent or partial covalency of the halogen bond. We have also developed a model to calculate ΔG of halogen-bond formation by the linear combination of the % p-orbital character on the halogen and energy of the σ-hole on the halogen-bond donor.

Lotus rhizome is an important aquatic vegetable, but the blackening of lotus rhizome epidermis (LRE) seriously affects its appearance and quality, which makes lotus rhizome products unmarketable. In this study, the effects of polyphenols and iron on the LRE color were studied to explore the possible mechanism of LRE blackening. Results indicated that the measurable total phenols contents in the mud treatment (MT) group were significantly reduced, and the total iron contents were significantly increased compared with the bruised treatment group (p < 0.05). The high‐performance liquid chromatography results showed that the main polyphenols in LRE were dopa, gallocatechin, and catechin, as well as a small amount of catechol, epicatechin, proanthocyanidin B2, and proanthocyanidin C1. Moreover, the results of color difference and ultraviolet adsorption spectroscopy showed that there were obviously black or brown‐gray of dopa (525 nm), gallocatechin (504.5 nm), and catechin (550 and 504.5 nm) with FeCl2. The simulated system treatment of LRE further confirmed that the chromaticity effect of dopa and iron in bruised LRE was similar to that of the MT group, whereas 1% (w/w) ascorbic acid, 2% (w/w) EDTA‐2Na, or 3% (w/w) citric acid could solely prohibit the blackening. This suggested that the dopa in LRE and FeCl2 in mud may mainly combine into [2(DOPA‐2H+)+Fe3+]− through non‐covalent interaction, which leads to the blackening of bruised LRE under neutral conditions. These results can guide the storage of lotus rhizomes and improve the development of the lotus rhizome industry. [ABSTRACT FROM AUTHOR]

The theoretical study of the complexes produced from the interactions between hypohalous acids (HOX; X = F, Cl, Br, and I) and acetonitrile (AN) was carried out at the MP2/aug-cc-pVTZ level of theory. Three different conformations were produced, namely, A, B, and C, in which conformations B and C were stabilized by only the N···H HB and the N···X XB interactions, respectively. In contrast, conformation A was stabilized by two O···C TB and H···X HB interactions through a cyclic structure. The characteristics of product complexes were analyzed by various methods such as molecular electrostatic potential (MEP), spectroscopy, binding energy (ΔE0), quantum theory of atoms in molecules (QTAIM), natural bond orbital (NBO), energy decomposition analysis (EDA), electron density differences (EDD), and non-covalent interaction (NCI) index. [ABSTRACT FROM AUTHOR]

A pair of novel polymorphic ionic cocrystals of 3,4‐dicyanotelluradiazole and tetraphenylphosphonium bromide are synthesized and are characterized by single‐crystal XRD. Strong and directional non‐covalent chalcogen bonds (ChB) between Te and Br are analyzed via solid‐state NMR to reveal large and anisotropic J(125Te,79/81Br) coupling tensors, providing unequivocal evidence for non‐Fermi contact contributions across ChBs. Along with large 79/81Br quadrupolar couplings for the Br− anions, these data provide new tools to characterize chalcogen bonds and to differentiate between ChB polymorphs. [ABSTRACT FROM AUTHOR]

Metal–ligand coordinated cross‐linked polymeric composites that can alter the network topology via a dynamic bond‐exchange mechanism have been recognized as very promising candidates to address the shortcomings of conventional cross‐linked composites, such as poor recyclability and self‐healing ability. This has led to much interest in the cross‐linking of elastomers via non‐covalent interactions with suitable metal ions. In this report, we present a simple but efficient approach to ferric ions (Fe3+) assisted crosslinking of carboxylated nitrile rubber (XNBR) in the presence of an aliphatic amine (Et3N). The dynamic coordination reaction via carboxylate functional group of nitrile rubber (XNBR) is employed to fulfill the coordination requirements of the central Fe3+ metal ion. This is confirmed by x‐ray photoelectron spectroscopy and Fourier‐transform infrared spectroscopy. The crucial role of Et3N in partially hindering and regulating the extent of crosslinking is investigated and mechanistically interpreted by swelling, differential scanning calorimetry, and rheological study. The tensile strength of ferric crosslinked XNBR could be enhanced up to four times than that of pure XNBR. Furthermore, the dynamic coordination‐driven network of XNBR offers excellent self‐healing (90% efficiency) and recyclability features (80% efficiency) for a composite of appropriate formulations. [ABSTRACT FROM AUTHOR]

Anthocyanins are colored water-soluble plant pigments. Upon consumption, anthocyanins are quickly absorbed and can penetrate the blood–brain barrier (BBB). Research based on population studies suggests that including anthocyanin-rich sources in the diet lowers the risk of neurodegenerative diseases. The copigmentation caused by copigments is considered an effective way to stabilize anthocyanins against adverse environmental conditions. This is attributed to the covalent and noncovalent interactions between colored forms of anthocyanins (flavylium ions and quinoidal bases) and colorless or pale-yellow organic molecules (copigments). The present work carried out a theoretical study of the copigmentation process between cyanidin and resveratrol (CINRES). We used three levels of density functional theory: M06-2x/6-31g+(d,p) (d3bj); ωB97X-D/6-31+(d,p); APFD/6-31+(d,p), implemented in the Gaussian16W package. In a vacuum, the CINRES was found at a copigmentation distance of 3.54 Å between cyanidin and resveratrol. In water, a binding free energy ∆G was calculated, rendering −3.31, −1.68, and −6.91 kcal/mol, at M06-2x/6-31g+(d,p) (d3bj), ωB97X-D/6-31+(d,p), and APFD/6-31+(d,p) levels of theory, respectively. A time-dependent density functional theory (TD-DFT) was used to calculate the UV spectra of the complexes and then compared to its parent molecules, resulting in a lower energy gap at forming complexes. Excited states' properties were analyzed with the ωB97X-D functional. Finally, Shannon aromaticity indices were calculated and isosurfaces of non-covalent interactions were evaluated. [ABSTRACT FROM AUTHOR]

