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The effect of solvents on kinetic parameters of anionic polymerization is complex and a comprehensive theoretical study has been rare. In this work, four solvent polarity descriptors (i.e., polarizability, dipole moment, nucleophilic index, electrophilic index) are correlated with solvent parameters (Ea, A, ΔH‡, and ΔS‡) by multiple linear regression using the Catalan linear free‐energy relationship (LFER) equation for the anionic polymerization of styrene. The results show that Ea, ΔH‡, and ΔS‡ have a low correlation with dipole moment, whereas A is strongly correlated with dipole moment. Given the fact that the larger A the larger effective collision frequency Z, it is hypothesized that in polar solvents, the polymer chains are more extended, enabling more effective collisions between monomers and active anionic species during polymerization. In contrast, in nonpolar solvents, the polymer chains collapse, making it more difficult for the monomer to be inserted into the ion pairs. Subsequently, n‐pentane and tetrahydrofuran are chosen as representatives to confirm this conjecture by molecular simulations. Lastly, Ea, A and kp are predicted for 173 solvents using well‐established descriptive relationships. [ABSTRACT FROM AUTHOR]

In recent decades, sulfur-containing compounds have played a significant role in biological applications because of their unique biological and chemical characteristics. Taurolidine, a sulfur-containing derivative of the amino acid taurine, has been characterized theoretically utilizing Density Functional Theory (DFT) at the B3LYP approach along with a 6-311++G(d,p) basis set. The impact of solvents on electronic characteristics, Molecular electrostatic potential (MEP), and Fourier Molecular Orbital (FMO) in polar (water and ethanol) and nonpolar (toluene and chloroform) has been analyzed. The bond distances of S1-C16 and S1-C17 have been simulated at 1.817 Å and observed at 1.743 and 1.739 Å, respectively. These distances are increased compared to other bond distances due to the influence of sulfur atoms. The distinctive simulated vibrational wavenumbers of taurolidine revealed peaks for SO2, CH2, CN, and NH groups. The intramolecular interactions responsible for stabilizing the molecular structure of taurolidine have been addressed using NBO analysis shows significant stabilization energy from electron-donating lone pair oxygen O6 to antibonding S2-N10 with the stabilizing energy of 19.88 KJ/mol by the transition of LP(3)-s*. The bonding characteristics and reactive sites (electron-rich and electron-poor) have been confirmed with Mulliken and MEP analysis. The carbons (C17 and C16) emphasize the increased negative potential due to the sulfonyl (SO2) group in the ortho position. The topological insights, ELF and LOL, were spotted using Multiwfn software, highlighting the localized and delocalized electron regions within the crystal structure. In addition, molecular docking was performed to predict the antagonist activity of taurolidine against ß-catenin protein, yielding a binding energy of -6.86 KJ/mol, which confirms its antiproliferative property. [ABSTRACT FROM AUTHOR]

The effect of the external electric field on the ground-state tautomerism in 8-(benzo[d]thiazol-2-yl)quinolin-7-ol has been studied by using density functional theory. The compound exists as an enol tautomer (off state) and under the influence of the external electric field a long-range intramolecular proton transfer can occur, placing the tautomeric proton at the quinolyl nitrogen atom (on state). This is a result of the much higher dipole moment of the end keto tautomer and indicates that the external electric field can be used to mimic the implicit solvent effect in tautomeric systems. In the excited state, the further stabilization of the most polar on state leads to a situation when the excited-state intramolecular proton transfer becomes impossible, limiting the intramolecular rotation to the conical intersection region. [ABSTRACT FROM AUTHOR]

The B3LYP/cc-pVDZ basis set was used to optimize the best results of Pacritinib whose systematic name is (E)- 44-(2-(pyrrolidin-1-yl) ethoxy) −6,11- dioxa-3- aza-2(4,2)- pyrimidine −1,4 (1,3)-dibenzenacyclododecaphan-8-ene (MJ). The NBO analysis confirm the highest stabilization energy 55.36 kcal/mol, from bonding LP (1)–N13 to anti-bonding π*(N10 - C11). The ELF, LOL, ALIE, and RDG, analysis was done by using Multiwfn software, and confirms the localization and delocalization electrons. The thermodynamical properties and electron density were calculated with help of Gaussian-16w software. Analyses of NLO parameters, MEP, UV-vis, and HOMO-LUMO were performed using five different solvents (chloroform, water, acetonitrile, ethanol and DMSO). Docking study was done, against 5C5S protein and we identify the protein-ligand interaction, the best binding score is −6.64 kcal/mol. [ABSTRACT FROM AUTHOR]

In this research project, a computational assessment of the molecular structure of Ipriflavone (IP) in the gaseous phase was done based on density functional theory (DFT). In the realm of theory, the standard basis set B3LYP is a collection of functions used with linear combinations to produce molecular orbitals, making it simple to compute the molecular structure related to the given compound. With the time-dependent DFT approach, the UV spectra obtained for various solvents were used for examining the electronic transport features. A three-dimensional representation of the molecules that shows the charge distributions and charge-related characteristics of the molecule has the acronym the electrostatic potential map. The frontier molecular orbitals (FMO) confirmed the compound's stability and good reactivity. Hyperpolarizability calculations were performed with good non-linear optical (NLO) potent. Natural bond orbital (NBO) analysis was used to explore charge delocalization and the compound's stability. Topological investigations have been identified to clarify the bonding zones, weakest contacts, and electron energy density. Drug likeness studies were used to promote bioactivities. The outcome of docking tests shows that the ligand under investigation is beneficial at preventing bone loss-osteoporosis. To sum up, this work provides a comprehensive analysis that combines spectroscopic and quantum computational techniques to assess the effect of specific medicinal compounds on solvation and metabolic activity. Strategies for subsequent studies can thus greatly benefit from the knowledge obtained. [ABSTRACT FROM AUTHOR]

