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Reservoir souring is a widespread phenomenon in reservoirs undergoing seawater injection. Sulfate in the injected seawater promotes the growth of sulfate-reducing bacteria (SRB) and archaea-generating hydrogen sulfide. However, as the reservoir fluid flows from injection well to topside facilities, reactions involving formation of different sulfur species with intermediate valence states such as elemental sulfur, sulfite, polysulfide ions, and polythionates can occur. A predictive reactive model was developed in this study to investigate the chemical reactivity of sulfur species and their partitioning behavior as a function of temperature, pressure, and pH in a seawater-flooded reservoir. The presence of sulfur species with different oxidation states impacts the amount and partitioning behavior of H2S and, therefore, the extent of reservoir souring. The injected sulfate is reduced to H2S microbially close to the injection well. The generated H2S partitions between phases depending on temperature, pressure, and pH. Without considering chemical reactivity and sulfur speciation, the gas phase under test separator conditions on the surface contains 1080 ppm H2S which is in equilibrium with the oil phase containing 295.7 ppm H2S and water phase with H2S content of 8.8 ppm. These values are higher than those obtained based on reactivity analysis, where sulfur speciation and chemical reactions are included. Under these conditions, the H2S content of the gas, oil, and aqueous phases are 487 ppm, 134 ppm, and 4 ppm, respectively. [ABSTRACT FROM AUTHOR]

An experimental study was conducted to evaluate the effectiveness of the measures for controlling ozone (O 3) pollution in Jinshan District, Shanghai, China during the summer months of June 2022–August 2022. The study period was divided into a control period (CP) when measures were enforced and a non-control period (NCP) without interventions. The concentrations of volatile organic compounds (VOCs) were compared between the two periods, with the ranking of various types of identical VOCs, in which alkanes exhibited the highest (39.48%) concentrations, followed by aromatics (24.35%), halohydrocarbons (19.94%) and alkenes (16.23%). Compared to NCP, the mean levels of VOCs were 32.67% lower in CP, indicating the control measures significantly reduced the concentrations of VOCs during the months when control measures were in effect. The typical bimodal O 3 pattern was eliminated during CP along with the absence of peak VOC levels between 10:00 Hrs and 16:00 Hrs, which surpassed the level of 40 μg/m3 during NCP. The analyses of O 3 formation potential (OFP) and rate of loss of OH radicals (L OH) indicated that alkenes and aromatics were the most chemically active VOCs driving the production of O 3. Following six types of sources were determined for VOCs using positive matrix factorization (PMF): (1) solvent use (8.2%); (2) fuel evaporation (25.1%); (3) petrochemical plant (17.3%); (4) LPG (20.1%); (5) industrial process (16.1%); (6) vehicular emissions (13.2%). Emissions from vehicles and solvent use declined by 19.21% and 15.43%, respectively, underscoring their importance as controllable VOC sources in Shanghai, China. Overall, the study demonstrated the effectiveness of regional control measures in improving air quality by reducing the production of O 3 and related VOCs. [Display omitted] • Characteristics and sources of VOCs in industrial parks in Shanghai were analyzed under different management periods. • Industrial process and vehicle exhaust were major sources of VOCs. • Controlling the emissions of alkenes and aromatics was crucial for mitigating regional ozone pollution. • Control measures in the summer of 2022 effectively reduced the VOCs emission. [ABSTRACT FROM AUTHOR]

• Molecular geometrical parameters were calculated for the synthesised compound in the gas phase. • Spectroscopic characterizations (FT-IR,FT-RAMAN and UV–Vis) were performed and compared the interpretations with the simulated data. • HOMO-LUMO energies, MEP map, electron-hole distribution analysis was carried out for the different solvents. • ELF, LOL and RDG were estimated for the different solvents. • Drug-likeness and ADMET properties evaluation were discussed. • Docking analysis was performed for various targeted protein inhibitors. Chalcones are a significant class of naturally occurring chemical substances and their derivatives are extremely influential in the field of biological industries. In the current study, the title composite,4 - Chlorochalcone has undergone extensive investigation to understand its spectral properties using a combination of experimental and theoretical calculations. Fourier transform (FT-IR) infrared and FT-Raman characterizations provided valuable insights into the vibrational assignments (functional groups) in the header molecule, while ultraviolet–visible (UV–Vis) spectroscopy explored its electronic transitions and absorbance characteristics. The electronic properties were studied for the solvents viz., ethanol, methanol, DMSO, acetonitrile and benzene through theoretical-computational DFT calculations, revealing details about their molecular orbitals, electronic energies, and other energy parameters. Additionally, the NBO- natural bond orbital analysis shed light on the chemical bonding and electron distributions by donor and acceptor atoms. Furthermore, MEP- molecular electrostatic potential was analyzed for the various solvents and the calculated energy parameters were obtained. A drug-likeness evaluation was performed to assess its potential as a drug candidate based on its molecular properties. Moreover, the topological analysis and electron-hole distributions, contributed to a comprehensive understanding of electron density and localization within the molecule for the solvents viz., ethanol, methanol, DMSO, acetonitrile and benzene. Molecular docking investigations, as well as the Ramchandran plots, revealed that substituents targeting amino acids contribute to the antiviral action of the header compound. The potential of 4′-Chlorochalcone (ligand) as an antiviral agent offers promising prospects for further exploration and development in various therapeutic areas within the field of medicinal chemistry. [ABSTRACT FROM AUTHOR]

The cannabinoid receptors (CB1/CB2) and the T-type calcium channels are involved in disorders associated with both physiological pain and depressive behaviors. Valuable pharmacological species carbazole derivatives such as the NMP-4, NMP-7, and NMP-181 (Neuro Molecular Production) regulate both biological entities. In this work, DFT calculations were performed to characterize theoretically their structural and chemical reactivity properties using the BP86/cc-pVTZ level of theory. The molecular orbital contributions and the chemical reactivity analysis reveal that a major participation of the carbazole group is in the donor-acceptor interactions of the NMP compounds. The DFT analysis on the NMP compounds provides insights into the relevant functional groups involved during the ligand-receptor interactions. Molecular docking analysis is used to reveal possible sites of interaction of the NMP compounds with the Cav3.2 calcium channel. The interaction energy values and reported experimental evidence indicate that the site denominated as “Pore-blocking”, which is formed mainly by hydrophobic residues and the T586 residue, is a probable binding site for the NMP compounds.

