Fukui Indices Research Articles

Theoretical insights into phosphate chains: Density functional theory study and Zinc ion insertion reaction

The present research delves into a theoretical examination of phosphate chains using the density functional theory method with the RB3LYP/6-311G model. The geometry of the studied chains was optimized and their atomic charge densities were evaluated. Various parameters, such as HOMO and LUMO energies, energy difference (ΔE), chemical hardness, chemical potential, softness, and global electrophilicity index were thoroughly investigated. Moreover, vibrational frequencies were explored, highlighting both symmetric and asymmetric vibrations in the chains based on the computed IR and Raman spectra. Subsequently, an investigation into the Zinc ion insertion reaction in the studied phosphate chains was carried out. Several parameters were calculated to determine the electrophilic/nucleophilic character of these two constituents. The outcomes revealed that the phosphate chains display nucleophilic behavior and tend to release electrons, while the Zinc ion exhibits electrophilic tendencies and retains electrons. Notably, electron transfer occurs from the chains to the Zinc ion, with the chains acting as electron donors and the Zinc ion as an electron acceptor. The smaller overall electrophilicity gap between chain III and Zn2+ indicates the weak polar character of this reaction. Furthermore, favorable nucleophilic sites for the attack of the Zinc ion (Zn2+) on chain III were identified using the FUKUI indexes.

Dipeptidyl Peptidase 4 Inhibitors in Type 2 Diabetes Mellitus Management: Pharmacophore Virtual Screening, Molecular Docking, Pharmacokinetic Evaluations, and Conceptual DFT Analysis

Dipeptidyl Peptidase 4 (DPP-4) expressed on the surface of many different cells is a promising target to develop new candidates for Type 2 diabetes mellitus (T2DM) management. In this light, we performed a computer-aided simulation involving 3-D pharmacophore screening, molecular docking, and drug-likeness assessment to identify novel potential DPP-4 inhibitors with an improved physicochemical profile to treat T2DM. In addition, global reactivity descriptors, including HOMO and LUMO energies, HOMO-LUMO gaps, and Fukui indices, were computed to confirm the essential structural features to achieve DPP-4 activity. The gathered outcomes recommend that eight out of 240 million compounds collected from eight pre-built databases (Molport, Chembl30, ChemDiv, ChemSpace, Mcule, Mcule-ultimate, LabNetwork, and ZINC) are drug-like and nontoxic, and may serve as starting points for designing novel, selective, and potent DPP-4 inhibitors. Furthermore, the success of the current workflow to identify DPP-4-potential inhibitors strengthens its potential efficiency to also predict natural compounds as novel adjutants or main therapy for T2DM or discover hit compounds of other targets.

DFT, Fukui indices, and molecular dynamic simulation studies on corrosion inhibition characteristics: a review

DFT, Fukui indices, and molecular dynamic simulation studies on corrosion inhibition characteristics: a review

Sulfite activation by Jahn-Teller-driven oxygen vacancies Cu-Mn composite oxide for chlortetracycline degradation

Copper-manganese composite metal oxides (CuMnOy) were prepared by hydrolysis-driven oxidation-reduction method and used to activate sulfite to degrade chlortetracycline hydrochloride (CTC) for the first time. The Jahn-Teller ions Mn3+ and Cu2+ exist in CuMnOy, which form a solid electric charge transport redox system and ensure the continuous generation of reactive oxygen species (ROS). Through the systematic study of the experimental parameters such as sulfite concentration, catalyst metal molar ratio, catalyst amounts and initial pH, the optimal degradation rate of CTC could reach 91.74% within 10 min and 94.46% after 30 min. The major reactive radicals were determined by radical quenching experiments and electron paramagnetic resonance (EPR) trapping techniques, and it was confirmed that SO4•- and •O2- played a nonnegligible role in the process of degrading CTC. Density functional theory (DFT) calculations show that higher Fukui indices (f- and f0) of CTC sites are more vulnerable to free radical attack. CuMnOy has low CTC degradation intermediate toxicity, high catalytic performance, good anti-interference ability, reusability and stability, and possesses decent application potential in the actual water treatment field.