The work presented here establishes the experimental findings of the reaction between secondary/tertiary propargylic alcohol (PA) and 1,3,5‐trimethoxybenzene (TMB) in the presence of acetonitrile solvent (MeCN) based on theoretical calculations. When secondary PA reacts, the reaction goes via SN2 pathway, where the reaction barrier is about 14.32 kcal/mol. On the other hand, tertiary PA reacts with TMB via SN2′ and SN1′ pathway, and the corresponding reaction barriers are 17.59 and 17.86 kcal/mol. Other possible pathways, namely, SN1, SN1′, etc. for secondary PA, and SN2, SN1 pathways for tertiary PA are also investigated and the associated barrier heights are found higher. Rates of those reactions are also calculated considering the rate‐determining steps only. Reaction of secondary PA with TMB is found to be much faster than the reaction of tertiary PA and the results are in accordance with the experimental findings. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel type of PILs has been fabricated. • PILs integrate the permanent pores of porous solids with the exceptional properties of ILs. • PILs possess high activity and selectivity for the DBT oxidation. • IL moiety serves as an extractant to enrich DBT and creates an electrostatic solvent effect. • UiO-66 moiety serves as a catalysis to handily catalyze the ODS reaction. Developing a highly efficient strategy for the stabilization of the solid-liquid interface is a persistent pursuit for researchers. Herein, porous ionic liquids based on UiO-66 (Zr) porous materials were synthesized and applied to the selective desulfurization catalysis, which integrates the permanent pores of porous solids with the exceptional properties of ionic liquids. Results show that porous ionic liquids possess high activity and selectivity for dibenzothiophene. Experimental analysis and density functional theory calculations revealed that the ionic liquids moiety served as an extractant to enrich dibenzothiophene into the porous ionic liquids phase through the π···π and C H···π interactions. Additionally, the electrostatic solvent effect in the porous ionic liquids contributes to the stabilization solid-liquid interface, which was favorable for UiO-66 moiety to catalytically activate hydrogen peroxide (H 2 O 2) to generate ·OH radicals, and subsequently oxidized dibenzothiophene to the corresponding sulfone. It is hoped that the development of porous ionic liquids could pave a new route to the stabilization of the solid-liquid interface for catalytic oxidation. [ABSTRACT FROM AUTHOR]

The tautomerism in the title compound as a potential long-range proton transfer (PT) switch has been studied by using the DFT and TD-DFT approaches. The data show that in aprotic solvents, the enol tautomer dominates, while the increase in the content of the keto tautomer (short-range PT) rises as a function of polarity of the solvent. In ethanol, due to specific solute–solvent stabilization through intermolecular hydrogen bonding, a substantial amount of the keto forms exists in solution. The irradiation leads to two competitive processes in the excited state, namely ESIPT and trans/cis isomerization around the azomethine bond as in other structurally similar Schiff bases. The studied compound is not suitable for bistable tautomeric switching, where long-range PT occurs, due to the difficult enolization of the coumarin carbonyl group. [ABSTRACT FROM AUTHOR]

The molecular structure of 1-(4-hydroxy-3-methoxyphenyl) ethenone has been optimized, and its various parameters were ascertained, using Density Functional Theory. The molecule's Fourier Transform-Infra Red and Raman spectra are recorded and examined. By comparing the computational and experimental results, molecular structure, bond length, and vibrational band intensity were all interpreted. The Integral Equation Formalism polarizable continuum model's depictions of electronic and Frontier Molecular Orbital solvent interaction investigations are sported to perceive the charge transfer among the atoms of the molecule in eco-green solvents such as water, acetone, and ethanol. The reactivity sites can be studied by locating and charting the electron density on the surface. The compound's hardness, softness, electrophilicity, and ionization potential were all analyzed. The pharmacological effects and intra-molecular hyper conjugative interactions are liable for its molecular stability, as shown by Natural Bond Orbital research. Topological studies, including Electron Localized Function, Localized Orbital Locator, and Reduced density gradient analysis, were performed to locate the compound's bonding area and Vander Waals interactions. Urea was used as a reference compound to examine the substance's non-linear optical characteristics. Total Density of States has investigated the role of molecular orbitals. Drug-likeness, a Ramachandran plot, and molecular docking were also performed to further analyze 1-(4-hydroxy-3-methoxyphenyl) ethanone's biological activity. The docking results lend credence to the idea that the title compound could function as a powerful cancer treatment. [ABSTRACT FROM AUTHOR]

The safrole and isosafrole are constitutional isomers that have been theoretically characterized utilizing Density Functional Theory (DFT) employed with the B3LYP/6-311++G(d,p) basis set to simulate geometrical parameters, vibrational aspects, electronic properties, and chemical shifts and explored the solvent effect on electronic spectra of safrole and isosafrole in different solvents, including polar solvents such as acetone, Dimethyl sulfoxide (DMSO), and methanol, nonpolar solvents such as chloroform, cyclohexane, and toluene, and the gas phase using Time Dependent-Density Functional Theory (TD-DFT) methods. In addition, Natural Orbital (NBO), Mulliken population analysis, and Molecular Electrostatic Potential (MEP) surface have been simulated to understand better the reactive sites in the molecular structures of safrole and isosafrole. The frontier molecular orbitals (FMO) energy gaps of safrole and isosafrole were simulated in polar and nonpolar solvents, confirming the safrole and isosafrole kinetic stability and chemical reactivity. The in-silico ADMET indices were utilized to ascertain the probable pharmacokinetic and biological features of safrole and isosafrole. A molecular docking investigation was also conducted to investigate the potential biological activity of safrole and isosafrole against the SARS-CoV-2 spike protein, providing more support for its antiviral efficacy.

The effect of the external electric field on the ground-state tautomerism in 8-(benzo[d]thiazol-2-yl)quinolin-7-ol has been studied by using density functional theory. The compound exists as an enol tautomer (off state) and under the influence of the external electric field a long-range intramolecular proton transfer can occur, placing the tautomeric proton at the quinolyl nitrogen atom (on state). This is a result of the much higher dipole moment of the end keto tautomer and indicates that the external electric field can be used to mimic the implicit solvent effect in tautomeric systems. In the excited state, the further stabilization of the most polar on state leads to a situation when the excited-state intramolecular proton transfer becomes impossible, limiting the intramolecular rotation to the conical intersection region.