Abstract Electrochemical decarboxylation of carboxylic acids is considered a sustainable method to improve the quality of pyrolysis oil. In this study, we assess the effect of monovalent alkali cations (of the acetates) on the performance of Pt electrodes in acid decarboxylation and the competing OER, using various electrochemical methods. We reveal a strong cation dependence generally following the trend Li+

Bacterial infections arising from antibiotic-resistant strains represent a formidable global health threat. In the realm of antibacterial therapies, supramolecular hydrogels stand out with unique advantages owing to their adaptable and flexible non-covalent interactions with diverse biomolecules. Their ability to encapsulate a variety of biologically active agents through co-assembly further amplifies their efficacy, endowing these hybrid hydrogels with a spectrum of functionalities within a unified system. Various functionalities encompass self-healing, injectability, tissue adhesion, facile drug loading, controlled release mechanisms, biocompatibility, antibacterial properties, and antioxidative attributes. This review article delves into two categories of supramolecular antibacterial hydrogels: i) those with intrinsic antibacterial attributes and ii) supramolecular co-assembled hybrid hydrogels formed through the integration of hydrogels with an assortment of active antibacterial agents, including various nanomaterials, antibiotics, biologically active compounds derived from natural sources, and antibacterial polymers. The anticipated role of supramolecular co-assembled hybrid hydrogels, coupled with contemporary medical technologies and devices, is paramount in the development of highly effective and secure platforms for antibacterial therapy. Furthermore, review addresses the current challenges in the realm of antibacterial hydrogels while elucidating prospective future advancements in this field.

A theoretical investigation on the cooperativity of a series of binary, ternary, and quaternary complexes interconnected by pnicogen bonds has been conducted using calculations at the M06‐2X/aug‐cc‐pVTZ level of density functional theory. By measuring changes in the molecular electrostatic potential (MESP) at the nucleus of interacting atoms in all of the complexes, it is possible to quantify the substantial reorganization of the electron density triggered by the formation of pnicogen bonds. The positive change in MESP, indicating a loss of electron density from the donor molecule in a dimer, facilitates the acceptance of electron density from a third molecule, resulting in the formation of a ternary complex with a stronger pnicogen bond compared to the one present in the binary complex. Similarly, the acceptor molecule in a dimer with a negative change in MESP showed an enhanced tendency to donate electron density to an electron‐deficient third molecule. The MESP analysis provided valuable insights into the donor/acceptor characteristics of pnicogen bonds within the quaternary complexes. The proposed MESP hypotheses are consistent with the positive cooperativity observed in the pnicogen‐bonded clusters. To quantify the changes in MESP, both at the donor atom (ΔVdonor) and the acceptor atom (ΔVacceptor), for all pnicogen bonds in the cluster, the total change in MESP (ΔΔVn) was measured as ΔΔVn = ∑(ΔVdonor)−∑(ΔVacceptor). Remarkably, ΔΔVn exhibited a strong linear relationship with the sum of the bond energies of the pnicogen bonds in the cluster. This establishes the MESP analysis as a robust approach for understanding the strength and cooperative behavior of pnicogen‐bonded clusters. Additionally, the MESP features provided clear evidence of pnicogen bond formation, further supporting the reliability of this approach. [ABSTRACT FROM AUTHOR]

Due to the unstable chemical properties and poor water solubility of carotenoids, their processing adaptation and oral bioavailability are poor, limiting their application in hydrophilic food systems. Lipid-biomacromolecular compounds can be excellent carriers for carotenoid delivery by taking full advantage of the solubilization of lipids to non-polar nutrients and the water dispersion and gastrointestinal controlled release properties of biomacromolecules. This paper reviewed the research progress of lipid-biomacromolecular compounds as encapsulation and delivery carriers of carotenoids and summarized the material selection and preparation methods for biomacromolecular compounds. By considering the interaction between the two, this paper briefly discussed the effect of these compounds on carotenoid water solubility, stability, and bioavailability, emphasizing their delivery effect on carotenoids. Finally, various challenges and future trends of lipid-biomacromolecular compounds as carotenoid delivery carriers were discussed, providing new insight into efficient loading and delivery of carotenoids. [ABSTRACT FROM AUTHOR]

The dry Maillard reaction method was used to glycosylate rice bran globulin. On this basis, the noncovalent binding of glycosylated rice bran globulin with two polyphenols was studied. The interaction mechanism between them was characterized and analyzed by fluorescence spectroscopy, infrared spectroscopy, differential scanning calorimetry, etc. The results showed that the micromorphology of rice bran globulin was changed after glycosylation, and the anti-digestibility and antioxidant properties were improved. Quercetin and resveratrol could both cause fluorescence quenching of glycosylated proteins, and resveratrol caused a red shift in the emission peak of glycosylated proteins. In this non-covalent binding, hydrogen bonding/van der Waals forces played a major role. Fluorescence fitting data showed that glycosylated proteins could bind both resveratrol and quercetin simultaneously, with binding sites and constants of 0.014 7 and 0.002 23, respectively. The binding ability was lower than that of binding resveratrol or quercetin molecules separately. The particle sizes of glycosylated proteins and glycosylated protein-polyphenol non-covalent complexes were higher than that of rice bran globulin, and the maximum particle size occurred when glycosylated proteins were bound to two polyphenols simultaneously. In addition, the non-covalent binding of glycosylated proteins with two polyphenols could significantly improve the protein’s thermal stability and antioxidant capacity, and this improvement was situated between the glycosylated proteins binding to resveratrol and quercetin molecules alone. [ABSTRACT FROM AUTHOR]

