Condensed Fukui Function Research Articles

Nucleophilic reactions with the novel 7-(chromon-3-yl)quinolino [3′,4′:5,6] pyrano[3,2-c]quinoline: Synthesis, biological and computational studies

Condensation reaction of 3-formylchromone (1) with 1-ethyl-4-hydroxyquinolin-2(1H)-one (2) in glacial acetic acid afforded the condensation product 4; in 1:2 molar ratio. Compound 4 was used as precursor for construction of some propenones linked pentacyclic quinolinopyranoquinoline. Ring opening of chromone moiety in compound 4 was achieved via reactions with a diversity of primary amines leading to propenone derivatives 5–7 and 11–13 in good yields (62–73%). All propanone derivatives exist in the E-configuration as deduced from their 1H NMR spectra. DFT/B3LYP functional was used with 6–311+G(d,p) basis sets for all theoretical calculations. Based on optimized geometry, the chemical potential (Pi), electronegativity (χ), hardness (η) and electrophilicity index (ω) are some of the global reactivity descriptors that were computed to predict the chemical reactivity of the studied compounds; where compound 13 has the highest softness and electrophilicity index (ω). Moreover, to determine the relative stability of compounds 1–4, the thermodynamic parameters such as enthalpy and free energies of the reactions were computed; where compound 4 has the lowest free energy of reaction (-439.61 kcal/mol), so its formation is spontaneous. By utilizing molecular electrostatic potential (MEP) and local-based descriptors in the form of condensed Fukui functions of the starting compound 4, the susceptible sites for electrophilic and nucleophilic attack were investigated. For compound 4, fk+ and Δfk values are more positive at C9 and C7 than other sites and these sites have more electrophilic characters. Therefore, nucleophilic attacks began at C9. On the other hand, the GIAO approximation was used to compute the 1H and 13C NMR chemical shift values in the ground state, of the present compounds, where a good agreement was observed between experimental and theoretical chemical shift results. Further, the calculated first hyperpolarizability of prepared compounds are found to be greater than that of urea. So, these compounds are ideal candidates for non-linear optical applications. The synthesized compounds were screened for their antimicrobial and anticancer activities showing variable inhibitory action. Compounds 5, 7 and 13 were more effective antimicrobial candidates against all tested microorganisms, while compound 13 was the most active against HepG-2 cell lines. Furthermore, a quantitative structure–activity relationship (QSAR) (relationship between DFT calculated descriptors and biological activities pIC50) model was built by applying multiple linear regression (MLR) on the synthesized compounds as anticancer agents. Moreover, Lipinski's rule of five indicates no problems with oral bioavailability of the prepared compounds.

Effect of different solvents, molecular level vibrational energies, electronic, electrostatic, donar-acceptor and pharmaceutical studies on 3-methoxy phenyl acetonitrile- anti depressant agent

The most economical method for analyzing molecular structure is density functional theory (DFT), which has several applications in the study of vibrational spectrum biological systems. In the context of biological in addition to NLO behavior, the density functional theory (DFT) technique has numerous purposes. It turned out to be the most financially sound approach for examining molecular geometry. 3-Methoxy phenyl acetonitrile (3MPAN) has been optimized and its skeletal parameters were computed using the basis function 6–311++ G(d,p). HOMO and LUMO analytics have been used to determine the transfer of charge within the molecule. By detecting internal charge transfer, hyperconjugation, and stabilization energy, the NBO research has been used to confirm the molecule's stability. Mulliken's charges and molecular electrostatic potential were thoroughly investigated utilizing DFT techniques. B3LYP basis functionals were used to look at the NLO properties of the drug molecule. Condensed Fukui functions and global descriptors have been extensively used to study the reactive sites and reactivity of the pharmacological molecule. 29.85 Kcal/mol equilibrium energy is the greatest one occurred between O1 of LP(2) to π*(C5-C8). In order to investigate solvation analysis, various solvents were used. Solvents drastically altered the molecule's global characteristics and structural reactivity. Compared to other sol-vents, methonal has the largest band gap value of 5.619 eV. The substance under study has extraordinary NLO (non-linear optical) characteristics. For both the gas phases and solvents, ELF, LOL and RDG were stimulated. Although and drug-likeness were used to support the bioactivities. The fact that this chemical adheres to five Lipinski's rule means therefore, ingesting effective dose of similar compounds should not pose an issue. The results of docking studies demonstrated the effectiveness of the ligand under research as an anti-depressant medication.