In recent times, extensive research has been carried out to uncover effective drug treatments for coronavirus disease (COVID-19). The Carmofur (HCFU) molecule is primarily known for its antineoplastic properties and its use in cancer treatment. Nowadays, the antineoplastic drug Carmofur has shown its effectiveness in inhibiting the SARS-CoV-2 virus. The primary objective of this article is to utilize theoretical knowledge to explore the absorption mechanism and interaction between the HCFU molecule and the noble metal (Ag/Au/Pt)-loaded silica nanocomposites (HCFU + Ag/Au/Pt…SiO2). The optimized geometry, frequency, and intensity of the vibrational bands of the HCFU molecule and its complexes were obtained from the DFT method with the LANL2DZ basis set. The SERS technique was carried out to explore the adsorption of HCFU molecule with metal (Ag/Au/Pt)-loaded silica nanocomposites. The chemical reactivity and the charge distribution within the molecule were analysed with the help of HOMO-LUMO, Molecular Electrostatic Potential (MEP), Electron Localized Function (ELF), and Localized Orbital Locator (LOL) studies. The polar protic (ethanol, methanol, and water) and polar aprotic (DMSO) solvents were used to analyse the UV–Visible spectra of the molecules using the TD-DFT method. The drug-likeness properties of the molecules were calculated utilizing Lipinski’s rule, and finally, the molecular docking prediction was carried out for the Carmofur (HCFU) and its complexes with the selected proteins.

These days, the world is facing the threat of pandemic Coronavirus Disease 2019 (COVID-19). Although a vaccine has been found to combat the pandemic, it is essential to find drugs for an effective treatment method against this disease as soon as possible. In this study, electronic and thermodynamic properties, molecular electrostatic potential (MEP) analysis, and frontier molecular orbitals (FMOs) of nine different covid drugs were studied with Density Functional Theory (DFT). In addition, the relationship between the electronic structures of these drugs and their biological effectiveness was examined. All parameters were computed at the B3LYP/6-311++g(d,p) level. The Solvent effect was evaluated using conductor-like polarizable continuum model (CPCM) as the solvation model. It was observed that electrophilic indexes were important to understand the efficiencies of these drugs in COVID-19 disease. Paxlovid, hydroxyquinone, and nitazoxanide were found as the most thermodynamically stable molecules. Thermodynamic parameters also demonstrated that these drugs were more stable in the aqueous media. Global descriptors and the reactivity of these drugs were found to be related. Nitazoxanide molecule exhibited the highest dipole moment. The high dipole moments of drugs can cause hydrophilic interactions that increase their effectiveness in an aqueous solution.

In this work, 242 NMR spin–spin coupling constants (SSCC) in 20 molecules are calculated, either with correlated wave function methods, SOPPA and HRPA(D), or with density functional theory based on the B3LYP, BHandH, or PBE0 functionals. The calculations were carried out with and without treatment of solvation via a polarizable continuum model in both the geometry optimization step and/or the SSCC calculation, and thereby, four series of calculations were considered (the full-vacuum calculation, the full-solvent calculation, and the two cross combinations). The results were compared with experimental results measured in a solvent. With the goal of reproducing experimental values, we find that the performance of the PBE0 and BHandH SSCCs improves upon including solvation effects. On the other hand, the quality of the B3LYP SSCCs worsens with the inclusion of solvation. Solvation had almost no effect on the performance of the SOPPA and HRPA(D) calculations. We find that the PBE0-based calculations of the spin–spin coupling constants have the best agreement with the experimental data. [ABSTRACT FROM AUTHOR]

The spectroscopic, solvent effects, reactivity and MD simulations of N'-[(1E)-(2,6-dichlorophenyl-methylidene]adamantane-1-carbohydrazide (DMC) are reported. Solvation free energies of DMC in chloroform, ethanol and acetonitrile are −21.96, −24.39 and −12.31 kcal/mol and ethanol may be better for the solubilization. Electron donating and electron accepting powers are somewhat lower in solution, revealing a certain increase in the tendency to receiving electrons and a decrease in donate electrons in solution, except in acetonitrile, in which showed slightly higher values then in vacuum. ALIE surface show that regions where low energy is required to remove electrons are on benzene ring, chlorine atoms and N5. DMC is forming good contacts with protein's binding site residues and is important in the complex's stability showing antiviral activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • FT-IR, confocal Raman, UV–Vis and NMR spectra were used to investigate RO5263397. • Solvent effect of RO5263397 using DMSO and chloroform. • ELF and LOL studies utilized for visualising electron distribution. • HOMO- LUMO, MEP and Mulliken diagrams were depicted to estimate the reactive sites. • Molecular docking studies of RO5263397 with TAAR1, 5-HT 2c R and hAChE proteins. Density functional theory studies of TAAR1 (trace amine associated receptor 1) partial agonist RO5263397 carried out with precise and detailed spectroscopic investigation as well as validated experimentally. FT-IR, confocal Raman and UV–visible spectroscopic techniques were used to characterize the compound and corresponding theoretical calculations were carried out using DFT/B3LYP method with 6-311++G (d,p) basis set. Estimated and observed vibrational wavenumbers of the compound were assigned. UV–visible spectrum and FMOs (frontier molecular orbital) analysis reveals that the polarity affects the molecular reactivity and stability of the compound. Donor – acceptor interaction and second order perturbation energy have been explained using natural bond orbital analysis clarify the presence hydrogen bonds in the system. ELF and LOL studies visualises the localized and delocalized electrons in the title compound. RDG analysis evidences the various interactions present in the monomer and dimer of RO5263397. The structural importance of the compound were clearly examined using NMR spectral analysis. The existence of hydrogen bonding is validated by reactive site findings from Mulliken atomic charge distribution and molecule electrostatic potential surface studies. Information about distinct drug-receptor interactions obtained from molecular docking investigation offers the path of further study of molecular activity in various drug-receptor mechanism. [ABSTRACT FROM AUTHOR]