Drug–drug interactions occur when two or more molecules interact, potentially altering their effectiveness and cause adverse effect to human health. Caffeine is known to interact with many other drug molecules. Our study was designed to shed insights on characteristics of non-covalent interaction (NCI) and quantify the prevalence of drug–drug interaction between the caffeine and ascorbic acid molecule in gas phase and solvent phase (water) using Density Functional Theory. It was found that caffeine and ascorbic acid molecules interact with one another through hydrogen bonds (HBs) in various ways which can be deduced from the optimized structures and the resulting calculation of binding energy was observed −14.65 kcal/mol and −11.62 kcal/mol in gas and water phase respectively. The Natural Bond Orbital analysis confirmed that the highest stabilization energy interactions are the same interactions which are found to be the possible hydrogen bonds. The RDG, AIM, LED analyses confirmed the delocalisation and localisation of the electron in the complex. The understanding of the non-covalent interaction between caffeine and ascorbic acid may help to further study the drug effectiveness and drug delivery systems. [ABSTRACT FROM AUTHOR]

Context: The complexes formed as a result of the interactions between cyanophosphine (CP, H2PCN) and hypohalous acid molecules (HOX, X = F, Cl, Br, and I) were studied by employing ab initio computations conducted at the MP2/aug-cc-pVTZ level. Three types of complexes were acquired (I, II, and III) as a result of the (O∙∙∙P) pnicogen bond, the (N∙∙∙H) hydrogen bond, and the (N∙∙∙X) halogen bond interaction, respectively. The results of harmonic vibrational frequency calculations with no imaginary frequencies confirmed the structures as minima. In addition, given the interaction energy of the complexes, hydrogen bond complexes of structure II have the highest stability compared to other structures. In all studied complexes, the strength of the interactions depended on the electronegativity of the halogen atoms. The characteristics and nature of the whole three types of complexes were examined and evaluated with natural bond orbital (NBO), atom in molecules (AIM), molecular electrostatic potential (MEP) maps, non-covalent interaction (NCI) index, and electron density difference (EDD) analyses. Method: The optimization of all complexes and corresponding monomers was conducted through the ab initio method, employing the MP2 level along with the aug/cc-pVTZ basis set for all atoms, except for the iodine (I) atom, for which the aug-cc-pVTZ (PP) basis set was employed. Subsequent frequency calculations were executed to ascertain the minimum energy state of the complexes at the MP2 level and the aug/cc-pVTZ basis set, utilizing Gaussian09 software. The MEP maps of the monomers were generated using the analysis-surface suite (WFA-SAS) software package. To probe the orbital interactions within the studied complexes, NBO analysis was performed employing NBO software. The assessment of bond nature, topological features, and electron density values at critical points for the studied complexes was undertaken using AIMAll software. The NCI index was derived utilizing Multiwfn software, and its three-dimensional representation was rendered using VMD software. [ABSTRACT FROM AUTHOR]

In order to improve the ability of solid zein particles to stabilize Pickering emulsions, octenyl succinic anhydride (OSA)-modified starch was used to modify zein. Zein-OSA starch composite particles were prepared by solvent-antisolvent precipitation method. The interaction between zein and OSA starch and the size and structure of the composite particles were studied, and the effects of the mass ratio of zein to OSA starch on the particle size distribution, storage stability, pH stability and rheological properties of Pickering emulsion stabilized with the composite particles were explored. The results showed that OSA starch could modify zein through non-covalent interactions including electrostatic interaction, hydrogen bonding and hydrophobic interaction, changing the secondary structure of zein and improving its hydrophilicity. The composite particles with zein to OSA starch ratio of 1:3 had the smallest average particle size (163.3 nm) and PDI (0.177), and its contact angle was 87.4°, which indicated that the particles had nearly neutral wettability and were more suitable for stabilizing Pickering emulsions. Meanwhile, Pickering emulsions stabilized by the composite particles had the smallest particle size distribution and the highest storage modulus, loss modulus and apparent viscosity, indicating that OSA starch modification could regulate the interfacial properties of zein composite particles and consequently of Pickering emulsions. The above studies show that the interfacial modification of zein can improve the stability of its solid particles and consequently of Pickering emulsions. This study provides theoretical support for further expanding the comprehensive utilization of zein in emulsion systems.

Chalcogen bonding (ChB) is the non‐covalent interaction occurring between chalcogen atoms as Lewis acid sites and atoms or groups of atoms able to behave as Lewis bases through their lone pair or π electrons. Analogously to its sister halogen bonding, the high directionality of this interaction was implemented for precise structural organizations in the solid state and in solution. Regarding catalysis, ChB is now accepted as a new mode of activation as demonstrated by the increased number of examples in the last five years. In the family of ChB catalysts, those based on tellurium rapidly appeared to overcome their lighter sulfur and selenium counterparts. In this review, we highlight the Lewis acid properties of tellurium‐based derivatives in solution and summarize the start‐of‐the‐art of their applications in catalysis. [ABSTRACT FROM AUTHOR]

Anthocyanins, which are the labile flavonoid pigments widely distributed in many fruits, vegetables, cereal grains, and flowers, are receiving intensive interest for their potential health benefits. Proteins are important food components from abundant sources and present high binding affinity for small dietary compounds, e.g., anthocyanins. Protein-anthocyanin interactions might occur during food processing, ingestion, digestion, and bioutilization, leading to significant changes in the structure and properties of proteins and anthocyanins. Current knowledge of protein-anthocyanin interactions and their contributions to functions and bioactivities of anthocyanin-containing foods were reviewed. Binding characterization of dietary protein-anthocyanins complexes is outlined. Advances in understanding the structure-affinity relationship of dietary protein-anthocyanin interaction are critically discussed. The associated properties of protein-anthocyanin complexes are considered in an evaluation of functional and nutritional values. [ABSTRACT FROM AUTHOR]