Degradation of bisphenol A, bisphenol S, and bisphenol AF in the UV-LED/chlorine reaction: Effect of pH on the kinetics, transformation products, and degradation pathway

We investigated the UV-LED/chlorine reaction for the degradation of bisphenol A (BPA) and its alternatives, bisphenol S (BPS) and bisphenol AF (BPAF) in water. Three bisphenols (BPs) were removed by the pseudo-first-order kinetics. BPA showed the highest removal compared to BPS and BPAF at pH 7 due to the electron-donating isopropyl group in BPA compared to electron-withdrawing sulfonyl and hexafluoro-isopropyl groups in BPS and BPAF, respectively. While the degradation of BPs during the UV-LED/chlorine reaction was contributed mainly by reactive chlorine species (RCS) at pH 6 to 8, and mainly by chlorination reaction at pH 9 due to the different functional groups and pKa values of BPs, and the status of chlorine depending on pHs. While humic acid suppressed the degradation of BPs, HCO3− ions generally increased the removal of BPs. Chlorinated BPs (ClxBPs) were identified as major transformation products (TPs) in the UV-LED/chlorine reaction using LC-QTOF/MS analysis, and these ClxBPs were effectively removed by further reaction. In addition, >15 minor TPs and three mineralization products (acetate, formate, and chloroform) were identified for each BP degradation. Defluorination (37% in 4 hr) was observed an as the mineralization pathway for BPAF, indicating that UV-LED/chlorine reaction can break the strong C-F bond on BPAF. We proposed the degradation pathways of three BPs based on the identified TPs and theoretical reactive sites calculated using the condensed Fukui function. The major pathways were sequential chlorine substitution, coupling reaction, and hydroxylation reaction. The ECOSAR assessment showed that the UV-LED/chlorine process is effective in lowering the ecotoxicities of BPs and their TPs.

A novel solar-activated chlorine dioxide process for atrazine degradation in drinking water

New technologies using advanced oxidation processes (AOPs) with low energy-input to address the presence of micro-contaminants and the formation of disinfection byproducts (DBPs) are required for drinking water safety. In this work, the activation of chlorine dioxide with solar (solar/ClO2 process), a type of renewable and inexhaustible energy, was developed to degrade atrazine (ATZ) and control the formation of DBPs. Results revealed that solar/ClO2 process was effective in degrading ATZ. Hydroxyl radicals (•OH) and chlorine radicals (Cl•) produced in solar/ClO2 process were found to be the predominant agents for ATZ degradation with contribution rates of 55.9% and 44.1%, respectively, based on radical quenching tests and competition kinetics. Reaction pH did not affect the total amount of Cl• and •OH (i.e., [•OH]exp) and [Cl•]exp), while the conversion of Cl• to •OH was responsible for the depressed ATZ degradation efficiency with the increasing pH in solar/ClO2 process. The presence of bicarbonate (HCO3−), chloride (Cl−) and humic acid (HA) retarded the ATZ degradation mainly due to they decreased [•OH]exp) and [Cl•]exp. Using the UPLC-MS/MS analysis, six degradation intermediates of ATZ were tentatively identified, and the three-stage degradation pathway as well as the stepwise detoxification of ATZ were confirmed by the condensed Fukui function (CFF) calculation and ECOSAR prediction. Applying solar/ClO2 as a pretreatment of HA-containing water, the formation of DBPs during post-chlorination was significantly reduced. However, the presence of ATZ during solar/ClO2 pretreatment of HA significantly lowered the control efficiency of DBPs. The major degradation intermediate, i.e., deethyldeisopropylhydroxyatrazine (DEIHA), of ATZ could incorporate into HA and therefore providing more precursors for DBPs. The acute toxicity recorded by the behavior of zebrafish larvae revealed that using chloramine instead of chlorine downstream the solar/ClO2 pretreatment of ATZ and HA could significantly reduce the acute toxicity by decreasing the formation of total DBPs. This study demonstrated the great potential of applying solar/ClO2 process followed by chloramination to simultaneously degrade micro-contaminants and reduce DBPs formation as well as toxic risk in practical applications.