Molecular insights into the corrosion inhibition mechanism of omeprazole and tinidazole: a theoretical investigation

ABSTRACT In many studies published in recent years, corrosion scientists proved that various drug molecules can exhibit high inhibition performance against the corrosion of metal surfaces and alloys. This study presents the adsorption behaviour and inhibition mechanism of Omeprazole and Tinidazole on steel surface in gas phase and aqueous acidic conditions using quantum chemical calculations and molecular dynamics simulations. Well-known quantum chemical parameters such as EHOMO, ELUMO, energy gaps, dipole moment, global hardness, softness, electrophilicity, electrodonating power, electroaccepting power and the fraction of electron transfer, were calculated to understand the corrosion inhibition properties and interactions with the steel surface of the studied molecules. Fukui indices analysis was performed to identify the local reactivities of the molecules. Additionally, Monte Carlo simulations were used to determine the optimal adsorption configuration of the inhibitors onto a Fe (1 1 0) surface. The study's findings provide valuable insights into preventing corrosion of steel surfaces in aqueous acidic environments. The theoretical data obtained was evaluated in terms of Maximum Hardness, Minimum Polarizability and Minimum Electrophilicity Principles.

Interaction between components of polymeric light emitting electrochemical cells: A DFT case study for MDMO-PPV/KCF3SO3/PEO system

Polymer light emitting electrochemical cells (PLECs) are organic electronic devices that define interesting alternatives to organic light-emitting devices. However, despite their potential application, some of the basic operational mechanisms involved in their operation are still not completely understood. In this context, here we report a theoretical attempt to unravel some basic aspects on this subject considering a model system based on poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4- phenylene vinylene] (MDMO-PPV), potassium(I) trifluoromethanesulfonate (KCF3SO3) and polyethylene oxide (PEO). Structural and reactivity properties of the constituents were evaluated via DFT-based electronic structure calculations. Condensed-to-atoms Fukui indexes were estimated via Hirshfeld partition charge to identify preferred sites for PLEC component’s interactions. The results suggest that the presence of ionic salt induces significant changes on the semiconducting polymer’s electronic properties, which are dependent on the number of salt molecules and their oxidation state, influencing the devices’ charge dynamics (injection and transport), reinforcing previous results obtained for other similar systems.

Enhanced denitrification of aniline and its derivatives by catalysts, anions, and co-fuels during supercritical water oxidation process

We investigated the denitrification performance of aniline and its derivatives (N-methylaniline and N, N-dimethylaniline) in supercritical water oxidation (SCWO) under varying conditions (temperature: 643–743 K, reaction time: 0.5–4 min, pressure: 24.0 MPa, oxidation coefficient: 300%). Cu2 + proved to be an efficient homogeneous catalyst, generating radicals via a Fenton-like reaction. Isopropyl alcohol (IPA) outperformed methanol and ethanol as a co-fuel, enhancing TN removal due to its higher heating value. Nitrogen-containing product distribution revealed that N2 generation correlated with org-N depletion, especially with Cu2 + and IPA. A denitrification mechanism was elucidated using DFT, with Fukui indices, EHOMO, and ELUMO highlighting aniline's greater susceptibility compared to MA and DMA. Our findings provide insights into optimizing SCWO denitrification using aniline derivatives, shedding light on sustainable nitrogen removal processes.

Computational and theoretical chemistry of newly synthesized and characterized 2,2’-(5,5’-(1,4-phenylene)bis(1H-tetrazole-5,1-diyl))bis-N-acetamides

