Fukui Function Indices Research Articles

Investigation of Antiviral Activities of Nickel and Copper Complexes with Macrocyclic Ligands against Crimean-Congo Hemorrhagic Fever by In Silico Calculations

For the first time, electronic characteristics of potential drug candidates and their inhibitory activities have been linked thanks to this work. Synthesized copper and nickel complexes with trans-N1,N8-bis(2-cyanoethyl)-2,4,4,9,11,11-hexamethyl-1,5,8,12-tetraazacyclotetradecane (tet-bx) ligand, as well as the proposed hypothetical complexes, were properly examined by the appropriate calculation method in atomic and molecular dimensions. The appropriate calculation level was achieved by using the IR spectroscopic data of the tet-bx ligand. The experimental and calculated bond stretching frequencies were compared for synthesized complexes [Ni(tet-bx)](ClO4)2 (1), [Cu(tet-bx)](ClO4)2 (2), [Ni(tet-bx)(NCS)2] (3), and [Ni(tet-bx)(ClO4)Cl] (5). Some bond stretching frequencies of hypothetical complexes [Cu(tet-bx)(NCS)2] (4) and [Cu(tet-bx)(ClO4)Cl] (6) have also been proposed and their molecular structure were determined. To analyze the electronic behavior of the examined complexes at the atomic level, Fukui function indices (nucleophilic f+ and electrophilic f- populations) were determined. Furthermore, antibacterial and antiviral inhibition efficiency of the complexes against Crimean-Congo hemorrhagic fever has been investigated by docking studies

Substituent Effects on the Carboxylation Step of Allyllic Substrates: A Density Functional Theory Study

AbstractNi(0/I) catalysed direct carboxylation of allyl alcohols represents an effective way to create β, γ‐unsaturated carboxylic acids, with the carboxylation to be a crucial elementary step. Using density functional theory (DFT) calculations, we investigated how substituents affected the carboxylation process. The energy barrier of the carboxylation process is relatively low in the case of Ni(0), which can be efficiently lowered down by electron‐donating group (at allyl‐α‐C). Other distal sites have less of an impact. The steric effect on this reaction is insignificant, although there is a certain threshold. Multiple linear regression was taken to fit the energy barrier of the carboxylation step using the NPA, Fukui function, and Wiberg bond index of the pre‐intermediate The results showed that the energy barrier of the carboxylation step can be easily predicted by the property parameter of the pre‐intermediate, eliminating the complex transition state calculation.

On the efficiency of barbituric acid and its thio derivatives as aluminium corrosion inhibitors: A computational study

The corrosion inhibition efficiency of the barbituric acid and its thio derivatives were herein monitored by the execution of a variety of density functional theory (DFT) computations. The 1,3-diazinane-2,4,6-trione (BA); 6-sulfanylidene-1,3-diazinane-2,4-dione (1S); 2,6-bis(sulfanylidene)-1,3-diazinan-4-one (2S); and 1,3-diazinane-2,4,6-trithione (3S) compounds were devoted as aluminum corrosion inhibitors. Global and local quantum descriptors were determined for the neutral and protonated forms of the modelled inhibitors in gas and aqueous phases. As the global indices indicated, reverse and proportional correlations were noticed between the number of S atoms in the studied inhibitors and their ionization potential and electron affinity. Accordingly, the inhibition efficiency of the studied compounds generally increased in the order BA < 1S < 2S < 3S. In the same line, the obtained values of local nucleophilic and electrophilic Fukui function indices affirmed the further favorability of the 3S compound over other studied analogs. Utilizing molecular dynamics simulations, the most favorable configurations for inhibitor∙∙∙aluminium (Al)(111) complexes were characterized. Binding energy calculations revealed the efficiency of the corrosion inhibition increased in the order BA∙∙∙Al (−0.95 eV) < 1S∙∙∙Al (−1.71 eV) < 2S∙∙∙Al (−2.16 eV) < 3S∙∙∙Al (−2.49 eV). Upon the presented findings, the current work would be a sufficient linchpin for future research related to the aluminium corrosion inhibition process, particularly with the incorporation of acids and their thio derivatives.