Syntheses, DFT studies and comparatively photovoltaic applications of some pyrene-imine hybrid derivatives

In this study, (E)-N-phenyl-1(pyren-1yl)methanimine (3) and a isomeric mixture of 5ZZ and 5EE (1,4-phenylenebis(1-(pyren-1-yl)methanimine) were synthesized by condensation of pyrene-1-carbaldehyde (1) with aniline (2) or benzene-1,4-diamine (4) The synthesized compounds were characterized using NMR, UV–vis, IR and HRMS spectroscopic techniques.Utilizing the density functional theory (DFT) and a basis set of B3LYP/6-311G(2d,2p), theoretical computations were done. The computed values were applied to simulated spectra of compounds 3 and the isomeric mixtures 5EE, and 5ZZ demonstrating good agreement with observed spectra. In various solvents, the UV–vis spectra of compounds 3, 5EE, and 5ZZ were recorded in areas 200–500 nm, and function density theory (DFT) and time-dependent density functional theory (TD-DFT) algorithms were used to determine if they can serve as metal-free organic dyes in the use of dye-sensitized solar cells (DSSCs). The charge separation distance (Δr) between an electron and the hole it corresponds to was investigated in addition to the degree of electron-hole overlap (Λ) because transition density matrices (TDM) give information about how each electron departs from its corresponding hole during excitations, resulting in charge transfer (CT). To obtain more insight into the characteristics of complexes, the Mulliken population approach, density of states (TDOS), natural population analysis (NPA), molecular electrostatic potential (MEP), condensed Fukui function, and relative nucleophilicity indices derived from orbital charge calculation results (NPA) were used. In addition, the photovoltaic properties of these compounds were studied comparatively. DFT band gap for 3 was 2.493, 5EE was 2.050, and 5ZZ was 2.071 eV. Furthermore, the power conversion efficiency (PCE) values for compound 3 and the isomeric mixture of compound 5 are calculated as 2.31%, and 2.82%, respectively. The results obtained can provide a useful reference for the development of organic compounds containing pyrene units in more efficient organic-based compounds for photovoltaic applications.

Synthesis, structural and spectral investigations of an optically active E-N′-(3,4-dimethoxybenzylidene)− 4-fluorobenzohydrazide crystal

Hydrazines represent a group of compounds with pronounced pharmacological activities, along with their possible use of optically active materials. In this contribution, E-N′-(3,4-dimethoxybenzylidene)− 4-fluorobenzohydrazide (DBF) was synthesized and chemically characterized by X-ray crystallography, IR, Raman, UV–VIS, and NMR spectroscopies. The intermolecular interactions governing the stability of the crystal were investigated by the Hirshfeld surface analysis. The structure optimization was performed starting from a crystallographic one. The highest resemblance between experimental and theoretical bond lengths and angles was obtained for the structure at M06–2X/6–311 + +G(d,p) level of theory. The Natural Bond Orbital (NBO) and Quantum Theory of Atoms in Molecules (QTAIM) analyses outlined the most important intramolecular interactions. The IR and Raman spectra vibrational peaks were assigned based on the Potential Energy Distribution (PED) analysis. Theoretical methods with high correlation factors and low mean absolute error reproduced the NMR chemical shifts. The excited state optimization of DBF with a difference of several nm modelled the peak at 330 nm in the experimental UV–VIS spectrum. The Condensed Fukui functions outlined the most active positions for electrophilic, neutrophilic, and radical attacks. The non-linear optical (NLO) Z-scan experiment determined the absorption coefficient and nonlinear refractive index, concluding that DBF can be used as NLO material. The ECOSAR prediction of toxicity showed that the material could be potentially dangerous for aquatic organisms.