Modelling of the proline (1) catalyzed aldol reaction (with acetone 2) in the presence of an explicit molecule of dimethyl sulfoxide (DMSO) (3) has showed that 3 is a major player in the aldol reaction as it plays a double role. Through strong interactions with 1 and acetone 2, it leads to a significant increase of energy barriers at transition states (TS) for the lowest energy conformer 1a of proline. Just the opposite holds for the higher energy conformer 1b. Both the ‘inhibitor’ and ‘catalyst’ mode of activity of DMSO eliminates 1a as a catalyst at the very beginning of the process and promotes the chemical reactivity, hence catalytic ability of 1b. Modelling using a Molecular-Wide and Electron Density-based concept of Chemical Bonding (MOWED-CB) and the Reaction Energy Profile–Fragment Attributed Molecular System Energy Change (REP-FAMSEC) protocol has shown that, due to strong intermolecular interactions, the HN-C-COOH (of 1), CO (of 2), and SO (of 3) fragments drive a chemical change throughout the catalytic reaction. We strongly advocate exploring the pre-organization of molecules from initially formed complexes, through local minima to the best structures suited for a catalytic process. In this regard, a unique combination of MOWED-CB with REP-FAMSEC provides an invaluable insight on the potential success of a catalytic process, or reaction mechanism in general. The protocol reported herein is suitable for explaining classical reaction energy profiles computed for many synthetic processes.

Volatile organic compounds (VOCs) are important precursors of photochemical ozone and secondary organic aerosol (SOA). Here, hourly variations of ambient VOCs were monitored with an online system at an urban site (Panyu, PY) in the Pearl River Delta region during August–September of 2020 in order to identify reactive VOC species and major sources of VOCs, OH loss rate (LOH), SOA formation potential (SOAFP), and corresponding emission source regions. The average concentration of VOCs at PY was 31.80 ± 20.82 ppbv during the campaign. The C2–C5 alkanes, aromatics, and ≥C6 alkanes contributed for the majority of VOC, alkenes and aromatics showed the highest contribution to LOH and SOAFP. Further, m/p-xylene, propene, and toluene were found to be the top three most reactive anthropogenic VOC species, with respective contributions of 11.6%, 6.1%, and 5.8% to total LOH. Toluene, m/p-xylene, and o-xylene constituted a large fraction of calculated SOAFP. Seven major sources were identified by using positive matrix factorization model. Vehicle exhaust made the most significant contribution to VOCs, followed by liquefied petroleum gas and combustion sources. However, industrial-related sources (including industrial solvent use and industrial process emission) had the largest contribution to LOH and SOAFP. By combining source contribution with wind direction and wind speed, the regions of different sources were further identified. Based on high-resolution observation data during ozone pollution, this study clearly exhibits key reactive VOC species and the major emission regions of different VOC sources, and thus benefits the accurate emission control of VOCs in the near future.

Abstract Background Nitroaromatic and chloronitroaromatic compounds have been a subject of great interest in industry and recently in medical-pharmaceutic field. 2-Chloro-4-nitro/2-chloro-5-nitrobenzoic acids and 4-nitrobenzoic acid are promising new agents for the treatment of main infectious killing diseases in the world: immunodeficiency diseases and tuberculosis. Results New ethanolamine nitro/chloronitrobenzoates were synthesized and characterized by X-ray crystallography, UV–vis, FT-IR and elementary analysis techniques. The toxicity of the compounds prepared and correspondent components was evaluated using Hydractinia echinata as test system. A significant lower toxicity was observed for nitro-derivative compared with chloronitro-derivatives and individual components. Crystallographic studies, together with the chemical reactivity and stability profiles resulted from density functional theory and ab initio molecular orbital calculations, explain the particular behavior of ethanolamine 4-nitrobenzoate in biological test. Conclusions The experimental and theoretical data reveal the potential of these compounds to contribute to the design of new active pharmaceutical ingredients with lower toxicity.

Effects of substituent groups on aqueous solubility, chemical reactivity and absorption wavelength of Disperse red 73 (DR73) were theoretically investigated using density functional theory (DFT) method. This study is in view of introducing new monoazo disperse dyes with improved aqueous solubility, absorption behaviour, and degradation tendency. Aqueous solubility was calculated using Cramer et al. solubility equation and the parameters used were obtained using conductor-like screening model for realistic solvation (COSMO-RS). Chemical reactivity and catalytic affinity were evaluated using some molecular orbital dependent reactivity descriptors. Susceptibility of the molecules to radical attacks was predicted using Fukui functions. Absorption wavelength was calculated using the B3LYP functional with the 6-31G* basis set. The results showed that electron withdrawing −CN substituent promoted aqueous solubility of DR73 more than the −NO2 counterpart, while the solubility is mostly enhanced by −NH2 substituent compared to the other electron donating groups studied. Most of the derivatives yielded longer absorption wavelength in the visible region and are chemically less stable (i.e. more degradable) compared to the parent molecule. Among the photocatalysts considered, ZnO is predicted as the most efficient candidate for degradation of the dyes. Predicted properties showed remarkable sensitivity to substitution positions in the parent molecule. [ABSTRACT FROM AUTHOR]