Energetic heterocycles, including pyridines, triazoles, and tetrazoles, exhibit greater density, heats of formation, and oxygen balance compared to their carbocyclic counterparts, making them a promising approach for synthesizing novel bis-tetrazole acetamides. Synthesized compounds A-F, some of which feature a chlorine atom attached to the phenyl ring, serve as valuable synthons for aryl coupling reactions. Analysis via 1H-NMR and 13C-NMR spectroscopy, as well as density functional considerations through B3LYP functional correlation with 6-311 + + G(d) and 6-31G(d) basis set, revealed the observed LUMO/HOMO energies and charge transfer within the molecule. Additionally, the dipole moment, chemical hardness, softness, ionization potential, local reactivity potential via Fukui indices and thermodynamic properties (entropy, enthalpy, and Gibbs free energy) of the molecule were calculated through density functional theory studies. In addition, Molecular Docking studies were conducted to investigate the anti-cancer potential of synthesized heterocyclic compounds against caspase 3, NF-KAPPA-B and P53 protein. Molecular docking analysis demonstrated a potent interaction between 2,2’-(5,5’-(1,4-phenylene)bis(1H-tetrazole-5,1-diyl))bis-N-(2,4-dinitrophenyl) acetamides (6d) and TP53 and NF-KAPPA-B with binding energies of − 11.8 kJ/mol and − 10.9 kJ/mol for TP53 and NF-KAPPA-B, respectively. Similarly, 2,2’-(5,5’–(1,4-phenylene)bis(1H-tetrazole-5,1-diyl))bis-N-(2-chlorophenyl) acetamides (6f) exhibited a strong interaction with caspase-3 with binding energy of -10.0 kJ/mol, indicating their potential as therapeutic agents against these proteins. Furthermore, the findings of current study was further strengthen by 100 ns molecular dynamics (MD) simulations. Finally, theoretical studies of oxygen balance and nitrogen percentage suggest that these molecules can be utilized as energetic materials.Graphical

Effect of ionic liquid as corrosion inhibitor for 6061 aluminium alloy-(electrochemical and quantum chemical approaches)

ABSTRACT Ionic liquid 1,3-dimethylimidazolium dimethyl phosphate (DIDP) is used as a possible green inhibitor for the corrosion control of 6061 aluminium alloy in 0.25 mol/L HCl is described in the study. Study involved electrochemical methods carried out at various temperatures by changing the concentrations of DIDP. Kinetic and thermodynamic parameters were determined using the Arrhenius rate law and transition state equations, respectively. Physisorption of the inhibitor takes place and the adsorption follows Freundlich isotherm. Surface morphology was studied by scanning electron microscopy (SEM), atomic force microscopy (AFM), and energy-dispersive X-ray analysis (EDAX) techniques. Quantum chemical studies were done by the density functional theory (DFT). The maximum inhibition efficiency of DIDP on 6061 aluminium alloy was about 78% for the concentration of 1000 ppm at 303 K. The mechanistic aspects of DIDP adsorption onto the metal surface were supported by quantum chemical studies. HOMO and LUMO of the optimized structure and quantum chemical descriptors confirmed the adsorption of the inhibitor on the metal surface. Mulliken charge population was used to identify the DIDP molecule’s high electron density region, and Fukui indices confirmed the interaction between metal and inhibitor.

Tunable Anticorrosive Effects of Newly Synthesized Benzothiazole Azo Dyes by Potassium Iodide Synergism for Carbon Steel in 1 M HCl: Combined Experimental and Theoretical Studies.

Herein, we synthesized three novel benzothiazole azo dyes, including 4-chloro-2-(4-methyl-benzothiazol-2-ylazo)-phenol (CMBTAP), 1-(6-chloro-benzothiazol-2-ylazo)-naphthalen-2-ol (CBAN), and 2-(6-chloro-benzothiazol-2-ylazo)-4-methyl-phenol (CBAMP), and investigated their corrosion inhibition effect on carbon steel. The dyes were characterized by Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance (NMR), 13C NMR, and mass spectroscopy. Weight loss, electrochemical impedance spectroscopy, and potentiodynamic polarization measurements were performed to investigate the corrosion inhibition effect of the dyes on carbon steel in a 1.0 M HCl solution. The synergistic effects of the dyes with potassium iodide (KI) were also investigated. The inhibition efficiency (IE%) was enhanced by increasing the dose of the dyes (1 × 10-5 to 2 × 10-4 M) and decreased as the temperature increased from 25 to 45 °C. The addition of KI to a 1.0 M HCl solution containing the dyes improved the performance and efficiency as iodide ions promoted the formation of inhibition films on the surface of carbon steel. The dyes are mixed-type inhibitors, according to Tafel polarization. Scanning electron microscopy and energy dispersive X-ray analysis were used to evaluate the surface morphology of carbon steel sheets. Quantum theory calculations were utilized to evaluate the relationship between the dyes' chemical structures and their inhibitory efficiency, which confirmed the experimental results. The calculations revealed that the dyes have low energy gap and Milliken and Fukui indices. Among all of the dyes, CMBTAP showed the highest adsorption energy. The corrosion IE was in the order CMBTAP > CBAMP > CBAN.