Electrophilic substitution reactivity prediction of crown ether derivatives

AbstractLithium is important for the world's economic development because it is the primary component of batteries. Crown ether derivatives are widely used for the separation and enrichment of lithium. The conformations of the designed crown ether were studied using molecular dynamics simulation. The electrophilic substitution reactivities of different conformations were analyzed by the conceptual density functional theory (CDFT) and the frontier molecular orbital theory (FMO). The analysis results show that the reactivity of the phenyl group can be increased by the π–π conjugation effect and bonded oxygen atoms. According to the reduced density gradient (RDG), the van der Waals interactions between the phenyl functional groups and methyl groups also benefit the reactivity. According to the global softness and nucleophilicity index, the reactivity of is the highest. The condensed Fukui function, condensed local nucleophilicity index, and condensed local softness show that the electrophilic substitution reactivity of is the highest. also has the largest HOMO orbital composition. The analysis results of CDFT and FMO are consistent with each other, which suggests that the Koopmans approximation is suitable for the reactivity analysis of crown ether derivatives.

Isolation, Reactivity, and Tunable Properties of a Strained Antiaromatic Osmacycle.

Strain and antiaromaticity in compounds are recognized as two substantial destabilizing features, and consequently, realization of dual destabilizing features in a single molecule is challenging and far more difficult in a single ring. Moreover, transformation of an antiaromatic framework to different antiaromatic or aromatic species is a significant subject in antiaromatic chemistry and has attracted increasing interest. In this work, we isolated a highly strained antiaromatic metallacycle in which a cyclic metal vinylidene unit is embedded. Computational studies revealed its ring strain energies and antiaromatic character and showed that the metal incorporation and the phosphonium substituents play a crucial role in its stabilization. The mechanism of its formation has been illustrated by density functional theory (DFT) calculations and the isolation of a key intermediate. We further discovered diverse reactivities and structural reshuffling of this unusual strained antiaromatic complex according to its two destabilizing characters. We obtained two isomers of metallaindenes fused with oxiranes from the direct oxidation of the metal vinylidene or by nucleophilic addition to an isolated metallacyclocumulene formed by the reaction of metal vinylidene with hydroxide ion, achieving a reconfiguration of the antiaromatic framework. Transformations of the antiaromatic metallacycle by electrophiles to various aromatic metallaindynes have been achieved, and that a condensed Fukui function was employed to confirm the regioselectivity of the electrophilic additions, and the acid/base-induced aromaticity switch along with tunable photophysical properties were investigated. These interesting transformations not only enrich the chemistry of metal vinylidenes and antiaromatics and could also perform potentially as switchable optical materials.

Sulphur vs NH Group: Effects on the CO2 Electroreduction Capability of Phenylenediamine-Cp Cobalt Complexes.

The cobalt complex (I) with cyclopentadienyl and 2-aminothiophenolate ligands was investigated as a homogeneous catalyst for electrochemical CO2 reduction. By comparing its behavior with an analogous complex with the phenylenediamine (II), the effect of sulfur atom as a substituent has been evaluated. As a result, a positive shift of the reduction potential and the reversibility of the corresponding redox process have been observed, also suggesting a higher stability of the compound with sulfur. Under anhydrous conditions, complex I showed a higher current enhancement in the presence of CO2 (9.41) in comparison with II (4.12). Moreover, the presence of only one -NH group in I explained the difference in the observed increases on the catalytic activity toward CO2 due to the presence of water, with current enhancements of 22.73 and 24.40 for I and II, respectively. DFT calculations confirmed the effect of sulfur on the lowering of the energy of the frontier orbitals of I, highlighted by electrochemical measurements. Furthermore, the condensed Fukui function f - values agreed very well with the current enhancement observed in the absence of water.