There is currently no quick available method for assessing chemical reactivity of liming materials used to neutralize soil acidity. This study was conducted to assess the effectiveness of a method developed to determine the chemical reactivity of liming materials. The reactivity of five conventional liming materials, biochar, charcoal and wood ash was determined using the method. Liming materials were applied to surface samples of two Ultisols at rates intended to neutralize exchangeable acidity. Physico-chemical and mineralogical properties of liming materials and soils were determined. Soils treated with the liming materials were incubated for 12 weeks in plastic containers using a soil: water ratio of 1:1. The pH and exchangeable acidity of the samples were measured every fortnight. The reactivity of the conventional liming materials was found to be strongly and positively (r = 0.99) correlated with their calcite contents, and strongly and negatively (r = −0.98) correlated with their dolomite contents. Strong positive linear relationships (R2 ≥ 0.79, p <.05) were observed between the reactivity and mean pH of the two soils between the 2nd and the 12th week, while strong negative linear relationship (R2 ≥ 0.79, p <.05) was observed between the reactivity and mean exchangeable acidity of the soils. Conventional liming materials were better than biochar and charcoal in neutralizing acidity. The new method was effective in predicting the ability of liming materials to neutralize exchangeable acidity and to raise the pH of acid soils. It can be used by farmers and lime producers to assess the reactivity of liming materials. [ABSTRACT FROM AUTHOR]

Copyright of Research of Environmental Sciences is the property of Research of Environmental Sciences Editorial Board 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.)

Many infaunal marine invertebrates produce mucus excretions that play an important role in metal binding, authigenic mineralization and burrow stabilization. To date, only a handful of studies have characterized the functional groups that control the surface reactivity of burrow linings and backfills. This makes it difficult to place estimates on the overall impact that bioturbation has on metal cycling in tidal flats, the inner shelf, estuaries and other shallow marine environments. Here, we examined the parchment linings of Diopatra cuprea burrows from the Ogeechee River estuary near Savannah, Georgia, USA. Acid–base titrations coupled with Fourier transform infrared spectroscopy demonstrate that the parchment is essentially composed of hydroxyl (R‐OH) groups, yielding total ligand densities of only 0.017 mmol/g. To place this value into context, it is orders of magnitude less than previously reported mucopolysaccharides for other marine worms, indicating that D. cuprea is essentially unreactive in the estuarine waters from which it was collected. This was corroborated by minimal Cd2+ adsorption to, and limited silicification of, pre‐rinsed parchment. The lack of silica adsorption was surprising given that the parchment was generally coated with an abundance of quartz grains when extracted from the sediment. This suggests that perhaps the physical, rather than chemical, characteristics of the parchment material were responsible for this association. Indeed, scanning electron microscope images show that the parchment is fibrous and envelopes quartz grains, implying that detritus may get trapped by the parchment mesh. It appears that unlike many other infaunal mucopolysaccharide‐rich linings that might be produced to provide reactive surfaces to which dissolved metal cations can adsorb for the organism's nutritional benefit, the parchment of D. cuprea may instead function to protect the animal from stresses such as predation or high‐energy disturbances. [ABSTRACT FROM AUTHOR]

Isopimpinellin (C13H10O5), alternative name 5,8-dimethoxypsoralen, is one of the furocoumarin compounds. This traditional Chinese medicine extract has attracted a great deal of attention in recent years due to its pharmacological properties, especially its antifungal effect. The main purpose of this study was to study the molecular structure and chemical reactivity of isopimpinellin using the density functional theory method. To understand and interpret the reactivity of isopimpinellin, various chemical reactivity descriptors such as chemical potential (µ), electronegativity (ɰ), chemical hardness (ɳ) and electrophilicity (w) and local reactivity index condensed Fukui function (fi(r)) have been calculated with five hybrid functionals PBE1PBE, MPW1PW91, B3LYP, X3LYP and B3PW91. These chemical reactivity descriptors indicate that the isopimpinellin molecule has a good antioxidant activity, which could be one of the reasons for its action as an effective antifungal drug. The condensed Fukui functions of isopimpinellin molecule provide a complete scheme of chemical reactivity of one molecule. [ABSTRACT FROM AUTHOR]

Approaches for the preparation of cyanoacetamide derivatives as well as the chemical reactivity profiles and structures of these substances are reviewed. The utility of these compounds as precursors is emphasized in the synthesis of five- and six-membered heterocycles and their fused heterocycles. The reported heterocyclic compounds in this review article are classified according to the kind of the heterocyclic systems. [ABSTRACT FROM AUTHOR]

The harmine derivatives were comprehensively investigated by computational tools to predict the structural, electronic, and spectroscopic properties as well as the chemical reactivity behavior. Physicochemical parameters showed that the harmine derivatives (H2 and H4) containing the –OH group at 2-position were more stabilized with the solvent dielectric constant than those of the other compounds (H1 and H3) including the –OCH3 substitution at 2-position. The PED analysis was used to assign the vibrational modes of all stable conformers of the harmine derivatives. TD-DFT simulations revealed that the lowest energy excitations were related to the H → L transition, which was mainly characterized by n → π* for H1 and H2 compounds and π → π* for H3 and H4 compounds. According to NBO analysis results, the highest contribution to the lowering of the molecular stabilization energy for all compounds was mainly due to the intramolecular charge transfer from the lone pair of the N atom as a donor orbital to π* as an acceptor orbital. Global reactivity descriptors obtained from B3LYP/6-311++G(d,p) level implied that the trans-conformers of the studied compounds could be relatively more effective in their interaction with DNA, while the cis-conformers of them could be more eager to interact with the BSA molecule. Harmine derivatives are investigated by computational tools to predict the structural, electronic, and spectroscopic properties. Global reactivity descriptors implied that the trans-conformers of the compounds could be relatively more effective to interact with DNA, while the cis-conformers could be more eager to interact with the BSA molecule. [ABSTRACT FROM AUTHOR]

Copyright of Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales is the property of Academia Colombiana de Ciencias Exactas, Fisicas y Naturales 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.)