[Display omitted] Worm-like micelles are susceptible to heating owing to the fast dynamic exchange of molecules between micelles. Inhibition of such exchange could afford robust worm-like micelles, which is expected to largely improve rheology properties at high temperatures. A cationic surfactant docosyl(trimethyl)azanium chloride (DCTAC) and a strongly hydrophobic organic counterion 3-hydroxy naphthalene-2-carboxylate (SHNC) were used for the worm-like micelles fabrication. The microstructure was characterized using cryogenic transmission electron microscopy and small-angle neutron scattering, and the interactions between DCTAC and SHNC were characterized using nuclear magnetic resonance spectroscopy. Rheometer was employed to measure the rheological properties of the solution. SHNC/DCTAC at the molar ration of 1:2 forms ultra-stable worm-like micelles, whose viscosity remain stable at temperature up to 130 °C. SHNC is found to strongly adsorbs on DCTAC micelle with the orientation on the surface of micelle, keeping the naphthalene backbone entire penetration into the palisade layer while both carboxylic and hydroxyl groups protrude out of the micelle. With temperature increasing, this adsorption further strengthens, resulting in the growth contour length and accompanying the enhancement of rheological properties. One SHNC molecule and two DCTAC molecules are speculated to form a stable complex via multiple interactions including hydrophobic, cationic-π, and π-π interactions, which decreases the dynamic exchange of them between micelles. These findings are helpful to understand surfactant aggregates stability and assist the development of novel stable supramolecular nanostructures. Additionally, the excellent thermal stability of this worm-like micellar fluid makes it a potential high-temperature resistant clean fracturing fluid for deep oil reservoirs. [ABSTRACT FROM AUTHOR]

[Display omitted] Colloidal gold nanoparticles (AuNPs) functionalised with hydrophilic thiols can be used as drug delivery probes, thanks to their small size and hydrophilic character. AuNPs possess unique properties for their use in nanomedicine, especially in cancer treatment, as diagnostics and therapeutic tools. Thiol functionalised AuNPs were synthesised and loaded with methotrexate (MTX). Spectroscopic and morphostructural characterisations evidenced the stability of the colloids upon interaction with MTX. Solid state (GISAXS, GIWAXS, FESEM, TEM, FTIR-ATR, XPS) and dispersed phase (UV–Vis, DLS, ζ-potential, NMR, SAXS) experiments allowed to understand structure-properties correlations. The nanoconjugate was tested in vitro (MTT assays) against two neuroblastoma cell lines: SNJKP and IMR5 with overexpressed n -Myc. Molar drug encapsulation efficiency was optimised to be >70%. A non-covalent interaction between the π system and the carboxylate moiety belonging to MTX and the charged aminic group of one of the thiols was found. The MTX loading slightly decreased the structural order of the system and increased the distance between the AuNPs. Free AuNPs showed no cytotoxicity whereas the AuNPs-MTX nanoconjugate had a more potent effect when compared to free MTX. The active role of AuNPs was evidenced by permeation studies: an improvement on penetration of the drug inside cells was evidenced. [ABSTRACT FROM AUTHOR]

Organic solar cells (OSCs), exhibiting better sensitivity to different light intensities and higher power conversion efficiencies (PCEs) under indoor illumination, have great potential to be simultaneously used for solar energy harvesting and optical communication. However, the poor intrinsic molecular stacking and phase separation in active layers significantly hinder the charge transport and extraction in OSCs for achieving this aim. Here, an effective heterohalogen‐substitution asymmetric additive strategy is proposed to fine‐tune the non‐covalent interaction with nonfullerene molecules and optimize the morphology of active layer, which greatly boosts both the OSC photovoltaic performance with the PCEs of up to 18.30% and 29.52% under AM 1.5G and indoor light illumination respectively, and the ‒3 dB communication bandwidths of 4.11, 3.14, and 3.04 MHz at red, green, and blue (RGB) wavelengths respectively. Of particular note, combining the wavelength division multiplexing and adaptive bit‐loading technologies, the visible light communication system comprised of the RGB light sources and additive‐treated OSCs delivers more remarkable data throughput of 302.7 Mb s−1 and higher harvesting power of 7.38 mW simultaneously, presenting an excellent self‐powered capability for enhanced endurance. This work demonstrates that high‐performance OSCs with excellent energy harvesting and wireless communication capacity can be perfectly achieved by a heterohalogen‐substitution asymmetric additive strategy. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department 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 examined the impact of different concentrations of carbon nanotubes (CNTs) on five nematic hybrid liquid crystals (LCs) based on 5CB. Electro-optical properties of the composite were tested, and the interaction between CNTs and LCs was theoretically analysed by first principles. Experimental results showed the effect of CNTs on electro-optical properties of hybrid LCs depended on the groups contained in monomer LCs. LCs with polar groups at the end increased the dielectric anisotropy of the composite, while the impact of CNTs on hybrid LCs containing non-polar terminal monomers was the opposite. The same variation was reflected in splay elastic constants and clearing points. Meanwhile, dielectric anisotropy, splay elastic constant, and rotational viscosity coefficients all changed with CNTs doping concentrations, reflecting the order of binding stability between representative groups and CNTs, and the variation of threshold voltage and response time reflected the order of binding stability between LC molecules and CNTs, consistent with theoretical calculations. Conductivity tests showed the additive of CNTs increased the conductivity of the composite and revealed the impact of CNTs on threshold voltage. Dielectric tests showed the incorporation of CNTs increased dielectric real and imaginary parts in low-frequency regions and increased relaxation frequency in high-frequency regions. [ABSTRACT FROM AUTHOR]