Construction of a 0D/3D AgI/MOF-808 photocatalyst with a one-photon excitation pathway for enhancing the degradation of tetracycline hydrochloride: Mechanism, degradation pathway and DFT calculations

One-photon excitation has been demonstrated to be ideal for improving photon utilization effectiveness. We synthesized a unique 0D/3D AgI/MOF-808 composite using a hydrothermal method combined with in situ precipitation. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations indicated the electron migration direction, confirming the presence of a one-photon excitation pathway. The 0D/3D AgI/MOF-808 exhibited both excellent adsorption (189.01 mg/g) and photocatalytic properties for tetracycline hydrochloride (TCH). Electrochemical and photoluminescence (PL) tests showed that 0D/3D AgI (40 wt%)/MOF-808 had the highest photogenerated carrier transport and separation efficiency, with a TCH degradation efficiency of 83.02 % and a degradation rate 14.32 times higher than that of bare AgI. Photon utilization efficiency, carrier separation, and adsorption capacity expansion all contributed to the photocatalytic performance. The effects of pH and inorganic anions on the composite photocatalyst during the photocatalytic reaction were also investigated. The capture experiment demonstrated that ·OH and ·O2– were the primary active groups. Additionally, the stability was enhanced because the migration of electrons in AgI effectively limited the reduction of Ag+ to Ag0. Possible attack sites during TCH degradation were predicted using the condensed FuKui function (CFF), and potential degradation pathways were determined using ultrahigh-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS). The examination of the biotoxicity of TCH degradation intermediates demonstrated a reduction in their environmental risks.

Degradation of bisphenol A in an oxidation system constructed from Mo2C MXene and peroxymonosulfate

The etched Mo2C MXene with a layered structure was characterized as an environmentally friendly catalyst in the bisphenol A (BPA) removal by advanced oxidation. 99.75% of BPA was degraded in the oxidation system constructed using Mo2C MXene and peroxymonosulfate (PMS). The Mo2C MXene was recyclable, with a high removal percentage (89.29%) of BPA after even four cycles. The catalysis of Mo2C MXene on PMS was due to the Mo-deficit vacancy defects. The electron paramagnetic resonance technique and density functional theory (DFT)-based density of states calculations verified defect signals. In addition, the defective Mo2C MXene and PMS have strong binding and electron transfer capabilities. The reactive oxygen species (ROS, including O2•−, 1O2, SO4•−, and •OH) produced by Mo2C MXene activates PMS, leading to BPA degradation. The condensed Fukui function predicted the active sites of the BPA molecule and found that the O1, O2, C3, C4, C6, C12, C15, and C16 sites have higher electrophilic reactivity. The C, C–C bonds, or C4/C16 sites in the isopropyl group connecting the two phenolic rings were attacked first, then further transformed BPA into non-toxic or low toxic small molecule degradation products through a series of reactions such as bond-breaking, addition, hydroxylation, and ring-opening. Moreover, the Mo2C MXene/PMS system has strong applicability in actual water bodies. The study provides valuable insights into PMS activation by two-dimensional MXenes to remove toxic organic pollutants in an aqueous matrix.

Computational Studies on the Reactivity of Polycyclic Aromatic Hydrocarbons.

Polycyclic aromatic hydrocarbons (PAHs) are widely present in the environment as toxic pollutants. In this study, quantum chemistry methods are used to study reactions of PAHs in both particle and gas phases. Seven theoretical methods are exploited to predict the reactive sites of 15 PAHs in the particle phase. Among these methods, the performance of the condensed Fukui function (CFF) is optimum. The gas-phase reactions of eight PAHs are also investigated. Except for fluorene, CFF predicts correctly the gas-phase mono-nitro products for seven systems. The products of fluorene predicted by CFF are 1-nitrofluorene and 3-nitrofluorene, which is however inconsistent with the experimental results. Transition state theory is then used to investigate the reaction mechanism of fluorene. Calculated rate constants for 3-nitrofluorene and 2-nitrofluorene formation are much bigger than that for 1-nitrofluorene formation, which is in agreement with the experimental results.