Wet vacuum impregnation method was applied in order to evaluate the possibility of the formation of the material in BaCe0.9Y0.1O3−δ–V2O5 system. Single-phase BaCe0.9Y0.1O3−δ samples, synthesised by solid-state reaction method, were impregnated with the solution of vanadium(V) oxide precursor. Multi-step, multi-cycle impregnation procedure was applied to enhance the impregnation efficiency. Partial decomposition of Y-doped BaCeO3 in contact with the solution of the precursor, resulting in the formation of vanadium containing phases (CeVO4 and BaV2O6) on the materials surface, was observed. However, the presence of vanadium was also confirmed for the inner parts of the materials. The synthesised materials were submitted for exposition test to evaluate their chemical stability towards CO2/H2O. All BaCe0.9Y0.1O3-based materials modified by impregnation revealed higher chemical stability in comparison with single-phase un-modified BaCe0.9Y0.1O3−δ, since the amount of barium carbonate formed during the exposition was significantly lower. The total electrical conductivity of the received multi-phase materials was generally slightly lower than for the reference BaCe0.9Y0.1O3−δ sample, since the presence of the additional phases had a blocking effect on materials conductivity. The values of BaCeO3 lattice parameters and the Seebeck coefficient did not show the modification of the defects structure of Y-doped BaCeO3 during applied synthesis procedure. [ABSTRACT FROM AUTHOR]

Wet vacuum impregnation method was applied in order to evaluate the possibility of the formation of the material in BaCe0.9Y0.1O3−δ–V2O5 system. Single-phase BaCe0.9Y0.1O3−δ samples, synthesised by solid-state reaction method, were impregnated with the solution of vanadium(V) oxide precursor. Multi-step, multi-cycle impregnation procedure was applied to enhance the impregnation efficiency. Partial decomposition of Y-doped BaCeO3 in contact with the solution of the precursor, resulting in the formation of vanadium containing phases (CeVO4 and BaV2O6) on the materials surface, was observed. However, the presence of vanadium was also confirmed for the inner parts of the materials. The synthesised materials were submitted for exposition test to evaluate their chemical stability towards CO2/H2O. All BaCe0.9Y0.1O3-based materials modified by impregnation revealed higher chemical stability in comparison with single-phase un-modified BaCe0.9Y0.1O3−δ, since the amount of barium carbonate formed during the exposition was significantly lower. The total electrical conductivity of the received multi-phase materials was generally slightly lower than for the reference BaCe0.9Y0.1O3−δ sample, since the presence of the additional phases had a blocking effect on materials conductivity. The values of BaCeO3 lattice parameters and the Seebeck coefficient did not show the modification of the defects structure of Y-doped BaCeO3 during applied synthesis procedure. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) is used for investigating the electronic structure and optical properties carbon nanotubes (CNTs) with doped B, Al, Ga, Si, Ge, N, P and As and different diameters. Our results show that the stability of CNTs increased when it comes to an increase in diameter, however, stability decreases depending on doping additives to pure CNTs. B-doped CNTs are the most effective for electronic conductivity due to its lower band gap. The non-linear optical (NLO) properties are discussed according to dipole moment, polarizability, and hyperpolarizability. All the doped CNTs exhibit a good NLO activity. B-, Al-, Ga- and N -doped CNTs have a significant effect on NLO properties. The band gap of CNTs considerably decreased from 2.76 eV to 1.40 eV and 1.78 eV–0.83 eV based on the diameter. The reactivity properties investigated based on chemical hardness, softness, and potential, electronegativity, electrophilicity, the maximum amount of electronic charge index, the electron accepting and donating capability as well as electronic density of states are also presented and analyzed. Herein, the results indicated that the characteristic properties of CNTs can be controlled with different atoms doped CNTs and diameters. • The analyses of the energetic of pure and doped CNTs are investigated in detail. • The electronic and reactivity properties of pure and doped CNTs are compared. • The characteristic properties of CNTs can be controlled based on doped atoms. • B-doped CNTs have desirable electronic conductivity. [ABSTRACT FROM AUTHOR]

High-temperature impregnation of solid single-phase Y-doped BaCeO 3 with melted WO 3 was performed towards the evaluation of the possibility of formation of chemically stable material with relatively high electrical conductivity in this system. Impregnation was performed at 1470 °C as a function of time. Due to the relatively high reactivity in solid BaCe 0.9 Y 0.1 O 3-δ - liquid WO 3 system the reactive and the inner layers were distinguished and analysed. The obtained results clearly indicate the decomposition of Y-doped BaCeO 3 in contact with melted WO 3. X-ray diffraction method together with SEM observation, EDS analysis and EIS measurements results were applied to discuss the mechanism of this multi-stage process and the influence of the reaction time on materials structure and microstructure. As it was observed, partial incorporation of tungsten into the barium cerate structure can process not only on the surface of the materials but also in the inner layer of the synthesised materials. This donor-type doping of the perovskite structure finds reflection in both, materials electrical properties and chemical stability towards CO 2 /H 2 O. The decrease of proton defects concentration was observed together with the significant increase of the materials chemical stability in comparison to un-modified single-phase BaCe 0.9 Y 0.1 O 3-δ. The calculated values of activation energy of conductivity confirm the change in the conduction mechanism. Also, the presence of an additional phase in the intergranular voids of doped BaCeO 3 was postulated. • Decomposition of BaCe 0.9 Y 0.1 O 3 in the contact with melted WO 3. • Incorporation of tungsten into Y-doped BaCeO 3 structure. • The increase of the activation energy of conductivity - conduction mechanism change. [ABSTRACT FROM AUTHOR]

Copyright of Research of Environmental Sciences is the property of Research of Environmental Sciences Editorial Board 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.)