Atmospheric oxidation of furanones by •OH and •Cl radicals: In situ FTIR rate coefficient determinations, SAR and theoretical studies

Gas-phase kinetics of the overall reactions of •OH and •Cl radicals with dihydrofuran-3(2H)-one (oxolan-3-one) and dihydro-2-methyl-3(2H)-furanone (2MTHF-3-one) were studied at 298 K and atmospheric pressure. The rate coefficients were determined using the relative method in a 480 L multipass glass reactor coupled to an FT-IR detection system. The rate coefficients found for oxolan 3-one and 2MTHF-one with •OH radicals (k1 and k2) and with •Cl atoms (k3 and k4) at 298 K and atmospheric pressure (in cm3 molecule−1 s−1) were: k1 = (1.86 ± 0.29) × 10−11, k2 = (2.64 ± 0.47) × 10−11, k3= (1.15 ± 0.28) × 10 −10, and k4 = (1.33 ± 0.32) × 10−10, respectively. Reactivity trends were developed by comparison with other similar structures and Fukui indices employed to determine the reactivity of different sites on the ring. The singularity of the reaction with •OH was assessed by computational studies which showed the formation of several stable hydrogen bonded complexes, explaining the difference with the reaction with the •Cl atom. SAR estimations of the rate coefficients were calculated and compared to the experimental values.

Synergy between UV light and trichloroisocyanuric acid on methylisothiazolinone degradation: Performance, kinetics and degradation pathway.

Methylisothiazolinone (MIT) is widely used in daily chemicals, fungicides, and other fields and its toxicity has posed a threat to water system and human health. In this study, ultraviolet (UV)/trichloroisocyanuric acid (TCCA), which belongs to advanced oxidation processes (AOP), was adopted to degrade MIT. Total chlorine attenuation detection proved that TCCA has medium UV absorption and a strong quantum yield (0.49 mol E−1). At a pH of 7.0, 93.5% of MIT had been decontaminated after 60 min in UV/TCCA system (kobs = 4.4 × 10−2 min−1, R2 = 0.978), which was much higher than that in the UV alone system and TCCA alone system, at 65% (1.7 × 10−2 min−1, R2 = 0.995) and 10% (1.8 × 10−3 s−1, R2 = 0.915), respectively. This system also behaved well in degrading other five kinds of contaminants. Tert-butanol (TBA) and carbonate (CO32−) were separately used in quenching experiments, and the degradation efficiency of MIT decreased by 39.5% and 46.5% respectively, which confirmed that HO• and reactive chlorine species (RCS) were dominant oxidants in UV/TCCA system. With TCCA dosage increasing in a relatively low concentration range (0.02–0.2 mM) and pH decreasing, the effectiveness of this AOP system would be strengthened. The influences of coexisting substances (Cl−, SO42−, CO32−, NO2− and NO3−) were explored. MIT degradation pathways were proposed and sulfur atom oxidation and carboxylation were considered as the dominant removal mechanisms of MIT. Frontier orbital theory and Fukui indexes of MIT were employed to further explore the degradation mechanism.

Electrochemical, surface analysis, computational and anticorrosive studies of novel di-imine Schiff base on X65 steel surface

The inhibitory effect of di-imine-SB namely ((N1Z, N4E)-N1, N4-bis (4 (dimethylamino) benzylidene) butane 1,4-diamine) on X65-steel in 1 M HCl has been investigated experimentally and theoretically. The electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and weight loss outcomes display the anticorrosion properties of “di-imine- SB”. The inhibitory efficiency exceeds 90% at the optimal concentration of 1 × 10–3 M “di-imine- SB”. The metal surface was examined further using scanning electron microscope (SEM) and energy dispersive X-ray (EDX). The effectiveness of the di-imine-SB is returned into its adsorption on X65-steel surface and found in agreement with Langmuir adsorption isotherm. According to the standard Gibbs free energy of adsorption ({Delta G}_{ads}^{^circ }), di-imine-SB adsorption tends to be chemical rather than physical, it increases the activation energy ({mathrm{E}}_{a}) of metal dissolution reaction and makes it hard to occur. The PDP data suggested anodic and cathodic type of the di-imine-SB inhibitor. Meanwhile, increasing the resistance of X65-steel to 301 Ω cm2 after adding 1 mM of di-imine-SB confirms its protective effect. Whereas, the positive value of the fraction of electron transference (ΔN, 0.746), confirms the affinity of di-imine-SB to share electrons to the partially filed 3d-orbital of Fe forming strong protective film over X65-steel surface. Aided by Monte Carlo (MC) simulation, the calculated adsorption energy (Eads) suggests excessive adsorption affinity of di-imine-SB on metal surface over the corrosive chlorides and hydronium ions. A good correlation between the theoretical hypothesis and the experimental inhibition efficiency has been achieved. The comparative study showed the superior of the di-imine-SB as potential corrosion inhibitor compared with those reported before. Finally, global reactivity descriptors; electron affinity (A), ionization potential (I), electronegativity (χ), dipole moment (µ), global hardness (eta), electrophilicity index and, Fukui indices were also calculated and found well correlated to the reactivity of di-imine-SB.