Clean energy and green solvents have attracted wide attention due to their non-toxic, biodegradable, and recyclable properties. Deep eutectic solvent (DES), as a green solvent, has advantages in the formation of nanocellulose. To reveal the formation mechanism during cellulose nanocrystal (CNC) preparation, different carboxylic acid DESs are compared in the optimal experimental conditions. Experimental observations show that oxalic acid (OA) DESs can fabricate CNCs with higher yield, higher crystalline index than that of citric acid series. Moreover, crystal water molecules in DESs promote the reaction activity of DESs in the CNC formation. To understand the interaction among the DES/cellulose complex, molecular dynamics simulations and quantum chemical calculations were applied to investigate the arrangement of CNCs in the atomic scale. The radial distribution function and intermolecular interactions indicate that the non-covalent intermolecular interactions between DESs and cellulose are strong, which could be further enhanced by the crystal waters in DESs. Reaction pathways during the formation of CNCs were revealed by computational simulations, which show that OA is more prone to react with cellulose in esterification and acidolysis reactions. Both computational and experimental results demonstrate that the OA DESs are more beneficial in the production of CNCs. The synergistic effects of chemical reactions and non-covalent interactions favor the formation of CNCs by DESs. [ABSTRACT FROM AUTHOR]

An in-depth analysis on the cooperativity of intermolecular interactions including hydrogen bonding and π-π stacking in 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) crystal was studied. Two quantities, cooperativity rate and energy, were defined to evaluate the nature and strength of cooperativity in a series of clusters diverging from 1D to 3D prototypes. The origin and mechanism of the cooperative effect were settled to demonstrate that the nature of cooperativity is determined by whether the non-covalent interactions compete or promote with each other, which is manifested by the changing trend of electron transfer. There exists obvious cooperative effect in intra-layer and inter-layer structures as they own the equivalent non-covalent interactions, while anti-cooperative effect is also observed if two interactions correlate with each other. On the whole, in the process of crystal formation, the apparent cooperativity is the check and balance of the two effects, which is capable to support a global interaction among all of molecules and contribute to the stabilization of system. Based on the results, one may get a new insight to understand the relationship between non-covalent interactions and low impact sensitivity.

Anthocyanins are colored water-soluble plant pigments. Upon consumption, anthocyanins are quickly absorbed and can penetrate the blood–brain barrier (BBB). Research based on population studies suggests that including anthocyanin-rich sources in the diet lowers the risk of neurodegenerative diseases. The copigmentation caused by copigments is considered an effective way to stabilize anthocyanins against adverse environmental conditions. This is attributed to the covalent and noncovalent interactions between colored forms of anthocyanins (flavylium ions and quinoidal bases) and colorless or pale-yellow organic molecules (copigments). The present work carried out a theoretical study of the copigmentation process between cyanidin and resveratrol (CINRES). We used three levels of density functional theory: M06-2x/6-31g+(d,p) (d3bj); ωB97X-D/6-31+(d,p); APFD/6-31+(d,p), implemented in the Gaussian16W package. In a vacuum, the CINRES was found at a copigmentation distance of 3.54 Å between cyanidin and resveratrol. In water, a binding free energy ∆G was calculated, rendering −3.31, −1.68, and −6.91 kcal/mol, at M06-2x/6-31g+(d,p) (d3bj), ωB97X-D/6-31+(d,p), and APFD/6-31+(d,p) levels of theory, respectively. A time-dependent density functional theory (TD-DFT) was used to calculate the UV spectra of the complexes and then compared to its parent molecules, resulting in a lower energy gap at forming complexes. Excited states’ properties were analyzed with the ωB97X-D functional. Finally, Shannon aromaticity indices were calculated and isosurfaces of non-covalent interactions were evaluated.

The Schiff base was synthesized using the m-bromosalicylaldehyde and ethylenediamine in 1:1 mole ratio. Using the infrared, UV, fluorescence and 1H-13CNMR spectral analysis the m-bromosalicylaldehyde derivative structure was confirmed. Using DFT study the compound structure was optimized. Local energy decomposition (LED) analysis calculated binding energy is -9.19 kcal/mol. The molecule 5BRSET is a optical material, its wavelength is 512 nm and 784 nm respectively. We used three different solvents to calculate the non-linear optical, HOMO-LUMO and molecular electrostatic potential studies, when compared to other solvent the water is showed good activity. Using topological analysis we confirms the localization and delocalization electrons from the synthesized compound. The non-covalent interaction study confirms the intermolecular and intermolecular hydrogen bondings. The natural bond orbital analysis calculation showed the interactions between and within the molecule. A docking study was done on the molecule, and the results show that 5BRSET interacts well with the crystal structure of hypothetical protein (PDB ID: 2EA9). The molecule is moderate activity, which is confirmed by antimicrobial activity.

The absorption studies on serotonin (STO) and platinum metal clusters were investigated. The STO-Pt3 (gas phase) cluster has the maximum adsorption energy, whereas the water medium has the lowest. The gas phase STO-Pt3 absorption energy is -19.18 kcal/mol, while the water solvent is -11.03. The electrophilicity index of all metal-drug systems is greater, indicating that metal clusters make the serotonin more electrophilic. The cluster's conductivity representation as energy gaps pointed, suggesting it could be a sensor. A more stable gas phase medium has more negative solvation energies than other media types. The metal clusters and molecules interacted substantially in non-covalent interaction studies. Electron localized function (ELF) and localized orbital locator (LOL) experiments proved electron delocalization energies and reduced density gradient (RDG) confirmed non-covalent interactions. Molecular electrostatic potential shows the electrophilic and nucleophilic attractions of STO with Pt3 metal clusters. Frontier molecular orbital (FMO) studies show very low energy gap values.