Abstract The purpose of this article is to predict the molecular structure of the cocrystal of dipfluzine-benzoic acid (DIP-BEN) through computational approach (DFT calculations) and validate it using vibrational spectroscopic studies. The molecular structure of the DIP-BEN cocrystal has been predicted by forming models on the basis of the active sites available to form H-bonds between dipfluzine (DIP) and benzoic acid (BEN). Conformational study has been performed and potential energy surface scans are plotted around the flexible bonds of the cocrystal molecule and three stable conformers have been obtained. Quantum theory of atoms in molecules (QTAIM) explains that all the interactions are medium and partially covalent in nature. Natural bond orbital analysis of the second order perturbation theory of the Fock matrix suggests that interactions LP (2) O2 → σ*(O74 H75) and LP (2) F1 → σ* (O89 H90) are responsible for the stabilization of the molecule. The HOMO and LUMO energies and electronic charge transfer (ECT) confirms that charge flows from BEN to DIP. Global reactivity descriptor parameters suggest that DIP-BEN cocrystal is softer, thus more reactive in comparison to DIP. Local reactivity descriptor parameter is used to predict reactive sites of the cocrystal. The experimental and theoretical results support the formation of cocrystal through strong hydrogen bond (O89 H90⋯F1 and O74 H75⋯O2) interactions present in cocrystal. Graphical abstract Unlabelled Image Highlights • Molecular structure of dipfluzine-benzoic acid cocrystal has been proposed. • Geometry optimization and conformational study has been done to predict the best possible model. • Spectroscopic (FT-IR and FT-Raman) study of dipfluzine cocrystal has been done. • NBO and AIM analysis have been done for the understanding of charge transfer within the cocrystal. • Global and local reactivity descriptors are used to determine chemical reactivity and site selectivity. [ABSTRACT FROM AUTHOR]

In this study, solvent effects on the structural and spectroscopic properties of the naringenin have been investigated. Geometric parameters were calculated and were compared with the experimental X-ray crystallographic data. In addition, optimized structures were obtained in solvent media and the solvents effects on geometric parameters were determined. Vibrational modes obtained in the vacuum and in solvent environments were compared with the experimental IR spectrum. Furthermore, the HOMO-LUMO energies and chemical reactivity were also determined. Antioxidant activity of naringenin has been investigated with hydrogen atom abstraction from -OH groups. The bond dissociation enthalpies have been calculated and it is determined that this process should be the main mechanism for the antioxidant activity of naringenin. According to the calculation results, surprisingly, it has been found that in DMSO, BDE values of naringenin are significantly reduced and thus antioxidant activity is increased compared to other media. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ag(I)-azine complex was obtained by hydrolysis of pyridine oxamohydrazide with AgNO 3. • The [Ag 2 L(NO 3) 2 ] n 2D coordination polymer is built by NAgO and OAgO backbones. • Its structural aspects were studied using SCXRD, NMR spectra and DFT calculations. • The coordination behavior of L was described using QST2 calculations. • No reactions between halo-isatin oxamohydrazides and AgNO 3 were observed. Abstract The novel [Ag 2 L(NO 3) 2 ] n complex, where L is (1 E ,2 E)-1,2- bis (pyridin-2-ylmethylene)hydrazine, was synthesized via self-assembly of AgNO 3 and the condensation product (E)-2-oxo-2-(2-(pyridin-2-ylmethylene)hydrazinyl)acetamide (L 1) of pyridine-2-carboxaldehyde and oxamohydrazide. The Ag(I) promoted formation of the azine ligand L was occurred in the reaction mixture followed by in situ complexation with Ag(I) yielding the [Ag 2 L(NO 3) 2 ] n complex in a good yield. The azine ligand (L) acts as a bridged bidentate chelate via two Ag-N interactions with the pyridine and azine N -atoms. The coordination sphere of Ag(I) ion is completed by two Ag-O interactions from two nitrate ions. The supramolecular structure of the [Ag 2 L(NO 3) 2 ] n complex could be described as a two dimensional coordination polymer of complex units connected by Ag N and Ag O coordination interactions. The polymeric structure of the studied complex was revealed by Hirshfeld analysis and the Ag N/Ag O bonding interactions were described using DFT calculations. Conformational analysis combined with a study on the thermodynamic and kinetic stabilities of the possible conformers of L were also discussed. No reaction was observed in case of the halo-substituted derivatives of isatin oxamohydrazide which is explained in terms of the Parr reactivity parameters. [ABSTRACT FROM AUTHOR]

The preparation and the properties of the elusive tetronic acid are reviewed, including its synthesis, chemical reactivity and reactions. [ABSTRACT FROM AUTHOR]

Abstract In this work the reactivity in solid BaCe 0.9 Y 0.1 O 3-δ - liquid V 2 O 5 system was investigated in order to evaluate the possibility of composite formation in this system. Impregnation of melted vanadium(V) oxide into solid Y-doped BaCeO 3 was performed in various temperature and time conditions. Due to the relatively high reactivity of components in this system an analysis of the synthesized materials was divided into discussion of the properties of the reactive layer and the inner part. As was shown, decomposition of Y-doped BaCeO 3 in contact with melted vanadium(V) oxide occurs already at temperature 700 °C and results in formation of CeVO 4 as one of the main phases. Moreover, the presence of Ba 8 V 7 O 22 as the intermediate phase was observed. The extension of reaction time and increase of temperature resulted in significant changes in the microstructure and chemical composition of the reactive layer. The incorporation of vanadium into yttrium doped BaCeO 3 structure for inner parts of the synthesized materials was postulated based on the modification of the materials electrical properties and chemical stability towards CO 2 and H 2 O. Also, the presence of additional phase in the intergranular voids of doped-BaCeO 3 was suggested. [ABSTRACT FROM AUTHOR]