Mechanistic insight into adsorption and anti-corrosion capability of a novel surfactant-derived ionic liquid for mild steel in HCl medium

A novel cetylpyridinium picrate ionic liquid (CPP) was synthesized and investigated for its corrosion inhibition trait on mild steel (MS) substrate in 1 M HCl. The molecular structure of CPP was elucidated by FT-IR and NMR spectroscopy. Gravimetric experiment, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization technique (PP) were used to quantify the corrosion inhibition efficiency of CPP. Gravimetric results at 30 °C showed an appreciably high inhibition efficacy of 90.79% at an extremely low concentration of CPP (8 × 10−7 M) which is further raised with temperature attaining maximum protection of 99.04% at 70 °C at the same concentration. Adsorption of CPP at MS-electrolyte interface was ideally compatible with Langmuir adsorption isotherm. Surface analysis by X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), contact angle measurement, and FT-IR spectroscopy confirms that CPP forms an organic–inorganic hybrid protective layer to prevent the surface from corrosive ions. Scanning electron microscopy (SEM) micrographs accentuated reduced heterogeneity of metal surface in the presence of adsorbed CPP. The computational methods (DFT, fukui indices calculation, and MD simulation) were exploited to envisage the inhibition mechanism of CPP.

Adsorptive investigation of the anticorrosion properties of natural chrysin on carbon steel in acid–chloride system: combined theoretical and experimental approach

PurposeOwing to the toxicity, biodegradability, and cost of most corrosion inhibitors, research attention is now focused on the development of environmentally benign, biodegradable, cheap, and efficient options. In consideration of these facts, chrysin, a phytocompound of Populus tomentosa (Chinese white poplar) has been isolated and investigated for its anticorrosion abilities on carbon steel in a mixed acid and chloride system. This highlights the main purpose of the study.Design/methodology/approachChrysin was isolated from Populus tomentosa using column chromatography and characterized using Fourier Transform Infrared Spectroscopy and Nuclear Magnetic Resonance Spectroscopy. The investigations are outlined based on theory (Fukui indices, condensed density functional theory and molecular dynamic simulation) and experiments (electrochemical, gravimetry and surface morphology examinations).FindingsTheoretical evaluations permitted the description of the adsorption characteristics, and molecular interactions and orientations of chrysin on Fe substrate. The interaction energy for protonated and neutral chrysin on Fe (110) were −149.10 kcal/mol and −143.28 kcal/mol, respectively. Moreover, experimental investigations showed that chrysin is a potent mixed-type corrosion inhibitor for steel, whose effectiveness depends on its surrounding temperature and concentration. The optimum inhibition efficiency of 78.7% after 24 h for 1 g/L chrysin at 298 K indicates that the performance of chrysin, as a pure compound, compares favorably with other phytocompounds and plant extracts investigated under similar conditions. However, the inhibition efficiency decreased to 62.5% and 51.8% at 318 K after 48 h and 72 h, respectively.Originality/valueThe novelty of this study relies on the usage of a pure compound in corrosion suppression investigation, thus eliminating the unknown influences obtainable by the presence of multi-phytocompounds in plant extracts, thereby advancing the commercialization of bio-based corrosion inhibitors.