Experimental and theoretical studies on corrosion inhibitory action of Peganum harmala (L.) seeds extract on carbon steel in 1M HCl

The objective of this study is to test the inhibitory efficiency of the methanol extract of P. harmala against the corrosion of carbon steel C38 in 1M hydrochloric acid by gravimetric method and electrochemical measurements. The results indicated that the methanol extract of P. harmala is a good inhibitor of carbon steel. The inhibition efficiency increases with the increase of the concentration of the inhibitor. The nature of adsorption of the extract on carbon steel surface was in conformity with Langmuir isotherm. Both kinetic and thermodynamic parameter of adsorption allows us to suggest chemical adsorption of this inhibitor on the metal. Potentiodynamic polarization measurements show that P. harmala acts as mixed type inhibitor. The result of EIS was correlating with the result of polarization measurement. A theoretical study was done in solution for major alkaloids isolated from P. harmala seeds, and was investigated using density functional theory (DFT) at the B3LYP/6-31G(d,p) basis set level through the relationship between their molecular and electronic structure. The quantum chemical parameters such as E HOMO (highest occupied molecular orbital energy), E LUMO (lowest unoccupied molecular orbital energy), energy gap (ΔE), dipole moment (μ), absolute hardness (η), absolute softness (S), the absolute electronegativity (χ), the fractions of electrons transferred from the inhibitor molecule to the metallic atom (ΔN) and the electrophilicity index (ω) were calculated. The local selectivity and reactivity has been analyzed through the Fukui function indices in order to compare the possible sites for nucleophilic and electrophilic attacks.

Gold nanoparticles green synthesis with clove oil: spectroscopic and theoretical study

Certain limitations of obtaining metal nanoparticles with the use of synthetic chemicals have sparked a great interest in scientists to develop green synthesis procedures which use non-toxic and eco-friendly reagents and wastes. Essential oils have the potential to simultaneously act as reducing agents and stabilizers for the synthesis of metal nanoparticles. In the present work, we have synthesized gold nanoparticles (AuNPs) using clove oil (Syzygium aromaticum L. essential oil) as the main reducing agent and stabilizer. The AuNPs solutions were characterized by UV–VIS spectroscopy, and the isolated solid AuNPs were analyzed by Fourier transformed infrared spectroscopy. Various reactivity descriptors determined in terms of Conceptual Density Functional Theory, for the 16 predominant components of clove oil, have been calculated by using the quantum chemical B3LYP/6-311G** level of theory. With the aim to validate the chosen theoretical method, the calculated infrared spectra have been compared with the available experimental spectra. Moreover, the active centers for nucleophilic and electrophilic attacks have been identified through the analysis of atomic partial charges and Fukui function indices. The obtained theoretical results should be considered as a starting point for the prediction of the appropriateness of essential oils for the direct green synthesis of metal nanostructures.

Investigations on some coumarin based corrosion inhibitors for mild steel in aqueous acidic medium: Electrochemical, surface morphological, density functional theory and Monte Carlo simulation approach

Two coumarin derivatives, namely, 3-(3-benzyl-4-hydroxy-2-thioxo-3,4-dihydro-2H-1,3-thiazin-6-yl)-8-methoxy-2H-chromen-2-one (BTMC) and 3-(3-benzyl-4-hydroxy-2 thioxo-3,4-dihydro-2H-1,3-thiazin-6-yl)-2H-chromen-2-one (BTC) were synthesized, characterized and applied as potential corrosion inhibitors for mild steel (MS) in molar hydrochloric acid (1M HCl). Different techniques including Potentiodynamic Polarization (PDP), Electrochemical Impedance Spectroscopy (EIS) and weight loss (WL) measurements were applied in order to prove the inhibition potential of BTMC and BTC against mild steel corrosion. PDP investigation suggests the mixed mode of inhibition by the studied coumarin derivatives. These compounds prevented the metal from corrosive attack of chloride anions (Cl−) by getting adsorbed on the metal surface following Langmuir isotherm adsorption model. The change in surface morphology was studied by Scanning Electron Microscopy (SEM) and Electron Dispersion Spectroscopy (EDS). Organic molecules formed a non-crystalline protective layer on the metal surface which was confirmed from X-ray Diffraction Analysis (XRD).The corrosive solution applied for descaling or acid pickling process dissolved the metal surface, until the inhibitor was not applied. The UV–Vis spectrum confirms the formation of a complex between the inhibitor and the iron cations present in the electrolytic medium. WL measurement revealed that BTMC and BTC exhibit a high inhibition efficiency (IE%) of 93.59% and 92.17% for BTMC and BTC, respectively, in their optimum concentration (300 ppm) at 298 K. Density Functional Theory (DFT) calculations and Monte Carlo (MC) simulations were employed to envisage the interactions of synthesized inhibitors with metal surface along with corrosive species as it happens in corrosive environment. In addition, The Fukui function and local softness indices were computed for the determination of the most plausible nucleophilic and electrophilic attack sites.