Polychlorinated dibenzo-p-dioxins (PCDD) are persistent organic pollutants which result as byproducts in industrial or combustion processes and induce toxicity in both wildlife and humans. In this study, all seven PCDD, tetrachlorinated dibenzo-p-dioxins (TCDD), pentachlorinated dibenzo-p-dioxins (P5CDD), hexachlorinated dibenzo-p-dioxins (H6CDD), heptachlorinated dibenzo-p-dioxins (H7CDD), and octachlorinated dibenzo-p-dioxins (OCDD) were studied in interaction with two cyclodextrins, β-CD and γ-CD, resulting in a total of 40 host–guest complexes. The flexibility of the cyclodextrins was given by the number of glucose units, and the placement of the chlorine groups on the dioxins structure accounted for the different complex formed. Various geometries of interaction obtained by guided docking were studied, and the complexation and binding energy were calculated in the frame of MM+ and OPLS force fields. The results show that the recognition of the PCDD pollutants by the CD may be possible through the formation of PCDD:CD inclusion complexes. This recognition is based on the formation of Coulombic interactions between the chlorine atom of the PCDD and the primary and secondary hydroxyl groups of the CD and van der Waals interaction of the CD hydrophobic cavity with PCDD aromatic structures. Both MM+ and OPLS calculus resulted in close values for the complexation and binding energies. Molecular mechanics calculations offer a proper insight into the molecular recognition process between the PCDD compounds and CD molecules, proved by a good description of the C-H···O bonds formed between the guest and host molecules. It was shown for the first time that CD may efficiently trap PCCDs, opening the way for their tremendous potential use in environmental remediation. [ABSTRACT FROM AUTHOR]

The new compound 4-hydroxy-1-[(4-nitrophenyl)sulfonyl]pyrrolidine-2-carboxyllic acid was obtained by the reaction of 4-hydroxyproline with 4-nitrobenzenesulfonyl chloride. The compound was characterized using single crystal X-ray diffraction studies. Spectroscopic methods including NMR, FTIR, ES-MS, and UV were employed for further structural analysis of the synthesized compound. The title compound was found to have crystallized in an orthorhombic crystal system with space group P212121. The S1-N1 bond length of 1.628 (2) Å was a strong indication of the formation of the title compound. The absence of characteristic downfield 1H NMR peak of pyrrolidine ring and the presence of S–N stretching vibration at 857.82 cm−1 on the FTIR are strong indications for the formation of the sulfonamide. The experimental study was complemented with computations at the B3LYP/6-311G + + (d,p) level of theory to gain more understanding of interactions in the compound at the molecular level. Noncovalent interaction, Hirsfeld surface analysis and interaction energy calculations were employed in the analysis of the supramolecular architecture of the compound. Predicted ADMET parameters, awarded suitable bioavailability credentials, while the molecular docking study indicated that the compound enchants promising inhibition prospects against dihydropteroate synthase, DNA topoisomerase, and SARS-CoV-2 spike. Herein we present the solid state structure, noncovalent interaction and spectroscopic analysis of a prospective bioactive compound 4-hydroxy-1-[(4-nitrophenyl)sulphonyl]pyrrolidine-2-carboxyllic acid. [ABSTRACT FROM AUTHOR]

Chiral amines are broadly used compounds in pharmaceutical industry and organic synthesis, and reductive amination reactions have been the most appreciated methods for their syntheses. However, one‐step transfer hydrogenative direct asymmetric reductive amination (THDARA) that could expand the scope, simplify the operation and eliminate the use of additives has been challenging. In this work, based on the Xiao's racemic transfer hydrogenative reductive amination in 2010 and our recent work in novel chiral pyridine ligands, chiral half‐sandwich iridium catalysts were rationally designed and synthesized. Using the optimized catalyst and azeotropic mixture of formic acid and triethylamine as the hydrogen source, a broad range of α‐chiral (hetero)aryl amines, including various polar functional groups and heterocycles, were prepared in generally high yield and enantioselectivity under mild and operationally simple conditions. Density functional theory (DFT) calculation of the catalytically active Ir−H species and the key hydride transfer step supported the chiral pyridine‐induced stereospecific generation of the iridium center, and the enantioselection by taming the highly flexible key transition structure with multiple attractive non‐covalent interactions. This work introduced a type of effective chiral catalysts for simplified approach to medicinally important chiral amines, as well as a rare example of robust enantioselective transition‐metal catalysis. [ABSTRACT FROM AUTHOR]

The excellent mechanical properties of supramolecular gel could adapt to the complex reservoir environment and had broad application prospects in the field of oil and gas drilling and production engineering. In this paper, a supramolecular gel based on hydrophobic association and hydrogen bonding was prepared by micellar copolymerization, which could be used to plug fractures and pores in formations. Supramolecular gel was a gel network system with high performance characteristics formed by selfassembly of non-covalent bond interaction. The rheological properties, mechanical mechanics, temperature resistance and swelling ability of supramolecular gel were studied. The results showed that the supramolecular gel had a dense three-dimensional network structure with open and interconnected pore structures, which could exhibit good rheological properties and strong viscoelastic recovery ability. The mechanical properties of the supramolecular gel were excellent, it had a tensile stress of 0.703 MPa and an elongation at break of 1803%. When the compressive strain was 96%, the compressive stress could reach 14.5 MPa. Supramolecular gel also showed good temperature resistance and swelling properties. At the aging temperature of 135 °C, supramolecular gels still maintained good gel strength, and it only took 12 h to reach the equilibrium swelling ratio of 35.87 in 1% NaCl solution. It was also found that supramolecular gel in low concentration saline (1% NaCl solution) showed relatively faster swelling than high concentration saline (25% NaCl solution). The swelling process of the supramolecular gel was non-Fick diffusion (type II). This indicated that the organic/inorganic permeability network was well formed. Therefore, the diffusion rate of small molecules could be guaranteed to be equal to the relaxation rate of large molecules before and after the phase transition temperature. In addition to the diffusion of water molecules, the swelling process of the supramolecular gel was also affected by the relaxation of gel network and polymer chain segment, the interaction between water molecules and polymer network and the groups of polymer network and other factors. Supramolecular gel particles could be used as plugging materials for drilling fluids, which had excellent ability to plug formation fractures and pores. The plugging ability of the supramolecular gel was up to 6.7 MPa for 0.5 mm fracture width, and 9.6 MPa for porous media with 5 mD permeability. Compared with HT-PPG gel particles commonly used in oil fields, supramolecular gel particles had better plugging ability on fractures and porous media. The development and application of supramolecular gel had far-reaching significance for promoting the functional application of polymer materials in drilling and production engineering. [ABSTRACT FROM AUTHOR]