Several efforts have been dedicated to the development of lignin-based polyurethanes (PU) in recent years. The low and heterogeneous reactivity of lignin hydroxyl groups towards diisocyanates, arising from their highly complex chemical structure, limits the application of this biopolymer in PU synthesis. Besides the well-known differences in the reactivity of aliphatic and aromatic hydroxyl groups, experimental work in which the reactivity of both types of hydroxyl, especially the aromatic ones present in syringyl (S-unit), guaiacyl (G-unit), and p-hydroxyphenyl (H-unit) building units are considered and compared, is still lacking in the literature. In this work, the hydroxyl reactivity of two kraft lignin grades towards 4,4′-diphenylmethane diisocyanate (MDI) was investigated. 31P NMR allowed the monitoring of the reactivity of each hydroxyl group in the lignin structure. FTIR spectra revealed the evolution of peaks related to hydroxyl consumption and urethane formation. These results might support new PU developments, including the use of unmodified lignin and the synthesis of MDI-functionalized biopolymers or prepolymers.

• Computational and experimental work has been performed on cocrystal of hydrochlorothiazide (HCTZ) and nicotinamide (NCT). • H-bonding interaction was studied by using monomeric, dimeric and trimeric models of HCTZ-NCT cocrystal. • NH 2 and C = O groups were involved in neighbouring hydrogen bonding interactions. • QTAIM and NBO analysis were done to explore inter and intramolecular H-bond interactions. • MEPS was performed to observe the reactive sites of the molecules. The present work focuses on the study of structural, vibrational, chemical properties and the effect of hydrogen bonding interaction in the formation of a cocrystal of hydrochlorothiazide (HCTZ, a diuretic drug) with nicotinamide (NCT) using vibrational spectroscopy (FT-IR and FT-Raman) and density functional theory. HCTZ being a BCS class IV drug, has low permeability and solubility; therefore, its cocrystal is studied. Monomer, dimer and trimer of HCTZ-NCT cocrystal were studied to understand hydrogen bonding interactions. The shifting in the wavenumber and the elongation in bond lengths of the amide (NH 2) group of HCTZ and carbonyl (C = O) group of NCT were observed in all the models of HCTZ-NCT cocrystal due to the hydrogen bonding interaction. The importance of hydrogen bonding were also explored by natural bond orbital (NBO) analysis in support of the quantum theory of atom in molecules (QTAIM). The chemical reactivity of HCTZ, NCT and HCTZ-NCT cocrystal was examined by MEPS map, FMOs, global electronic reactivity descriptor, ECT descriptors, and molar refractivity. The lesser value of the HOMO-LUMO energy gap in the cocrystal than API reflects that the chemical reactivity of the cocrystal was better than API itself. The comparison between API(HCTZ) and cocrystal (HCTZ-NCT) implies that pharmaceutical cocrystals may be a better option to improve and enhance the pharmacological properties of drugs. [Display omitted] [ABSTRACT FROM AUTHOR]

Considerable volumes of dust are generated from open-pit bitumen mining operations in northern Alberta, Canada. The reactive mineral phases of these dust particles can potentially dissolve in acidic (pH < 4) bog waters. Their dissolution could release trace elements (TEs), which could eventually alter these bog ecosystems. The impact of dust dissolution on the abundance of TEs in the dissolved (<0.45 μm) fraction of porewaters from excavated pits (30–40 cm deep) in the ombrogenic zone of five peatlands was evaluated. Porewaters were collected from four bogs situated within 70 km of mines and upgraders in the Athabasca Bituminous Sands (ABS) region, Alberta, Canada, and from a reference bog situated 264 km away. Over two consecutive years, the dissolved concentrations of some conservative (Al, Th, Y) and mobile lithophile elements (Fe, Li, Mn, Sr), as well as the metals enriched in bitumen (V, Ni, Mo), all increased with proximity to the mining area, in the ABS region. These trends reflect the observed increase in dust deposition with proximity to the mining area from independent studies of snow, lichens, and Sphagnum moss. Contrarily, the impact of dust dissolution on the concentration of potentially toxic TEs (As, Cd, Pb, Sb, and Tl) was negligible. Thus, the elements which are more abundant in the porewaters near industry are either ecologically benign (e.g. Li and Sr) or essential micronutrients (e.g. Fe, Mn, Ni, and Mo). Manganese was the only element which was enriched by more than 10x at all sites near the mining area, compared to its concentration at the reference site. The enrichments of all other elements were <10x, indicating that anthropogenic dust emissions from mining areas have had only a modest effect on the TEs abundance in peat porewaters. [Display omitted] • Trace elements (TEs) in bog porewaters were used as indicators of dust dissolution. • Micronutrients (Fe, Mn, Mo, Ni) in bog waters increased toward industry. • Arsenic, Cd, Pb, Sb, and Tl showed relatively little spatial variation. • Compared to the reference site, TE enrichments in waters near industry were modest. • Dusts from bitumen mining had a minimal impact on the dissolved forms of most TEs. [ABSTRACT FROM AUTHOR]

Due to the greenhouse effect and fossil fuel shortages, biochar became a research priority to replace charcoal for metallurgical-grade silicon reductants, but it has an uneven particle size and insufficient strength. In this study, biochar was pelletized and compared with charcoal, and the relationship between the biochar particle size and pellet strength, porosity, and reactivity was determined. The results showed that the performance of biochar pellets was better than that of charcoal. In addition, upon decreasing the biochar particle size, the pellet strength increased, the porosity decreased, and the reactivity increased. When biochar with a particle size of <100 μm was used, the strength of the pellets was 3184.63 N, the porosity was 47.85%, and the reactivity was 82.15%, which meets the requirements of metallurgical-grade silicon reducing agents. This study provides a reference for the production of biochar pellets suitable for smelting to reduce the production of greenhouse gases. [Display omitted] • Biomass gasification residues were used to replace fossil fuels as reducing agents. • Biochar pellets can meet the requirements of metallurgical-grade silicon smelting. • The high AAEMs content in small-particle biochar can improve pellets' reactivity. • Reducing the biochar particle size improved the pellet quality. [ABSTRACT FROM AUTHOR]