Degradation of Losartan in Fresh Urine by Sonochemical and Photochemical Advanced Oxidation Processes

In this work, the degradation of the pharmaceutical losartan, in simulated fresh urine (which was considered because urine is the main excretion route for this compound) by sonochemistry and UVC/H2O2 individually, was studied. Initially, special attention was paid to the degrading action of the processes. Then, theoretical analyses on Fukui function indices, to determine electron-rich regions on the pharmaceutical susceptible to attacks by the hydroxyl radical, were performed. Afterward, the ability of the processes to mineralize losartan and remove the phyto-toxicity was tested. It was found that in the sonochemical treatment, hydroxyl radicals played the main degrading role. In turn, in UVC/H2O2, both the light and hydroxyl radical eliminated the target contaminant. The sonochemical system showed the lowest interference for the elimination of losartan in the fresh urine. It was established that atoms in the imidazole of the contaminant were the moieties most prone to primary transformations by radicals. This was coincident with the initial degradation products coming from the processes action. Although both processes exhibited low mineralizing ability toward losartan, the sonochemical treatment converted losartan into nonphytotoxic products. This research presents relevant results on the elimination of a representative pharmaceutical in fresh urine by two advanced oxidation processes.

DFT computations and molecular dynamics investigations on conformers of some pyrazinamide derivatives as corrosion inhibitors for aluminum

The corrosion inhibition performance of conformers of some selected pyrazinamide derivatives was investigated using density functional theory (DFT) and molecular dynamics simulations. Miscellaneous global and local chemical reactivity descriptors were calculated and correlated to the inhibition efficiency such as the highest occupied molecular orbital energy (HOMO), the lowest unoccupied molecular orbital energy (LUMO), the energy gap (∆Egap), ionization energy (I), electron affinity (A), dipole moment (μ), absolute hardness (η), absolute electronegativity, absolute softness (σ) and the fraction of electron transferred (ΔN). The Fukui function and local softness indices were computed for the determination of the most plausible nucleophilic and electrophilic attack sites. Overall, our results pointed out that the inhibition performance correlates well with the calculated quantum chemical parameters.The adsorption of pyrazinamide derivatives on the aluminum surface was modeled to unravel the adsorption mechanism which involves mainly established covalent AlO bonds as a determinant factor corroborating thus the observed ranking of the inhibition efficiency trend.

Molecular modeling of anionic and cationic dyes adsorption on sludge derived activated carbon

The work deals with the adsorption of two dyes, namely Food Red 17 (FR17) and Methyl Violet (MV), onto a sludge derived activated carbon (SDAC). An experimental analysis of adsorbent properties is preliminary carried out, in order to determine its chemical and textural properties. Subsequently, a molecular simulation analysis based on the reviewed TPSS density functional is performed for the calculation of the molecular structure and properties of both SDAC and the two dyes, as well as for the determinations of their interaction parameters and chemical reactivity descriptors. The nucleophilic and electrophilic attacks within active sites are related to the Fukui function indices and the dual descriptor f (r). A comparison between the descriptors calculated through vertical energy values and those arising from the Koopmans' theorem approximation are performed in order to check for the validity of the procedure. The simulations results show that, although FR17 showed a better affinity with SDAC according to the interaction energy calculations, MV was adsorbed more efficiently than FR17 on SDAC, which was demonstrated by the HOMO–LUMO energies and by the retrieved optimized molecular conformation during adsorption of each dye on SDAC.