[Display omitted] • The highest bond length in the optimized structure was observed at 1.75 Å between C6-Cl8. • The solvent effect causes the HOMO-LUMO energy gap in the gas phase is lower (4.01 eV). • The experimental UV spectra well matched with theoretical spectra. • The titled compound showed good anticancer activity against MCF-7 cancer cell lines. • The titled compound exhibited the lowest binding energy of −5.77 kcal/mol. The Schiff base (E)-2-((4-chlorobenzylidene)amino)phenol (4CL2AM) has been synthesized from 4-chlorobenzaldehyde and 2-aminophenol. Spectroscopic techniques like FTIR, Raman, UV, fluorescence, and NMR were used to characterize the synthesized compound. The experimental data well matched with the DFT method (B3LYP/cc-pVDZ basis set). The frontier molecular orbital (FMO), molecular electrostatic potential (MEP), and electronic spectra (UV–visible) analysis were conducted on three different solvents such as gas, DMSO, and water. The frontier molecular orbital (FMO) analysis calculated the HOMO-LUMO energy gap as 4.0109 eV, 4.0406 eV, and 4.0411 eV for the gas phase, DMSO, and water respectively. Molecular electrostatic potential (MEP), localized orbital locator (LOL), and electron localize function (ELF) analysis revealed positions of localized and delocalized orbitals as well as electrophilic and nucleophilic attack sites. The natural bond orbital analysis (NBO) predicted highest stabilization energy was 33.37 kcal/mol. The locations of the covalent and non-covalent interactions were investigated by density overlaps region indicator (DORI), interaction region indicator (IRI), and noncovalent interaction (NCI) analysis. Drug likeness and ADME analysis were investigated. In vitro, anticancer activity studies revealed against MCF-7 breast cancer cell lines. In the molecular docking study, the predicted lowest binding energy is −5.77 kcal/mol for the 6NLV-4CL2AM system. [ABSTRACT FROM AUTHOR]

[Display omitted] • Theoretical calculations of Psilocin were performed at the B3LYP/6–311++G(d,p). • IEFPCM was used to account for solvent effects. • NCI between psilocin and solvent molecules were determined using AIM, RDG, ELF and LOL. • The effects of polar solvents on the structural parameters, Raman, IR, UV–Vis, FMO, MEP and NLO of psilocin were studied. Psilocin, or 4-HO-DMT (or 3-(2-dimethylaminoethyl)-1H-indol-4-ol), is a psychoactive alkaloid substance from the tryptamine family, isolated from Psilocybe mushrooms. This substance is being studied by various research groups because it has a clear therapeutic effect in certain dosages. In this work, the study of the structure and properties of psilocin was carried using theoretical methods: the effects of polar solvents (acetonitrile, dimethylsulfoxide, water, and tetrahydrofuran) on the structural parameters, spectroscopic properties (Raman, IR, and UV–Vis), frontier molecular orbital (FMO), molecular electrostatic potential (MEP) surface, and nonlinear optical parameters (NLO). Theoretical calculations were performed at the B3LYP/6–311++G(d,p) level by the density functional theory (DFT) method. IEFPCM was used to account for solvent effects. The types and nature of non-covalent interactions (NCI) between psilocin and solvent molecules were determined using Atoms in Molecules (AIM), the reduced density gradient method (RDG), the electron localization function (ELF), and the localization orbital locator (LOL). Experimental and calculated FT-IR, FT-Raman, and UV–Vis spectra were compared and found to be in good agreement. [ABSTRACT FROM AUTHOR]

A non-aqueous phase (Sb/Fe/NMP) desulfurization system for the removal of hydrogen sulfide from natural gas was constructed by introducing SbCl3 and FeCl3 in a specific ratio into N-methylpyrrolidone (NMP). The desulfurizing agent and its sulfur product were characterized, and the absorption pattern of H2S by the system was investigated by static desulfurization experiments. The results indicate that the desulfurizer's sulfur capacity can reach 16 g/L at room temperature and pressure, and that adding the optimum amount of water and appropriate temperature increase can assist to increase desulfurization efficiency. The system maintained a sulfur capacity level of more than 90% of the initial sulfur capacity after five consecutive desulfurization-regeneration cycles. XRD and XPS spectrogram revealed that the regenerated solid product was high purity sulfur. Sb3+ is a key component to ensure the effective absorption of H2S. The presence of a moderate amount of Fe3+ can oxidize and absorb small amounts of H2S and promote the oxidative regeneration of the system. In addition, we combined the obtained experimental data with density flooding theory (DFT) theoretical calculations to show that the effective coordination of Sb(III) with HS− in the NMP environment is the main reason for the effective absorption of H2S by the desulfurizer. NMP is not involved in the coordination absorption process of hydrogen sulfide. [ABSTRACT FROM AUTHOR]

In the present research, the cation–π interactions in acetaminophen-M complexes (M = Mn+, Fe2+, Co+, Ni2+, and Cu+) are investigated using density functional theory (DFT/ωB97XD) in the gas phase and solution. The results show that the absolute values of energy are reduced in going from the gas phase to the solution. Based on the obtained data, the complexes in water are the most stable. The natural bond orbital (NBO) and the atoms in molecules (AIM) analyses are also applied to achieve more details about the nature of interactions. These results are useful for understanding the role of the drug-receptor interactions in the complexes. According to AIM outcomes, the cation–π interactions are the closed-shell and may indicate the partially covalent nature in the complexes. A comprehensive analysis is also performed on the conceptual DFT parameters of the complexes to evaluate their electronic properties. Our findings show increasing the stability and decreasing the reactivity of the complexes in the solution phase with respect to the gas phase. These interactions are ubiquitous in biological systems, and their importance in theoretical models led us to study such important interactions. The results of this study may be useful for the design and synthesis of a variety of supramolecular complexes with the desired properties. [ABSTRACT FROM AUTHOR]