Synthesis, spectral characterization, DFT and in silico ADME studies of the novel pyrido[1,2-a]benzimidazoles and pyrazolo[3,4-b]pyridines

The chemical behavior of 3-substituted-6,8-dimethylchromones 1-3 was studied towards two selected nucleophiles namely 1H-benzimidazol-2-ylacetonitrile (R1) and 5-amino-2,4-dihydro-3H-pyrazol-3-one (R2). A diversity of pyrido[1,2-a] benzimidazoles and pyrazolo[3,4-b]pyridines was efficiently synthesized through different transformation reactions; depending on the functional group present at C-3 position of the chromone moiety. The two nucleophiles reacted with acrylonitrile 1 through γ-pyrone ring opening at C-2 position followed by recyclization, while compounds 2 and 3 reacted with the two nucleophiles through addition onto the exocyclic double bonds followed by cycloaddition onto the nitrile functions. All theoretical computations were calculated by using Density Functional Theory (DFT) B3LYP method with the help of 6-311G(d,p) basis set. In theoretical studies, the global chemical activity descriptors (FMOs, electron affinity, ionization potential, hardness, softness, etc.) and MEP were calculated to predict the important information related with the stability and reactivity of the prepared molecules. Compound 7 which obtained through ring opening and recyclization of compound 1 by reagent R2 is the more stable product. Fukui functions (FFs) for the starting substrates 1-3 were determined by using the same level of theory. With the aid of local based descriptors in the form of condensed Fukui functions, the sites available for nucleophilic attack for compound 1 were C10 then at C8, and for compounds 2 and 3 were C14 then at C26. The electrons transfer occurs from the nucleophilic reagents (R1 and R2) to the starting substrates 1-3 as deduced from electrophilicity-based charge transfer study (ECT > 0). To explain the nonlinear optical (NLO) properties of the synthesized compounds, the dipole moment, polarizability, and first hyperpolarizability values (in the range 0.84 × 10−30 - 3.85 × 10−30 esu) have been calculated and compared with urea as a reference material. In addition, the 1H NMR chemical shifts of prepared compounds were simulated by GIAO manner and compared with experimental chemical shifts results. The “drug-likeness” and ADME appeared in good agreement with the Lipinski, Ghose and Veber rules, indicating the ability of the prepared compounds to be predictively orally active and bioavailable.

A Sensitive Co-MOF/CNTs/SiO2 Composite Based Electrode for Determination of Gallic Acid

A novel Co-based organic frameworks/carbon nanotubes/silicon dioxide (Co-MOF/CNTs/SiO2)-modified Au electrode was fabricated and taken as a platform for gallic acid (GA) detection. The composite combined the advantages of Co-MOF, CNTs and SiO2, and higher electrochemical response of Co-MOF/CNTs/SiO2-modified electrode indicated that the composite material exhibited satisfied the catalytic activity towards GA. Moreover, the electrochemical oxidation process of GA was deeply investigated on the surface of electrode based on computational investigations. Hirshfeld charges and condensed Fukui functions of each atom in GA were calculated. Besides, the catalysis of Co-MOF to GA was further investigated based on density functional theory. The quantitative determination of GA was carried out and showed a linear range between 0.05–200 μM, with low limit of detection. The sensitivity value of the self-assembled electrochemical sensor was calculated to be 593.33 μA cm−2 mM−1, and the selectivity, reproducibility and stability of the gallic acid sensor were also confirmed in the study.

Redox induced electron transfer in lithium polysulfide – A DFT study

This study reports the existence of redox-induced electron transfer in lithium polysulfides (RIET). The presence of redox-induced electron transfer in lithium polysulfides is confirmed using a DFT study. The sulfur gets oxidized, and lithium gets reduced during the removal of an electron from lithium polysulfides. The condensed Fukui function from Natural Population Analysis (NPA) charge and electron density augment RIET. The higher number of sulfur contributes to the total nucleophilic character of lithium polysulfide and holds lithium tightly. The presence of an electric field enhances the nucleophilicity of sulfur atoms and, hence, the reactivity of lithium polysulfides.