Computational prediction of bioactivity scores and chemical reactivity properties of the Parasin I therapeutic peptide of marine origin through the calculation of global and local conceptual DFT descriptors

Eight density functionals, CAM-B3LYP, $$\hbox {LC-}\omega \hbox {PBE}$$ , M11, MN12SX, N12SX, $$\omega \hbox {B97}$$ , $$\omega \hbox {B97X}$$ , and $$\omega \hbox {B97XD}$$ , related to the Def2TZVP basis sets, were assessed together with the SMD solvation model for the calculation of the molecular properties and structure of the therapeutic peptide of marine origin Parasin I. All the chemical reactivity descriptors for the system are calculated via conceptual density functional theory (CDFT). The active sites suitable for nucleophilic, electrophilic, and radical attacks are selected by linking them with the Fukui function indices, nucleophilic and electrophilic Parr functions, and condensed dual descriptor $$\Delta {f(r)}$$ , respectively. The study reveals that the MN12SX and N12SX density functionals are the most appropriate ones for predicting the chemical reactivity of the molecule under study. Additionally, the pKa value for the peptide is predicted with great accuracy based on our previously published methodology. Moreover, the ability of the studied molecule in acting as an efficient inhibitor of the formation of advanced glycation endproducts (AGEs), which constitutes a useful knowledge for the development of drugs for fighting diabetes, Alzheimer and Parkinson diseases is also presented. Finally, the bioactivity scores for Parasin I are predicted through different methodologies.

X-ray and DFT Investigation of (E)-4-bromo-5-methoxy-2-((o-tolylimino)methyl)phenol Compound

(E)-4-bromo-5-methoxy-2-((o-tolylimino)methyl)phenol was investigated by experimental and theoretical methodologies. The solid state molecular structure was determined by X-ray diffraction method. All theoretical calculations were performed by density functional theory (DFT) method by using B3LYP/6-31G(d,p) basis set. The titled compound showed the preference of enol form, as supported by X-ray diffraction method. The geometric and molecular properties were compaired for both enol-imine and keto-amine forms for title compound. Stability of the molecule arises from hyperconjugative interactions, charge delocalization and intramolecular hydrogen bond has been analyzed using natural bond orbital (NBO) analysis. Mulliken population method and natural population analysis (NPA) have been studied. Also, condensed Fukui function and relative nucleophilicity indices calculated from charges obtained with orbital charge calculation methods (NPA). Molecular electrostatic potential (MEP) and non linear optical (NLO) properties are also examined.

Light-dependent isomeric effects of polycyclic aromatic hydrocarbons on the predication of DNA cleavage factor efficiency

PAHs, short for polycyclic aromatic hydrocarbons, are a ubiquitous group of chemically related, environmentally persistent organic compounds having diverse structures and varied toxicity. They have been shown to cause mutagenic and carcinogenic effects on organisms and are quite immunosuppressive. Time-dependent density functional theory (TD-DFT) offers a practical means of understanding the behavior of excitation energies for PAHs. Here, we examined the performance of the long-range corrected Coulomb-attenuating functional (CAM-B3LYP) in relation to four different basis sets, determining which basis set compliments the functional better in identifying the most reactive atomic site on six isomeric PAH compounds. Condensed Fukui function indices were used to compare the performance of applied basis sets in identifying the most reactive atomic site on six isomeric PAHs compounds, assessing which basis set would be more appropriate in determining the site where free-radical formation would occur after light irradiation. Dunning’s correlation consistent triple-zeta (cc-pVTZ) basis set was determined to have the best PAH characterization performance, concluding the need for application of a higher-level basis set with the long-range corrected Coulomb-attenuating functional. Although each compound was a structural isomer of the other, the reactive atomic sites varied for each molecule with the use of an applied basis set. It was concluded that structural shape has some influence on the calculation of PAH characteristics. Lastly, in order to predict DNA single-stranded cleavage factor for the compounds proposed here, we have used the quantitative structure-activity relationship (QSAR). The cleavage factor values for the set of aromatic molecules with similar structures have been collected from the literature for a total number of 22 compounds.