The structural and antioxidant activity of two flavonols, namely, Fisetin and Robinetin, have been investigated employing the density functional theory (DFT) using B3LYP functional and 6–311++G (d, p) basis set. The calculations were performed in the gas phase and under the solvent effect of water, dimethylsulfoxide (DMSO), methanol, and benzene. The hydrogen-atom transfer (HAT), single electron transfer followed by proton transfer (SET-PT), and sequential proton loss electron transfer (SPLET) mechanisms were investigated to rationalize the radical scavenging capacities and to identify the favored antioxidant mechanism. Hence, the bond dissociation enthalpies (BDE) ionization potential (IP), IE, proton dissociation enthalpy (PDE), proton affinity (PA), and electron transfer enthalpy (ETE) related to each mechanism were reported and discussed in function of the solvent effect. For both flavonols, the results showed that 4′-OH hydroxyl is the preferred active site following the trend 4′-OH > 3′-OH > 3-OH > (5′-OH) > 7-OH. Besides, the HAT mechanism is energetically the most favored pathway. The energetically favored solvents follow the trends water > DMSO > benzene > methanol and benzene > DMSO > methanol > water, for Fisetin and Robinetin, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • B 9 N 9 nanoring was examined as nitrobenzene (NB) sensor using DFT. • The pristine B 9 N 9 can serve as an electronic and φ-type sensor for NB molecule. • The pristine B 9 N 9 nanoring can be utilized as an effective NB sensor. • The Sc decorated B 9 N 9 nanoring can be used for NB removal from the environment. Nitrobenzene (NB), an aromatic organic compound widely used in various industries, has several environmental risks. Due to its risks, reliable sensing mechanisms are crucial. In the present work, we investigated the potential of the pristine and Sc decorated B 9 N 9 nanoring as a sensor for detection of the toxic NB molecule using density functional theory (DFT). We have analyzed the structural parameters, adsorption energy (E ad), highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), HOMO-LUMO gap, density of states (DOS) spectra, Mulliken charge transfer, dipole moment, IR spectra, non-covalent interactions (NCI) iso-surfaces, recovery time (τ) and work function (φ) before and after the adsorption of NB onto pristine and Sc decorated B 9 N 9 nanorings. Our analysis revealed that the NB interacted optimally with the pristine B 9 N 9 nanoring, as evidenced by changes in electronic properties and E ad value of −0.58 eV. However, the Sc decorated B 9 N 9 nanoring indicated a strong interaction with NB with E ad of −4.09 eV at a proximal distance of 2.12 Å. Furthermore, our study demonstrated that the pristine B 9 N 9 nanoring could be used as both an "electronic sensor" and "φ-type sensor". Additionally, to esteem rapid recovery for practical feasibility, we calculated τ for both the pristine and Sc decorated B 9 N 9 nanoring. The short τ of the pristine nanoring indicates its suitability as NB sensor. In contrast, the longer τ of the Sc decorated nanoring suggests its applicability for NB storage or its removal from the surroundings. Overall, our findings underscore the potential of pristine B 9 N 9 nanoring as effective NB sensor and removal. We hope that our study will assist experimentalists to develope a reliable B 9 N 9 nanoring based sensor for the detection of NB molecules. [ABSTRACT FROM AUTHOR]

These days, the world is facing the threat of pandemic Coronavirus Disease 2019 (COVID-19). Although a vaccine has been found to combat the pandemic, it is essential to find drugs for an effective treatment method against this disease as soon as possible. In this study, electronic and thermodynamic properties, molecular electrostatic potential (MEP) analysis, and frontier molecular orbitals (FMOs) of nine different covid drugs were studied with Density Functional Theory (DFT). In addition, the relationship between the electronic structures of these drugs and their biological effectiveness was examined. All parameters were computed at the B3LYP/6-311++g(d,p) level. The Solvent effect was evaluated using conductor-like polarizable continuum model (CPCM) as the solvation model. It was observed that electrophilic indexes were important to understand the efficiencies of these drugs in COVID-19 disease. Paxlovid, hydroxyquinone, and nitazoxanide were found as the most thermodynamically stable molecules. Thermodynamic parameters also demonstrated that these drugs were more stable in the aqueous media. Global descriptors and the reactivity of these drugs were found to be related. Nitazoxanide molecule exhibited the highest dipole moment. The high dipole moments of drugs can cause hydrophilic interactions that increase their effectiveness in an aqueous solution. [ABSTRACT FROM AUTHOR]

The solvent effect on the molecular properties of lawsone and purpurin molecules has been investigated using DFT and TD-DFT. The calculations have been performed using CAM-B3LYP functional and 6-311++G(d,p) basis set. Molecular properties including solute energy, electronic spatial extent, HOMO–LUMO energy gap, thermodynamic properties, the free energy of solvation, electronic properties and UV–visible spectra have been studied. These properties have been analysed in 12 solvents, i.e. benzene, chloroform, aniline, dichloromethane, dichloroethane, benzyl alcohol, 3-pentanone, acetone, ethanol, methanol, acetonitrile and DMSO, and the variation of molecular properties has been studied as a function of the dielectric constant of solvents. We also studied the light-harvesting efficiency (LHE) and the lifetime of excitation of dye molecules in the presence of selected solvents to identify its use as a sensitizer in dye-sensitised solar cells. It has been found that purpurin molecule exhibits a higher LHE and lower excited state lifetime than lawsone molecule. We also observed that the LHE of lawsone molecule has a maximum value for aniline and benzyl alcohol solvents, whereas for purpurin molecule, aniline shows greater LHE values due to the auxochrome effect. [ABSTRACT FROM AUTHOR]

In this work, 242 NMR spin–spin coupling constants (SSCC) in 20 molecules are calculated, either with correlated wave function methods, SOPPA and HRPA(D), or with density functional theory based on the B3LYP, BHandH, or PBE0 functionals. The calculations were carried out with and without treatment of solvation via a polarizable continuum model in both the geometry optimization step and/or the SSCC calculation, and thereby, four series of calculations were considered (the full-vacuum calculation, the full-solvent calculation, and the two cross combinations). The results were compared with experimental results measured in a solvent. With the goal of reproducing experimental values, we find that the performance of the PBE0 and BHandH SSCCs improves upon including solvation effects. On the other hand, the quality of the B3LYP SSCCs worsens with the inclusion of solvation. Solvation had almost no effect on the performance of the SOPPA and HRPA(D) calculations. We find that the PBE0-based calculations of the spin–spin coupling constants have the best agreement with the experimental data.

This work provides new insight into assembling of phenol in various solvents and competition between different kinds of interactions. To examine both weak and strong interactions, we selected a series of non-aromatic and aromatic solvents. Infrared spectra were measured at low (0.05 M) and high (2 M) phenol content. In addition, we performed density functional theory calculations of the structures and harmonic vibrational spectra of 1:1 complexes of phenol with the solvents and the associates of phenol from dimer to tetramer. Based on these results, we divided the solvents into three groups. The first group consists of non-aromatic solvents weakly interacting with phenol. Depending on the concentration, molecules of phenol in these solvents remain non-bonded or self-associated. In diluted solutions of phenol in chlorinated non-aromatic solvents do not appear free OH groups, since they are involved in a weak OH···Cl interaction. It is of note that in diluted solutions of phenol in tetramethyl ethylene both the non-bonded and bonded OH coexists due to solvent–solvent interactions. The second group consists of aromatic solvents with methyl or chlorine substituents. At low concentration, the molecules of phenol are involved in the phenol–solvent OH···π interaction and the strength of these interactions depends on the solvent properties. At a higher phenol content an equilibrium exists between phenol–solvent OH···π and phenol–phenol OH···OH interactions. Finally, the third group includes the aromatic and non-aromatic solvents with highly polar group (C≡N). In these solvents, regardless of the concentration all molecules of phenol are involved in the solute–solvent OH···NC interaction. Comparison of the experimental and theoretical band parameters reveals that molecules of phenol in non-aromatic solvents prefer the cyclic associates, while in the aromatic solvents they tend to form the linear associates. Graphical Abstract [ABSTRACT FROM AUTHOR]