The evolution of time-resolved spectroscopies has resulted in significant advancements across numerous scientific disciplines, particularly those concerned with molecular electronic states. However, the intricacy of molecular vibrational spectroscopies, which provide comprehensive molecular-level information within complex structures, has presented considerable challenges due to the ultrashort dephasing time. Over recent decades, an increasing focus has been placed on exploring the temporal progression of bond vibrations, thereby facilitating an improved understanding of energy redistribution within and between molecules. This review article focuses on an array of time-resolved detection methodologies, each distinguished by unique technological attributes that offer exclusive capabilities for investigating the physical phenomena propelled by molecular vibrational dynamics. In summary, time-resolved vibrational spectroscopy emerges as a potent instrument for deciphering the dynamic behavior of molecules. Its potential for driving future progress across fields as diverse as biology and materials science is substantial, marking a promising future for this innovative tool. • Comprehensive review an array of innovative spectroscopic techniques designed to enhance the chemical and structural identification and characterization of molecular species. • Focus on utilizing the dynamic information about chemical bonds accessible through time-resolved molecular vibrational spectroscopy. • Innovative strategy to overcomes the limitations of conventional spectroscopy. • Exploration of vibrational dephasing in the time domain to reveal intra- and inter-molecular interactions. • Recent advancements in time-resolved spectroscopies pinpointing critical areas where these techniques could foster innovations and applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • FT-IR theoretical data were determined from B3LYP/ LANL2DZ basis set. • HOMO-LUMO energies, NBO property of the title compound are predicted. • MEP, Hirshfeld, IRI and ED were estimated. • Fukui function, ADMET and PASS were discussed. • Molecular docking predictions for the title drug have an antiviral and antioxidant activity. As focuses on a set of pertinent compounds that incorporate a γ-substituted halophenol linkage with pentanamide (PA). The properties of these compounds were comprehensively assessed through various analytical techniques, including density functional theory (DFT) calculations, offering insights into their geometry and electronic energy gap characteristics. Charge delocalization and stability were explored via natural bond orbital (NBO) analysis. The chemical reactivity was further scrutinized by evaluating NBO, Molecular Electrostatic Potential (MEP), Hirshfeld surface analysis and Fukui functions. The compounds were found to exhibit stability attributed to a robust hydrogen bonding network, which was corroborated by Interaction Region Indicator (IRI) and Electron Density (ED) assessments. Additionally, pharmacological properties were predicted using the PASS (Prediction of Activity Spectra for Substances) server. Molecular docking studies suggested potential antiviral and antioxidant properties, particularly concerning carbonic anhydrase. The overall results imply that these compounds possess favorable drug-like characteristics and show promise for biological efficacy. The study also includes a 2D interaction profile image of the four most interacted proteins and a Ramachandran plot to elucidate the stereochemistry of a selected protein. Furthermore, the activities of 6FDM were investigated following a comprehensive literature survey, with detailed findings presented. [ABSTRACT FROM AUTHOR]

[Display omitted] • Transforming MPs into partially oxidized materials enhances their reactivity. • Graphite particles create hot spots on MPs surface by MW radiation. • Incorporation of H 2 O 2 during MW treatment boosts MP oxidation. • Aliphatic plastics activate more effectively than aromatic plastics. • MW treatment improves MP conversion and solubilized TOC in CWPO process. Microplastics (MPs) are persistent environmental pollutants that demand innovative recycling strategies. This study introduces a novel method for rapid MP activation using microwave (MW) heating in aqueous phase. The activation process has been elucidated by detailed characterization of both the MPs and the aqueous matrix. Also, the effect of operating conditions, such as MP particle size, graphite and H 2 O 2 doses, temperature and reaction time on the physical and chemical properties of the MPs and the solubilized total organic carbon (TOC) has been studied. The results indicate that the activated MPs exhibit a rougher texture, surface holes, reduced particle size, higher oxygen content, and increased thermal instability. Furthermore, oxidized short-chain organic acids, including acetic, oxalic, and formic acids, are detected in the aqueous phase. The degree of activation achieved, measured by a parameter defined as A, accounts for weight loss and decomposition temperature changes in the activated MPs. Aliphatic plastics (LDPE, PP) show higher activation levels (A up to 40 %) compared to aromatic plastics (PS, PET, PC), with the activation order being: LDPE > PP > PS ∼ PC > PET. LDPE and PP can be effectively activated at 120 °C within 10 min using a MP:H 2 O 2 mass ratio of 1:1. In contrast, PS, PC, and PET require higher temperatures (200 °C), longer reaction times (180 min) or a greater H 2 O 2 dose (MP:H 2 O 2 mass ratio of 1:5). Activation efficacy is mainly influenced by the reaction time and H 2 O 2 dose. The activated MPs improve recyclability through the CWPO process, achieving up to 15 times higher MP conversion and increased solubilized TOC compared to non-activated MPs, all while consuming less H 2 O 2 and requiring shorter reaction times. This study demonstrates that MW activation has the potential to facilitate large-scale MP chemical recycling. [ABSTRACT FROM AUTHOR]

Intense electric fields applied on H-bonded systems are able to induce molecular dissociations, proton transfers, and complex chemical reactions. Nevertheless, the effects induced in heterogeneous molecular systems such as methanol-water mixtures are still elusive. Here we report on a series of state-of-the-art ab initio molecular dynamics simulations of liquid methanol-water mixtures at different molar ratios exposed to static electric fields. If, on the one hand, the presence of water increases the proton conductivity of methanol-water mixtures, on the other, it hinders the typical enhancement of the chemical reactivity induced by electric fields. In particular, a sudden increase of the protonic conductivity is recorded when the amount of water exceeds that of methanol in the mixtures, suggesting that important structural changes of the H-bond network occur. By contrast, the field-induced multifaceted chemistry leading to the synthesis of e.g., hydrogen, dimethyl ether, formaldehyde, and methane observed in neat methanol, in 75:25, and equimolar methanol-water mixtures, completely disappears in samples containing an excess of water and in pure water. The presence of water strongly inhibits the chemical reactivity of methanol.