Corrosion Inhibition of Copper in 2M Nitric Acid Solution by 2-(Thiobenzyl)-5-Nitro-1H-Benzimidazole

Pickling with nitric acid is commonly practiced in industry for finishing metal surfaces. The use of inhibitors during the pickling operation is of very recent origin. The TBNBI inhibition effect on copper corrosion in 2M nitric acid solution was investigated by weight loss method in relation to the temperature (25 to 40°C) and inhibitor concentration range 10-4 to 5.10-3 M. The results show that TBNBI is a good inhibitor for copper and the inhibition efficiency increases with concentration of TBNBI but decreases with increase in temperature. The adsorption parameters (ΔGa0ds ,ΔHa0ds ,ΔSa0ds ) and the activation ones * * a a a (E ,ΔH ,ΔS ) for the corrosion process in inhibited and uninhibited nitric acid solution were also calculated using Arrhenius equations. It can be concluded that the adsorption of the compound is spontaneous and found to occur through both physisorption and chemisorption processes. The adsorbed film on copper surface was characterized using optic microscopy and Raman spectroscopy. The surface analysis confirmed the inhibition action of TBNBI. Quantum chemical calculations using Gaussian 09 at B3LYP level with 6-31G (d,p) basis set lead to obtain molecular descriptors such as EHOMO (energy of the highest occupied molecular orbital), ELUMO (energy of the lowest unoccupied molecular orbital), ΔE (energy gap) and μ (dipole moment). The global reactivity descriptors such as χ (electronegativity), η (hardness), S (softness) and ω (electrophilicity index) were derived using Koopman’s theorem and analyzed. We used the condensed Fukui function and softness indices, Mulliken population analysis for local reactivity study. The calculated results are consistent with the experimental data.

Chemical Reactivity Properties, pKa Values, AGEs Inhibitor Abilities and Bioactivity Scores of the Mirabamides A⁻H Peptides of Marine Origin Studied by Means of Conceptual DFT.

The MN12SX density functional, in connection with the Def2TZVP basis set, was assessed, together with the SMD solvation model (Solvation Model based on the Density), for calculation of the molecular properties and structure of a group of peptides of marine origin named Mirabamides A–H. All the chemical reactivity descriptors for the systems were calculated via Conceptual Density Functional Theory (CDFT). The active sites suitable for nucleophilic, electrophilic, and radical attacks were chosen by linking them with the Fukui function indices, nucleophilic and electrophilic Parr functions, and condensed Dual Descriptor , respectively. Additionally, the p values for the different peptides are predicted with great accuracy as well as the ability of the studied molecule in acting as an efficient inhibitor of the formation of Advanced Glycation Endproducts (AGEs), which constitutes a useful knowledge for the development of drugs for fighting Diabetes, Alzheimer and Parkinson diseases. Finally, the bioactivity scores for the Mirabamides A–H are predicted through different methodologies.

Local Molecular Reactivity of the Colored Dansylglycine in Water and Dioxane Studied through Conceptual DFT

This study evaluated a fixed long-range corrected range-separated hybrid (RSH) density functional associated with the Def2TZVP basis set alongside the SMD solvation model for the computation of the structure, molecular properties, and chemical reactivity of the M8 intermediate melanoidin pigment in the presence of water and dioxane. The preference of the active sites pertinent to radical, nucleophilic, and electrophilic attacks is made through linking them with the electrophilic and nucleophilic Parr functions, Fukui function indices, and condensed dual descriptor which are chemical reactivity descriptors that arise from conceptual density functional theory. The study confirmed the results from previous works showing that the MN12SX density functional is the most appropriate in predicting the chemical reactivity of this molecule in both solvents.

Blue M2: an intermediate melanoidin studied via conceptual DFT.