The various tautomers and conformers of SLC-0111, a well-known biologically potent compound, have been investigated using density functional theory (DFT) calculations in the gas phase and aqueous solution. The amide form is found to be the only stable tautomeric form in both the phases, with the trans-cis conformer as the most stable structure in the gas phase and the trans-trans conformer in aqueous solution. The deprotonation of the sulfonamide nitrogen leading to the formation of the SLC-0111 anion occurs at pH > 10. The various intramolecular interactions and reactivity of the molecule have been characterized using natural bond orbital (NBO) analysis and calculation of global reactivity parameters. The effect of the solvent polarity on the energies and nature of the frontier molecular orbitals has been investigated for both the neutral and anionic forms. Further, the electronic spectra and vibrational spectra of both the states have also been computed and the effect of changing solvents on the electronic spectra has been investigated. The calculated nonlinear optical (NLO) properties of the molecule show that the molecule has potential to be featured as an NLO material. [ABSTRACT FROM AUTHOR]

• Geometry optimization of the molecules have been carried out using DFT. • FT-IR and FT-Raman techniques combined with DFT calculations. • HOMO–LUMO, NBO, MEP, ELF and LOL study has been performed. • UV–vis study predicted the electronic excitations by using TD-DFT method. • Molecular docking with proteins upholds anti-tubercular activity. In this study an isatin derivative (E)-5-nitro-3-(phenylimino) indolin-2-one (5NPI) has been synthesized and examined utilizing quantum chemical calculations of DFT approach for structural optimization, electronic and vibrational characteristics. Functional groups have been detected using FT-IR spectra and compared with simulated spectra. To model UV–vis absorption and identify electronic characteristics in solvents and gas phase, TD-DFT computations have been performed. The GIAO technique was used to measure chemical shifting in NMR in several different solvents. Theoretical parameters coincide perfectly with experimental data. HOMO and LUMO band gaps reflect chemical activity and have satisfactory charge exchange inside the molecule. RDG analysis, topological and NBO investigations have been used to study weak intermolecular interactions. Reactive regions of the 5NPI compound have been determined using MEP and Fukui functions. NLO behavior has been computed using hyperpolarizability parameters. The anticancer activities of the compound 5NPI were evaluated from the National Cancer Institute (NCI), USA and subjected to in-silico analysis such as drug-likeness, ADMET and molecular docking. The compound 5NPI has been docked with 3RUX, 8ADA, 3TFU and 6TOJ proteins and showed moderate binding affinity as −7.14, −6.42, −6.68 and −8.41 kcal/mol respectively. Compound 5NPI is used as a lead molecule in the treatment of TB along with various tumors. [ABSTRACT FROM AUTHOR]

2,3-dimetoksifenil boronik asit molekülünün (2,3-dmpba; C6H3(OCH3)2B(OH)2) konformasyonel yapısı ve hidroksil (OH) gerilmeleri titreşimi üzerindeki çözücü etkisi Fourier dönüşümlü kızılötesi spektroskopisi (FTIR) ve yoğunluk fonksiyonel teorisi (YFT) ile birlikte hem deneysel hem de teorik olarak araştırılmıştır. Hesaplamalar polarize süreklilik modeli (PCM) kullanılarak on sekiz farklı organik çözücüde ve bileşiğin dört konformasyonel izomeri üzerinde odaklanmıştır. Titreşim analizleri için skalanmış kuantum mekanik model (SQM) kullanılmıştır. Ele alınan molekülün en kararlı konformasyonel izomeri çözücü etkisinden bağımsızdır. SQM metodu titreşim frekansları üzerindeki çözücü etkisini belirlemede oldukça başarılıdır. Bu çalışmadan elde edilen deneysel ve teorik tüm bulgular fenil boronik asit türevlerinin yapısal karakteristiklerini anlamada faydalı olacaktır.

The experimental and theoretical investigations of solvent effect on conformational structure and the hydroxyl stretching vibration of 2,3-dimethoxyphenylboronic acid (2,3-dmpba; C6H3(OCH3)2B(OH)2) molecule were studied by Fourier transform infrared (FTIR) spectroscopy and density functional theory (DFT). Calculations were performed by four conformational isomers of the title compound in eighteen different organic solvents by the polarizable continuum model (PCM). Scaled quantum mechanical (SQM) method was performed for the vibrational analysis. Most stable conformational isomer of the compound is independent of the solvent effect. Results of SQM method are very successful in determining the solvent effect on vibrational frequency. Experimental and theoretical findings from the present search will be useful to understand structural characteristics of phenylboronic acid derivatives.

We investigate the rich stereochemistry of cocaine and its diastereoisomers from a theoretical perspective using density functional theory. The relative stability of the eight considered isomers is discussed, and a comparison of the corresponding internal coordinates is given. Our results reveal that the S-pseudococaine isomer is the most stable conformation, whereas the natural occurring isomer (R-cocaine) lies higher in energy. The different isomers' chemical reactivity is discussed based on the calculation of the hardness, softness, electrophilicity and dipole moment. It was found that the dipole moment varies over a broad range from 0.65 to 4.60 D, whereas the other properties are slightly modified. The solvent effect on the energy stability of the cocaine isomers was studied by considering chloroform, dimethyl-sulfoxide (DMSO) and water as implicit solvents. Our calculations show that the different isomers' energy order and their energy gaps are slightly modified due to solvent effects. However, in all cases, the S-pseudococaine remains the most stable isomer. However, the dipole moment and the chemical reactivity of the cocaine isomers increase with the solvent polarity. [ABSTRACT FROM AUTHOR]