Novel solar/sulfite advanced oxidation process for carbamazepine degradation: Radical chemistry, transformation pathways, influence on disinfection byproducts and toxic changes

Advanced oxidation processes (AOPs) play a significant role in the elimination of micro-contaminants persistent in water, but challenges remain due to the high input of energy to initiate the AOPs. Herein, an AOP of integrating solar and sulfite autoxidation (solar/sulfite process) was developed to degrade carbamazepine (CBZ). Results revealed that solar/sulfite process was effective in eliminating CBZ. Sulfate and hydroxyl radicals (SO4•− and •OH) generated through radical chain reactions of sulfite autoxidation under solar irradiation contributed to 74.4% and 25.6% of CBZ degradation, respectively, based on the radical quenching tests, electron spin resonance (ESR) detection, and competition kinetics. Reaction pH exhibited significant effect on the CBZ degradation in solar/sulfite process, and the CBZ degradation was favored in neutral and alkaline conditions. The presence of bicarbonate (HCO3–) and humic acid (HA) retarded the CBZ degradation in solar/sulfite process, while chloride (Cl−) had negligible effect on the CBZ degradation. Integrating the UPLC-MS/MS analysis and the condensed Fukui function (CFF) calculation, five major degradation intermediates of CBZ were identified and the transformation pathway was proposed. Applying solar/sulfite as a pretreatment, the formation of disinfection byproducts (DBPs) during subsequent chlorination was significantly reduced, demonstrating its tremendous potential in eliminating micro-contaminants and controlling DBPs formation. The variation of acute toxicity throughout the solar/sulfite pretreatment and post-chlorination was recorded by the behavior of zebrafish larvae. It was found that CBZ degradation in solar/sulfite process led to its detoxification, while the increased acute toxicity during post-chlorination was a remind for the necessity of optimizing the disinfection steps to further reduce the formation of DBPs when solar/sulfite process was in practical applications.

Vibrational Spectral Investigations, Hybrid Computational Analysis, Hirshfeld Surface and Molecular Docking Studies of 3-Hydroxy-4-Nitrobenzaldehyde

As part of this study, the vibrational properties of 3H4NB were examined. Comparing observed and simulated vibrational spectra allowed for the identification of characteristic frequencies and the attribution of band names. For the density functional theory (DFT) calculations, the LSDA functional with 6-311++G(d,p) degree of approximation was used. Furthermore, the same level of theory was used to calculate molecular orbitals such as natural bond orbitals (NBOs) and the HOMO-LUMO energy gap. The condensed Fukui function and the molecular electrostatic potential (MEP) surface were used to determine the relative electrophilicity and nucleophilicity of the current molecule. Intermolecular hydrogen bonding interactions are studied using Hirshfeld surface analysis and fingerprint plots. Molecular docking analysis was used to investigate the compound's biological activities. The hydrogen bond active binding residues and binding energy of a chosen chemical with carcinogenic activity targets were examined.

Ce(Ⅲ) activates peroxymonosulfate for the degradation of substituted PAHs

Substituted polycyclic aromatic hydrocarbons (SPAHs) are being intensively investigated, considering their high toxicity. Additionally, the mechanism of the effect of substituents on the removal of SPAHs and the activation of Ce(III) ions on peroxymonosulfate (PMS) have not been explored. Here we evaluated the removal efficiency of SPAHs in the oxidation system constructed by Ce(Ⅲ) ions and PMS, with emphasized the effect of substituents on SPAHs degradation. Ce(Ⅲ) has high catalytic performance for PMS, and the degradation percentage of all pollutants was higher than 92%. The significantly negative correlation between the reaction rate constants of SPAHs and the highest occupied molecular orbital-the lowest unoccupied molecular orbital gap, confirms that substituents lead to the differences in the degradation of SPAHs. The generation of reactive oxygen species (SO4•−, •OH, and 1O2) is based on the electron transfer between Ce(Ⅲ) and PMS, and the contribution of ROS to substituted naphthalene varies due to the role of substituents. The Ce(Ⅳ)/Ce(Ⅲ) cycle accelerates the activation of PMS. Based on the transformation products and condensed Fukui function, the possible degradation pathways are inferred. In addition, inorganic anions and organic matter have little effect on the Ce(Ⅲ)/PMS system, which is a prerequisite for applying this system to real-world waste-water for SPAHs removal. This work demonstrates a new model of the degradation mechanism of SPAHs in the Ce(Ⅲ)/PMS system.