Ions appear as active components in diverse materials. Here, the bonding energy between mechanically interlocked molecules (MIMs) or their acyclic/cyclic molecular derivatives and i) Cl− and Br− ions and/or ii) Na+ and K+ ions, have been investigated. The chemical environment provided by MIMs is less preferably to recognize ionic species compared to unconstrained interactions that are furnished by acyclic molecules. However, MIMs can be more adequate structures for ionic recognition than cyclic compounds if a chemical arrangement of the bond sites that relevantly support more favorable interactions with ions compared to Pauli repulsive ambient is provided. The hydrogen replacement by electron donor (−NH2) or acceptor (−NO2) groups in MIMs favors the anion/cation recognition due to decreased Pauli repulsion energy and/or more attractive non‐covalent bonds. This study clarifies the chemical environment provided by MIMs to interact with ions and highlights these molecules as relevant structures to realize ionic sensing. [ABSTRACT FROM AUTHOR]

Stabilizing nitrogen pnictogen bond interactions were measured using molecular rotors. Intramolecular C=O⋅⋅⋅N interactions were formed in the bond rotation transition states which lowered the rotational barriers and increased the rates of rotation, as measured by EXSY NMR. The pnictogen interaction energies show a very strong correlation with the positive electrostatic potential on nitrogen, which was consistent with a strong electrostatic component. In contrast, the NBO perturbation and pyramidalization analyses show no correlation, suggesting that the orbital‐orbital component is minor. The strongest C=O⋅⋅⋅N pnictogen interactions were comparable to C=O⋅⋅⋅C=O interactions and were stronger than C=O⋅⋅⋅Ph interactions, when measured using the same N‐phenylimide rotor system. The ability of the nitrogen pnictogen interactions to stabilize transition states and enhance kinetic processes demonstrates their potential in catalysis and reaction design. [ABSTRACT FROM AUTHOR]

The second-order nonlinear optical (NLO) crystal materials with the capability of converting the laser frequency, and modulating the amplitude and phase of the laser, are indispensable in practical applications, such as modern manufacturing, laser medical treatment, and communications, as well as in fundamental research. This article provides a brief review of the atom response theory (ART) of nonlinear optical materials developed on the basis of the partial response functional (PRF) method. ART analysis makes it possible to quantitatively evaluate the contribution of individual constituent atoms and orbitals to the second harmonic generation (SHG) response of a nonlinear optical crystal material based on the first principles density functional theory calculations. Besides, a general group division scheme based on physical performance was developed, which provides the conceptual foundation for determining the functional motifs of the SHG effect. In this review, the latest progress of atom response theory and the related new concepts and insights, such as the role of the conduction band, negative atomic contributions, the role of static dipole moment, the overwhelming contribution of non-covalent groups, linear relationships, etc. are explained and elaborated, and some examples for the design of new materials are also given. [ABSTRACT FROM AUTHOR]

We report experimental 125Te magic-angle spinning solid-state nuclear magnetic resonance (MAS NMR) measurements of the tellurium chemical shift (CS) tensors in three [K(18-crown-6)]+ 3,4-dicyano-1,2,5-telluradiazole-XCN− (X = O, S, Se) salt cocrystals featuring chalcogen bonds. These data are compared to those for pure 3,4-dicyano-1,2,5-telluradiazole (1). A reduction in the span of the 125Te CS tensor is consistently noted in the salt cocrystals compared to pure 1. Isotopically 15N-labelled [K(18-crown-6)]+[1-OC15N]−, which features a chalcogen bond between Te and the cyanate nitrogen atom, is synthesized using KOC15N, and the nitrogen CS tensors are measured for both samples via 15N slow MAS NMR spectroscopy. Possible dynamic disorder of the cyanate ions in KOCN is ruled out. Two crystallographically distinct nitrogen sites are resolved for the salt cocrystal. Upon formation of [K(18-crown-6)]+[1-OC15N]−, the 15N isotropic CS and CS tensor span both decrease relative to the values for pure KOC15N, and the axial symmetry of this tensor is lost. These findings are supplemented with a series of density functional theory calculations of magnetic shielding tensors using cluster models or periodic boundary conditions. Inclusion of spin–orbit relativistic effects in the calculation of tellurium shielding tensors is particularly important in achieving agreement with experiment.