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It was well known that solvent effect plays a very important role in the catalytic reaction. There are many theoretical studies on the solvent effect in homogeneous catalysis while there are few theoretical studies on the solvent effect in the heterogeneous catalytic reaction and there has been no work to investigate the solvent effect on furfural transformation in heterogeneous catalysis. In the present work, both the density functional calculations and the microkinetic analysis were performed to study the selective hydrogenation of furfural over Pt(111) in the presence of methanol as well as toluene and compared with that in the gas condition. The present results indicated that the methanol can enhance the adsorption strength of furfural and other oxygen-containing reaction species due to its relatively strong polarity properties and this can be a main reason for solvent-induced high activity and selectivity. Another reason is that reaction paths study showed that the presence of methanol solvent makes the dehydrogenation of furfural less thermochemical due to the fact that furfural is more stabilized than that of dehydrogenation species, and methanol also has an inhibition effect on the dehydrogenation of furfural in the kinetic aspect, and further energetic span theory proves highest activity and selectivity for hydrogenation in methanol solvent of vapor, methanol and toluene. Moreover, microkinetic model simulation demonstrated that the activity and selectivity of hydrogenation in methanol is both higher than that in vapor and toluene. The much higher activity in methanol is due to the stabilized adsorbed reactants in the surface, which leads to a higher surface coverage of furfural. It might be proposed based on the present work that a solvent with relatively strong polarity may be favorable for the high selective hydrogenation of furfural. • DFT was used to study the effect of solvent on furfural hydrogenation over Pt(111). • CH 3 OH can enhance the adsorption of furfural and other oxygen-containing species. • CH 3 OH makes furfural hydrogenation more favorable than that in vapor and toluene. [ABSTRACT FROM AUTHOR]

The title compound was synthesized by ring-closure reaction of thiophene-2-carbohydrazide with benzyl isothiocyanate and characterized using spectroscopic methods (NMR and FT-IR). Quantum chemical calculations at the B3LYP/6-311++G(d,p) level were carried out to examine its molecular and spectroscopic properties, thione–thiol tautomerism, and proton transfer reaction. The structural and spectroscopic results were well consistent with the experimental data. The solvent effect on the proton transfer reaction was examined using three solvents (acetone, ethanol, and dimethyl sulfoxide) through the polarizable continuum model (PCM) approximation (direct solvent effect) and solvent-assisted mechanism. A high energy barrier was determined for the interconversion of the thione and thiol forms in both gas and solution phases. Even though the presence of solvent molecules significantly reduced the barrier to proton transfer, it was insufficient for the reaction to occur. The corresponding thermodynamic parameters and the energy difference between the HOMO and LUMO of the thione and thiol tautomers were calculated. [ABSTRACT FROM AUTHOR]

Echinatin (Ech), a characteristic retrochalcone isolated from liquorice, a widely used herbal medicine, has been investigated in detail in terms of its conformational and electronic properties in different dielectric media using density functional calculations. Natural bond orbital (NBO) analysis suggests an extended conjugation in the molecule, including a keto-ethylenic group (–CO–CH=CH–) connecting both the rings. The aromaticity of Ech has been studied using the nucleus-independent chemical shift (NICS) method. The acidity constants (pKa) have been simulated for both the hydroxyl groups in the molecule. Molecular electrostatic potentials (MEPs) have been computed to predict the reactivity of Ech toward both electrophiles and nucleophiles. Further, the electronic spectra of the neutral and deprotonated states have been computed in different solvents using an implicit solvation model, SMD. The vibrational spectra of both the neutral and anionic forms have also been simulated. Besides these, 1H-NMR and 13C-NMR spectra have been computed and compared with the experimental values. In addition, the frontier molecular orbital (FMO) energies, a number of global reactivity descriptors, viz., chemical hardness (η), chemical potential (μ), global softness (S), global electrophilicity (ω), and nucleophilicity (N) indices and various thermodynamic parameters have also been calculated in order to get a better insight into the molecular properties. [ABSTRACT FROM AUTHOR]

We report a protocol for the evaluation of theoretical half-wave potential (E1/2) using a set of 22 mixed chelate copper (II) complexes containing 1,10-phenanthroline and 2,2′-bipyridine derivatives as primary ligands, and acetylacetonate or glycinate as secondary ligands (formally from the Casiopeínas® family) for which accurate experimental values were determined in a 2/5 mixture of ethanol/water. We have calibrated the BP86, PBE, PBE0, B3LYP, M06-2X, and ω-B97XD functionals, using the Los Alamos LANL2DZ and Stuttgart-Köln SDDAll effective core potentials for the Cu and Fe atoms and the 6-311+G* basis set for the C, H, O, and N atoms. To address the solvent effects, we have saturated the first solvation shell with up to 9 water molecules for the explicit model and compared it with the Continuum Like-Polarizable Continuum Model (CPCM) implicit solvent scheme. We found that the PBE/LANL2DZ-6-311+G* protocol (with the CPCM implicit solvent scheme with an effective dielectric constant ε = 64.9121 for the 2/5 mixture of ethanol/water) yields the overall best performance. The theoretical values are compared with experimental data, three of which are reported here for the first time. We find good correlations between the theoretical and experimental E1/2 values for the 2,2′-bipyridine derivatives (R2 = 0.987, MAE = 86 mV) and 1,10-phenanthroline derivatives (R2 = 0.802, MAE = 58.4 mV). The correlation trends have been explained in terms of the copper atom's ability to be reduced in the presence of the ligands. The Gibbs free energy differences at 298 K obtained for the redox reactions show that the more flexible secondary ligands (acetylacetonate) lead to larger entropic contributions which, as expected, increase the average MAE values as compared with the more rigid ligands (glycine). The present protocol yields lower MAEs as compared with previous approaches for similar mixed and flexible Cu(II) complexes. [ABSTRACT FROM AUTHOR]

Density functional theory investigations at the DFT-B3LYP/6-311++G** theoretical level employed to determine the tautomerism, substituent effects of 4-substituted 4-amino-5-methyl-2,4-dihydro-3H-1,2,4-triazole-3-thione, and its derivatives (4-R-H, 4-R-CH3, 4-R-F, 4-R-NO2) in the selected solvent (acetone, acetonitrile, and dichloromethane) and gas phases using the polarizable continuum method (PCM) model. The substituted 1,2,4-triazoles have two main different tautomers namely N2-H and S7-H. For considered derivatives, thione forms are more energetically stable and dominant form in the studied solvent and gas phases. In addition, geometrical parameters, charges on atoms, dipole moments, energetic properties, and the nucleus-independent chemical shifts (NICS) are investigated. It has been seen that these molecular features of the studied compound and its derivatives are mostly solvent dependent. For electron-releasing and -withdrawing derivatives in the solution and gas phases, 2-H forms are the more stable and dominant form. The relative stability of the C4-substituted 1,2,4-triazole tautomerism is influenced by the possibility for intramolecular interactions between substituent and electron-donor or electron-acceptor centers of the triazole ring. [ABSTRACT FROM AUTHOR]