In this computational study, ten density functionals, viz. CAM-B3LYP, LC-ω PBE, M11, M11L, MN12L, MN12SX, N12, N12SX, ω B97X, and ω B97XD, related to the Def2TZVP basis sets, are assessed together with the SMD solvation model for calculation of the molecular properties and structure of blue-M2 intermediate melanoidin pigment. All the chemical reactivity descriptors for the system are calculated via conceptual density functional theory (DFT). The active sites suitable for nucleophilic, electrophilic, and radical attacks are selected by linking them with the Fukui function indices, electrophilic Parr functions, and condensed dual descriptors Δf(r), respectively. The prediction of the maximum absorption wavelength is considerably accurate relative to its experimental value. The study reveals that the MN12SX and N12SX density functionals are the most appropriate density functionals for predicting the chemical reactivity of the molecule under study.

Conceptual DFT study of the local chemical reactivity of the dilysyldipyrrolones A and B intermediate melanoidins

This computational study assessed 11 density functionals related to Def2TZVP basis sets, namely CAM-B3LYP, LC- $$\omega $$ PBE, M11, M11L, MN12L, MN12SX, N12, N12SX, $$\omega $$ B97, $$\omega $$ B97X, and $$\omega $$ B97XD, and the SMD solvation model for calculating the molecular properties and structures of the intermediate melanoidin pigments, dilysyldipyrrolone A (XL-W1) and dilysyldipyrrolone B (XL-W2). The global and local chemical reactivity descriptors for the systems were calculated via conceptual density functional theory (DFT). The active sites applicable to nucleophilic, electrophilic, and radical attacks were chosen by connecting them with Fukui function indices, electrophilic Parr functions, and condensed dual descriptor $$\varDelta {f}({\mathbf {r}})$$ over the atomic sites. The predicted maximum absorption wavelength obtained directly from the HOMO–LUMO was more accurate relative to the experimental values of the MN12SX and N12SX density functionals than those obtained with TDDFT calculations. This study found the MN12SX and N12SX density functionals to be most appropriate for predicting the chemical reactivity of the molecules under study.

Molecular Reactivity and Absorption Properties of Melanoidin Blue-G1 through Conceptual DFT.

This computational study presents the assessment of eleven density functionals that include CAM-B3LYP, LC-wPBE, M11, M11L, MN12L, MN12SX, N12, N12SX, wB97, wB97X and wB97XD related to the Def2TZVP basis sets together with the Solvation Model Density (SMD) solvation model in calculating the molecular properties and structure of the Blue-G1 intermediate melanoidin pigment. The chemical reactivity descriptors for the system are calculated via the conceptual Density Functional Theory (DFT). The choice of the active sites related to the nucleophilic, electrophilic, as well as radical attacks is made by linking them with the Fukui function indices, the electrophilic Parr functions and the condensed dual descriptor f. The prediction of the maximum absorption wavelength tends to be considerably accurate relative to its experimental value. The study found the MN12SX and N12SX density functionals to be the most appropriate density functionals in predicting the chemical reactivity of the studied molecule.

Chemical Reactivity Theory (CRT) Study of the Melanoidin M8: Local Conceptual Density Functional Theory Descriptors

This study evaluated a fixed long-range corrected range-separated hybrid (RSH) density functional associated with the Def2TZVP basis set alongside the Solvation Model based on Density (SMD) for the computation of the structure, molecular properties and chemical reactivity of the M8 intermediate melanoidin pigment. The preference of the active sites pertinent to radical, nucleophilic and electrophilic attacks is made through linking them with the electrophilic and nucleophilic Parr functions, Fukui function indices, and condensed Dual Descriptor. This study showed that the MN12SX density functional is the most suitable one for predicting the chemical reactivity of this system.

Molecular Modeling of the Structures, Properties and Glycating Power of Some Reducing Disaccharides

The molecular structures properties and glycating power of some reducing disaccharides Cellobiose Gentiobiose Isomaltose Lactose Laminaribiose Maltose Mannobiose and Xylobiose have been studied by resorting to Chemical Reactivity Theory including Conceptual DFT and Molecular Electron Density Theory MEDT The reactivity sites for nucleophilic and electrophilic attacks have been chosen by relating them to the Fukui function indices the condensed dual descriptor f r and the Parr functions The glycating power of the reducing disaccharides is compared with that of simple hexoses and pentoses through the values of the calculated reactivity descriptors