Curcumin is one of the important naturally occurring compounds having several medicinal properties such as: antiviral, antioxidant, antifibrotic, antineoplastic as well as anti-inflammatory. SARS-CoV-2 has emerged as infectious virus, which severely infected a large number of people all over the world. Many efforts have been made to prepare novel antiviral compound, but it is still challenging. Naturally occurring compound, curcumin, can be used as an alternative to antiviral compound against SARS-CoV-2. Its effect against SARS-CoV-2 is already highlighted in the literature. But the quantitative study of its interaction with various precursors of SARS-CoV-2 is not reported till date. This paper reports the interaction of curcumin with angiotensin-converting enzyme2, transmembrane serine protease 2, 3-chymotrypsin-like protease and papain-like protease through molecular docking and quantum chemistry calculations to achieve quantitative understanding of underlying interactions. Here the conformational flexibility of curcumin is also highlighted, which helps it to accommodate in the four different docking sites. The study has been performed using calculations of geometrical parameter, atomic charge, electron density, Laplacian of electron density, dipole moment and the energy gap between highest occupied and lowest unoccupied molecular orbitals. The non- -covalent interaction (NCI) analysis is performed to visualize the weak interaction present in the active sites. Combinedly molecular docking and detailed quantum chemistry calculations revealed that curcumin can be adopted as a potential multiple-target inhibitor against SARS-CoV-2.

The 1:1 cocrystal of 4-nitrophenol (NP) and 2,1,3-benzoselenadiazole (BSA) was successfully synthesized. The X-ray single-crystal diffraction analysis revealed that the structure contained a [Se–N]2 cyclic supramolecular synthon. The synthons were connected into a one-dimensional ribbon by O–H···N hydrogen bonds and N–Se···O chalcogen bonds. Furthermore, adjacent ribbons were stabilized by the π···π stacking interactions between two 2,1,3-benzoselenadiazole molecules, leading to the formation of a two-dimensional network.

As a new type of non‐covalent interaction similar to hydrogen bond, halogen bond has become an important supramolecular tool in crystal engineering, material chemistry, biological science, etc., due to its unique properties. In fact, halogen bond has been confirmed on the effect of molecular assemblies and soft materials, and widely used in various functional soft materials including liquid crystals, gels and polymers. In recent years, halogen bonding has aroused strong interest in inducing molecular assembly into low‐molecular‐weight gels (LMWGs). To the best of our knowledge, there is still a lack of in‐depth review of this field. So, in this paper, the recent progress of LMWGs driven by halogen bonding is reviewed. According to the number of components forming halogen bonded gels, the structural characteristics of halogen bonded supramolecular gels, the relationship between halogen bonding and other non‐covalent interactions, as well as the application fields of halogen bonded gels are introduced, respectively. In addition, the challenges faced by halogenated supramolecular gels at present and their development prospects in future have been proposed. We believe that the halogen bonded gel will have more impressive applications in the next few years, opening exciting new opportunities for the development of soft materials. [ABSTRACT FROM AUTHOR]

The intrinsic ability of clathrate hydrates to encage gaseous molecules is explored. Encapsulation ability depends on the cavity size and the type of guest gaseous species in addition to the physical parameters, temperature and pressure. Here we have reported the structure, stability and nature of interaction in dissimilar guest occupied sH hydrate cavity. Diatomic gas molecules and small polyatomic hydrocarbons are considered as guests. The irregular icosahedron (51268) cavity of sH hydrate is the host. Different thermodynamic parameters for the guest molecules encapsulation were calculated using three different hybrid DFT functionals, B3LYP, M05‐2X, M06, and moreover using dispersion correction (PBE0‐D3). With the consideration of large H‐bonded systems the 6‐31G* and cc‐pVTZ basis sets were used for two set of computations. To disclose the nature of interaction between the host‐guest systems as well as the interaction between the guest molecules inside the host the non‐covalent interaction (NCI) indices and energy decomposition analysis (EDA) were done. Impact of host‐guest and guest‐guest interactions are discussed. [ABSTRACT FROM AUTHOR]

A new coordination polymer of coper (II), [tetra-azido)tris(2-pyridyl)amine)dicopper(II)] (1) has been synthesized by the reaction between copper(II) nitrate hexahydrate, sodium azide and tris(2-pyridyl)amine under solvothermal conditions in aqueous methanol. The structure has been characterized by single-crystal X-ray diffraction. An analysis of Hirschfeld surfaces was examined. Single-crystal results reveals that the structure contains two independent copper(II) centers, both having approximately square pyramidal coordination: in one, two of the basal sites are occupied by bidentate tris-(2-pyridyl)amine and two azido ligands, with a third azido ligand at the apical site, while the other center is coordinated only by azido ligands. All azido ligands bind two copper centers, forming a coordination polymer chain with two types of Cu2N2 rings and one type of Cu4N4 ring, and in which all azido ligands form a bridge between two metal centers in mode µ-1,1. The Hirshfeld analysis revealed an azido··· (pyridyl) interaction in the coordination polymer chain, as well as weak C-H···N interactions, one of which links the chains into sheets. A new dinuclear copper (II) polymer [tetra-azido(tris(2-pyridyl)amine)dicopper(II)] (1) has been synthesized under solvothermal conditions and been characterized by single-crystal X-ray diffraction and Hirshfeld surface analysis. [ABSTRACT FROM AUTHOR]

We performed an investigation on urea interacting with hydroxyapatite (HA). The oxygen atoms on HA are either left alone or added with hydrogen to create hydroxyl to resemble the HA surface. Using B3LYP and 3 different basis sets, it was found that urea was able to interact positively with either hydroxyl or non-hydroxyl surface of HA. The Gaussian 09 and Multiwfn software were employed to conduct the calculations. The most favorable interaction has interaction energy of -1.36 eV, which was obtained with the 2 largest basis sets considered, on the pure hydroxyl surface. From the topology analysis on electron density and the non-covalent interaction analysis, it was found that the main attractions between urea and HA were due to the carbonyl oxygen and hydrogen of urea, and hydrogen, oxygen, and calcium on the HA surface. The bond length of newly bonded atoms ranges from 1.62 to 5.18 Å, whereas the energy gap has range between 0.46 to 1.14 eV. All the analysis performed in this study agreed with the results obtained in the formation of favorable interactions and complement previous experimental results that HA can bond with urea molecule. [ABSTRACT FROM AUTHOR]