Monte Carlo and DFT calculations on the corrosion inhibition efficiency of some benzimide molecules

Calculations using density functional theory (DFT) and Monte Carlo methods were performed on 2-methylbenzimidazole, 2-mercaptobenzimidazole, 2-aminobenzimidazole, benzotriazole, and benzimidazole to determine their corrosion inhibition efficiency. The molecular structure was optimized geometrically using DFT calculations at the B3LYP/6– 311 G++(d,p) and b2plypd3/aug-cc-pvdz basis set level in protonated and non-protonated species in gas and water. In this study, HOMO, LUMO, bandgap, ionization energy, electronegativity, hardness, softness, electrophilicity and nucleophilicity, electron transfer, back donation energy and condensed Fukui indices are used to assess a molecule's local reactivity. Theoretical investigations can precisely establish the geometrical dimensions of a molecule and correctly explain the quantum properties of inhibitors. The mechanism of interaction between inhibitors and metal surfaces in a specified molecule is studied using molecular dynamics. The benzimidazole functional groups absorbed energy linearly on metal surfaces, with quantum characteristics determined using density functional theory and an ab initio technique. Importantly, the findings of this conceptual model are consistent with the corrosion inhibition efficiency of earlier experimental investigations.

DFT Studies and Acetylcholinesterase Inhibition Capacity Analysis of an Adamantane-Isothiourea Derivative via Docking and MD Calculations

In this work, 4-bromobenzyl(Z)-N'-(adamantan-1-yl)-4-phenylpiperazine-1-carbothioimidate (4BAPC), an adamantane-isothiourea derivative, was studied through density functional theory (DFT) at the M06-2X/6 − 311 + G(2df,2p) level of theory, where its structural, vibrational, and quantum-chemical properties were comprehensively described. The analysis of the IR and Raman frequencies, with the help of potential energy distribution (PED) calculation, allowed the assignment of several characteristic vibrations that may be used in the identification of other adamantane-isothiourea derivatives. Solvation-free energy (SFE) calculations in water, ethanol, acetone, and chloroform were carried out, where acetone and chloroform showed the most negative values, −23.34 and −23.33 kcal/mol, respectively, suggesting that these two solvents better solubilize 4BAPC. Also, the SFE value in water, −10.49 kcal/mol, indicates good solubility in an aqueous medium. FMOs, MEP, ALIE surfaces, and Fukui indices calculations allowed to identify that the most reactive sites of 4BAPC comprise the aromatic rings and piperazine moiety. Acetylcholinesterase (AChE) inhibition capacity presented by 4BAPC was evaluated through molecular docking and molecular dynamics (MD) calculations. Docking binding affinity and MMPBSA binding energy showed, respectively, values of −9.2 and −29.954 kcal/mol, which indicates strong evidence for the AChE inhibitory potential by 4BAPC.

Synthesis, Crystal structure, Hirshfeld surface interactions, anti-corrosion analysis, DFT calculations, Docking studies and evaluation of the antioxidant activity of a new zwitterion Schiff base

The title compound Schiff base (SB) named: (6E)-3-benzyloxy-6- [ [ [2‑hydroxy-1,1-bis(hydroxymethyl)ethyl]amino]methylene]cyclohexa-2,4‑dien-1-one(I) (C18 H21 N O5), was synthesized via the reaction of 4-benzyloxy-2‑hydroxy-benzaldehyde with 2-amino-2-(hydroxymethyl)propane-1,3-diol (Trizma)and characterized by single-crystal diffraction XRD, infrared spectra, 1H and 13C NMR spectroscopy. It crystallizes as a zwitterion, (E)-5-(benzyloxy)-2-(((1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl)iminio)methyl)phenolate (II), with the phenolic H atom having migrated to the imino group. Additionally,Hirshfeld surface analysis (HS), two-dimensional fingerprint plots and energy frameworks of II were calculated to quantify the interatomic interactions present in the crystal.The antioxidant activity of the synthesized compound was evaluated by five tests: ABTS, DPPH, O-pH, SNP and reducing power activity. Furthermore, molecular docking calculations were performed for SB compound at the active site of mushroom tyrosinase (PDB ID:2Y9X) to determine the binding affinity between the title compound and receptor protein. Results reveal a great affinity (-6.16 kcal/mol) of the SB to the protein that is mainly dominated by hydrogen bonds. In this work, experimentally, the assessment of the anti-corrosion ability of this compound by different methods showed excellent inhibition. On the other hand, anti-corrosion potentials of title compound have been investigated using density functional theory (DFT) in gas and solvent phases. Chemical reactivity descriptors like global hardness (η), chemical potential (u), electronegativity (χ), electrophilicity (ω) and number of transferred electrons (ΔN) were computed at ωB97XD with 6–311+g(d) basis set. The local reactive sites on this compound were studied using Fukui indices, local philicity index and dual descriptor. The quantum chemical calculation suggests a good charge transfer tendency from the title compound to the low-lying vacant d-orbitals of iron (The average value of charge transfer is ΔNIII/Fe.≈ 2.21 and ΔNIII/Cu.≈ 0.07). The C7 atom is the nucleophilic sites (Δf(r)C7 ≈ 0.25) on the inhibitor for effective interaction on the metal surface as shown by local reactive descriptor in gas and solvent. Furthermore, the results obtained from DFT and TD-DFT studies are in excellent agreement with experimental data (structure geometry (RMS Error ≈ 0.3 Å), optical properties (λexp-Cal ≈18 nm) and inhibition efficiencies).