[Display omitted] • Aromatic sidechains provide additional stabilisation of hydrogen-bonded complexes. • The solvent effect is the main factor that distinguishes formation constants in PCA. • Theory predicts a greater impact of resonance than experimentally observed. • Surface area, partial charge and inductive descriptors show the best correlation. In this research, experimental and theoretical spectral analysis of N -monosubstituted benzamides was performed by mid-infrared spectroscopy and density functional theory. The MIR spectroscopic characteristics for N–H∙∙∙O, N–H∙∙∙N and N–H∙∙∙π hydrogen-bonded complexes and also the equilibrium constants for 1:1 complex formation are given. The structures of selected N -substituted benzamides (as proton donors), benzene, acetonitrile, and tetrahydrofuran (as proton acceptors), as well as their complexes, were optimised at the M06-2X/6–311++G(d,p) level of theory. The solvent effect on hydrogen-bonded complexes and the correlations between the equilibrium constants and molecular descriptors of N -monosubstituted benzamides were also investigated using a principal component analysis. [ABSTRACT FROM AUTHOR]

In the present study, siderol acetate (1) was synthesized from siderol isolated from endemic Sideritis species, then its chemical structure was determined by using various spectroscopic methods (FT-IR, 1H NMR, and 13C NMR). The geometrical parameters, vibrational frequencies and gauge including atomic orbital (GIAO) 1H and 13C NMR chemical shift values for siderol acetate in the ground state have been calculated using the Density Functional Theory (DFT) and Hartree–Fock (HF) methods with the 6-31G(d) basis set. The calculated vibrational frequencies and 1H and 13C NMR chemical shifts have been compared with experimental values. A combined study based on NMR data and quantum-mechanical calculations using DFT/GIAO indicate that 1 is the correct structure of the title molecule. [ABSTRACT FROM AUTHOR]

A detailed quantum chemical study of the solvent effects in the intramolecular hydrogen bonding, conformational stability, and reactivity of aspirin has been performed using density functional theory (DFT) at the B3LYP/6‐31G(d) theory level. Seven conformational isomers, three of them presenting intramolecular hydrogen bonds, have been located. Thermochemical functions have been computed, and relative energies and free enthalpies have been determined in gas and aqueous phases. Several molecular properties have been calculated to predict the ability of aspirin to acylate cyclooxygenase (COX) enzymes. A six‐membered‐ring hydrogen‐bonded conformer was found to be the most reactive species. The solvation in aqueous phase increases the reactivity and strengthens intramolecular hydrogen bonding. [ABSTRACT FROM AUTHOR]

The experimental and theoretical investigations of solvent effect on conformational structure and the hydroxyl stretching vibration of 2,3-dimethoxyphenylboronic acid (2,3-dmpba; C6H3(OCH3)2B(OH)2) molecule were studied by Fourier transform infrared (FTIR) spectroscopy and density functional theory (DFT). Calculations were performed by four conformational isomers of the title compound in eighteen different organic solvents by the polarizable continuum model (PCM). Scaled quantum mechanical (SQM) method was performed for the vibrational analysis. Most stable conformational isomer of the compound is independent of the solvent effect. Results of SQM method are very successful in determining the solvent effect on vibrational frequency. Experimental and theoretical findings from the present search will be useful to understand structural characteristics of phenylboronic acid derivatives. [ABSTRACT FROM AUTHOR]

• Geometry optimization of the molecule have been carried out.. • Complete vibrational analysis of the title compound is carried out. • HOMO–LUMO, NBO, MEP, ELF and LOL study has been theoretically performed. • UV–Vis study predicted the electronic excitations by using TD-DFT method. • Molecular docking study revealed the bioactivity of the molecule. Herein, one-pot synthesis of (E)-5-bromo-3-(phenylimino)indolin-2-one (5BPI molecule), density function theory for validation of the synthesized molecule, and biological activities, have been reported. Anticancer activity of the synthesized (E)-5-bromo-3-(phenylimino)indolin-2-one compound from National Cancer Institute, USA, was evaluated. However, antimicrobial nature of the molecule against 1NCO, 7C2N, 3DRA, and 4YNU proteins was also demonstrated using molecular docking as a preliminary investigation that showed the binding with ligand possess very low binding affinity as −6.22, −6.51, −5.59, and −7.45 kcal/mol, respectively. Density Functional Theory was effectively used to analyse the stability of the molecular structure under optimized circumstances, for comparative studies involving experimental and theoretical data for the gas and solvent phases. According to this analysis, UV–Vis spectra, band gap energy, nonlinear optical properties, molecular electrostatic potential, electron localization function, localized orbital locator, and reduced density gradient were illustrated in different solvents. In addition, natural bond orbital analysis was conveyed to the largest second-order perturbation energy that corresponded to electron delocalization from the donor and acceptor interaction. As a consequence, it was clearly demonstrated by the compound's drug-likeness, ADMET characteristics, docked complexes' released energies, and anticancer activity that it may be employed as a lead molecule to treat different carcinomas after the more potent alterations in their skeleton prompted by chemical reactions. [ABSTRACT FROM AUTHOR]

Halogen and solvent influence on the conformational stability and carbonyl stretching vibration of 5-Halogeno-2-thiophenecarboxaldehydes (C5H3XOS; X=F, Cl or Br) were investigated by the density functional theory using the B3LYP functional, 6-311+G(3df,p) basis set and polarizable continuum model. Calculations were performed by the cis and trans forms of the compounds in eighteen different solvents. The carbonyl stretching frequencies were correlated with some solvent parameters such as the Kirkwood-Bauer-Magat equation, the solvent acceptor number, Swain parameters and the linear solvation energy relationships. The findings of this research will be useful for thiophenecarboxaldehydes.