In this paper, the antiestrogenic properties of Tamoxifen analogs have been investigated and a theoretical report of its analogs interaction with the pocket site of some hormone receptors are presented. Analogs were generated by modification of the hydrophilic functional group of Tamoxifen by hydroxyl, amide, carboxyl, and sulfhydryl functional groups, in an attempt to improve their activity and selectivity. The analogs exhibit a negative binding energy in the estrogen and progesterone receptors, which indicates a spontaneous interaction between the analogs and the pocket site in the hormone receptors. The values of the molecular polar surface area indicate that the analogs have good permeability and are strong electrophiles. The couplings showed electrostatic interactions such as hydrogen bond and π-π interactions. According with the Lipinsky Rule of Five, the four analogs presented a good biodistribution, permeability, and pharmacological action on the hormone receptors. The analysis of the charge transfer suggests a limited enhanced oxidative damage in the estrogen receptor that not takes place with the progesterone receptor.

This computational study assessed eight fixed RSH (range-separated hybrid) density functionals that include CAM-B3LYP, LC-ωPBE, M11, MN12SX, N12SX, ωB97, ωB97X, and ωB97XD related to the Def2TZVP basis sets together with the SMD solvation model in the calculation the molecular structure and reactivity properties of the BISARG intermediate melanoidin pigment (5-(2-(E)-(Z)-5-[(2-furyl)methylidene]-3-(4-acetylamino-4-carboxybutyl)-2-imino-1,3-dihydroimidazol-4-ylideneamino(E)-4-[(2-furyl)methylidene]-5-oxo-1H-imidazol-1-yl)-2-acetylaminovaleric acid) and its protonated derivative, BISARG(p). The chemical reactivity descriptors for the systems were calculated via the Conceptual Density Functional Theory. The choice of active sites applicable to nucleophilic, electrophilic as well as radical attacks were made by linking them with Fukui functions indices, electrophilic and nucleophilic Parr functions, and the condensed Dual Descriptor Δf(r). The study found the MN12SX and N12SX density functionals to be the most appropriate in predicting the chemical reactivity of the molecular systems under study starting from the knowledge of the HOMO, LUMO, and HOMO-LUMO gap energies.

Context: Finding catalysts that do not rely on the use of expensive metals is one of the requirements to achieve sustainable production. The reactivity of graphene doped with 3d transition metals was studied. All dopants enhanced the reactivity of graphene and performed better than Stone-Wales defects and divacancies, but were inferior to monovacancies. For hydrogenation of doped-monovacancies, Sc, Ti, Cr, Co, and Ni induced more prominent reactivity on the carbon atoms. However, the metals were the most reactive center for V, Mn, and Fe-doped graphene. Cu and Zn turned the four neighboring carbon atoms into the preferred sites for hydrogenation. The addition of oxygen to doped graphene with Ti, V, Cr, Mn, Fe, Co, and Ni on a monovacancy revealed a more uniform pattern since the metal, preferred to react with oxygen. However, Sc induced a larger reactivity on the carbon atoms. The affinity of the 3d metal-doped graphene systems towards oxygen was inferior to that observed for single-vacancies. Therefore, vacancy engineering is the most favorable and least expensive method to enhance the reactivity of graphene., Methods: We applied Truhlar's M06-L method accompanied by the 6-31G* basis sets to perform periodic boundary conditions calculations as implemented in Gaussian 09. The ultrafine grid was employed and the unit cells were sampled employing 100 k-points. Results were visualized employing Gaussview 5.0.1., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Compartmentalization and binding-triggered conformational change regulate many metabolic processes in living matter. Here, we have synergistically combined these two biorelevant processes to tune the Diels-Alder (DA) reactivity of a synthetic self-complexing host-guest molecular switch CBPQT 4+ -Fu, consisting of an electron-rich furan unit covalently attached to the electron-deficient cyclobis(paraquat-p-phenylene) tetrachloride (CBPQT 4+ , 4Cl - ) host. This design allows CBPQT 4+ -Fu to efficiently compartmentalize the furan ring inside its host cavity in water, thereby protecting it from the DA reaction with maleimide. Remarkably, the self-complexed CBPQT 4+ -Fu can undergo a conformational change through intramolecular decomplexation upon the addition of a stronger binding molecular naphthalene derivative as a competitive guest, triggering the DA reaction upon addition of a chemical regulator. Remarkably, connecting the guest to a thermoresponsive lower critical solution temperature (LCST) copolymer regulator controls the DA reaction on command upon heating and cooling the reaction media beyond and below the cloud point temperature of the copolymer, representing a rare example of decreased reactivity upon increasing temperature. Altogether, this work opens up new avenues towards combined topological and supramolecular control over reactivity in synthetic constructs, enabling control over reactivity through molecular regulators or even mild temperature variations., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Studies on the stable hemiaminals and Schiff bases formation in the reaction of substituted benzaldehydes with primary 3,5-dimethyl-1,2,4-triazole 4-amine were carried out under neutral conditions. These products were investigated by IR, Raman, MS, 1H- and 13C-NMR spectra as well as by X-ray crystallography. The effect of reaction conditions: temperature, polarity of the solvents utilized, substrate concentration and the ortho and para benzaldehyde substituents on the yield of products was also examined.