Computational insights into the adsorption mechanisms of anionic dyes on the rutile TiO2 (1 1 0) surface: Combining SCC-DFT tight binding with quantum chemical and molecular dynamics simulations

Metal oxides are gaining momentum rapidly for application in water pollutant remediation. In this study, the adsorption proprieties of two anionic dyes, i.e., acid yellow 36 (AY36) and acid orange 6 (AO6) on the (110) surface of rutile titanium dioxide (TiO2) in an aqueous medium were investigated using computational methods. The density functional theory (DFT) was used to determine the reactivity of organic molecules by calculating the frontier molecular orbital energies, energy gap (ΔEgap), chemical hardness (η), chemical softness (σ), electronegativity (χ), chemical potential (μ), electrophilicity (ω), the fraction of electrons transferred (ΔN), back-donation energy (ΔEback-donation), Mulliken charge, and Fukui indices. The obtained results showed that the AY36 molecule is more reactive than the AO6 molecule and may have a good adsorption capability compared to the AO6 dye. The most favorable adsorption configurations of AY36 and AO6 molecules were investigated using molecular dynamics (MD) simulation. The calculated interaction energies by MD simulation showed that the TiO2 (110) surface has a high sensitivity to interact with the two anionic dyes, with more affinity toward the AY36 molecule. Furthermore, to get deep insights into the chemistry of interactions between the anionic dyes and the TiO2 (110) surface, the self-consistent charge density functional tight-binding (SCC-DFTB) method was carried out. Results showed that anionic dyes adsorbed on the TiO2 (110) surface by forming covalent bonds between oxygen atoms of the sulfonic group and Ti atoms. Theoretical insights from this work would serve as a guide for researchers to explore the application of oxides in water pollutant remediation.

Antioxidant activity of new synthesized imine and its corresponding α-aminophosphonic acid: Experimental and theoretical evaluation

A Schiff base (I1) and its corresponding α-aminophosphonic acid (P1) were synthesized using a simple and rapid preparation method and with a chemical yield of up to 75% and 68%, respectively. The structures of I1 and P1 were experimentally characterized by IR, 1H NMR, 13C NMR and 31P NMR spectroscopic methods. A test of their antioxidant activities was carried out and indicated that I1 and P1 were able to scavenge the DPPH radical. The main objective of this research was the theoretical study of the antioxidant power of I1 and P1. Density functional theory (DFT) calculations at the B3LYP/6-311+G(d, p) level were performed to determine BDE, PA, ETE, IP, PDE, spin density distribution parameters and HOMO-LUMO energies in order to study the antioxidant potential of the title products in the gas phase. According to the theoretical results, the abstraction of H atoms from the 2-OH and 1-OH groups of I1 and P1 compounds, respectively, is most preferable during the free radical scavenging process. In addition, it was shown that HAT is the thermodynamically dominant mechanism compared to SPLET and SET-PT. The calculated data of the antioxidant activity of I1 and P1 are consistent with the experimental results. A study of the chemical reactivity of these molecules was carried out. Calculations of the global parameters (chemical potential (μ), hardness (η), softness (S) and electrophilicity index (ω)) and Fukui indices of the studied compounds were done and discussed. These molecules have an electrophilic character. The Fukui functions were calculated to specify the interaction sites of these products.