Theoretical study on the formation of Criegee intermediates from ozonolysis of pentenal: An example of trans-2-pentenal

In this study, we investigated the reaction mechanism and kinetics of ozone with trans-2-pentenal using density functional theory (DFT) and conventional transition state theory (CTST). At 298 K and 1 atm, the gas-phase reaction mechanisms and kinetic parameters were calculated at the level of CCSD(T)/6-311+G(d,p)//M06-2X/6-311+G(d,p). Both CC and CO bond cycloaddition as well as hydrogen abstraction were found. The calculations indicated that the main reaction path is 1,3-dipole cycloaddition reactions of ozone with CC bond with the relatively lower syn-energy-barrier of 3.35 kcal mol−1 to form primary ozonide which decomposed to produce a carbonyl oxide called a Criegee intermediate (CI) and an aldehyde. The subsequent reactions of CIs were analysed in detail. It is found that the reaction pathways of the novelty CIs containing an aldehyde group are extremely similar with general CIs when they react with NO, NO2, SO2, H2O, CH2O and O2. The condensed Fukui function were calculated to identify the active site of the chosen molecules. At 298 K and 1 atm, the reaction rate coefficient was 9.13 × 10−18 cm3 molecule−1 s−1 with atmospheric lifetime of 1.3 days. The calculated rate constant is in general agreement with the available experimental data. The branching ratios indicated that syn-addition pathways are prior to anti-addition. The atmospheric ratios for CIs formation and the bimolecular reaction rate constants for the Criegee intermediates with the variety of partners were calculated. Our theoretical results are of importance in atmospheric chemistry of unsaturated aldehyde oxidation by ozone.

Synthesis, characterization, DFT studies, and molecular modeling of azo dye derivatives as potential candidate for trypanosomiasis treatment

This research aims to synthesize four compounds (CMP1, CMP2, CMP3 and CMP4) and determine their suitability for the formulation of the drugs for the treatment of sleeping sickness caused by Trypanosoma cruzi, a vector-borne parasitic disease, commonly referred to as sleeping sickness. The synthesized azo dyes have been spectroscopically analyzed using UV–vis and FT-IR techniques along with detailed functional groups comparison through vibrational assignment. All theoretical computation was carried out within the framework of density functional theory (DFT) at the B3LYP/ 6–311++G(d) method and molecular properties such as frontier molecular orbital (FMO), natural bond orbital (NBO), nonlinear optics (NLO), condensed fukui function, and Total density of state (TDOS) have been evaluated. The results of the HOMO-LUMO energy analysis indicate that CMP4 possesses the largest energy gap of 3.327 eV compared to the rest of the compounds and has the highest stability. For the NBO analysis, CMP1 showed its highest stabilization energy with of 1243.14 kcal/mol, CMP2 at 47,120.45 kcal/mol, CMP3 at 694.91 kcal/mol, and CMP4 at 9471.63 kcal/mol. NLO shows CMP2 with the highest dipole moment of 10.59D and CMP1 with the lowest dipole moment of 2.5435D. All ligands exhibited higher binding affinities with 3ick and 5qq5 which suggest formation of stable complex with this protein compared to the standard drug. Therefore, molecular electronic structure and molecular docking investigation indicates that the azo compounds have unique reactivity and bioactivity towards vector-borne parasitic disease caused by Trypanosoma cruzi.