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• A diversity of novel annulated pyrido[2,3- d ]pyrimidines were synthesized. • DFT calculations using B3LYP/6–311++ G (d,p) basis set support the experimental data. • Molecular reactive sites were discovered using MEP and Fukui functions. • The ADME analysis and molecular docking were carried out. • In vitro anticancer efficiency was examined. 6-Amino-1,3-dimethyluracil (1) has two electron donating centres (NH 2 and C-5) and its chemical reactivity was investigated towards a variety of electrophilic reagents hoping to construct some novel heteroannulated pyrido[2,3- d ]pyrimidines. The key precursor 1 reacted with some o -chloroaldehydes through condensation between activated C-5 and the formyl group followed by heterocyclization with elimination of HCl. Also, reaction of compound 1 with some o -aminoaldehydes occurred through a similar mechanism. In addition, reaction of precursor 1 with some arylidenes took place through addition of C-5 to the activated double bond followed by cycloaddition of the amino group onto the cyano function with concomitant aromatization. The synthesized compounds were characterized using spectroscopic techniques and evaluated for in vitro anticancer activity against HepG-2 cell lines where compound 4 was found to be the most potent (IC 50 =3.99 µM). The optimized structures, HOMO-LUMO energies and chemical reactivity descriptors of the synthesized compounds were computed by density functional theory (DFT) calculations using the B3LYP/6–311++ G (d,p) basis set. Compound 13 has the lowest energy gap (2.90 eV) and therefore is more the reactive and polarizable than other compounds. The sites for electrostatic interactions are identified using molecular electrostatic potential (MEP). The frequencies calculated by FT-IR showed good agreement with those derived from the experimental findings. Theoretical 1H and 13C NMR chemical shift values were calculated using GIAO method and compared with experimental values using linear correlation factor (R2). Moreover, the nucleophilic and electrophilic reactive sites were probed by Fukui functions accompanying the optimized structures using DFT. The first hyperpolarizabilities (β tot) of the prepared compounds are higher than the reference urea; indicating good nonlinear optical properties and are excellent materials for NLO applications. All the current compounds adhered to the Lipinski, Veber and Ghose rules that were a set of parameters used in ADME studies. In addition, the binding interactions of the synthesized compounds were investigated by molecular docking studies with aromatase enzymatic protein (PDB id: 31G7) receptor and correlated with anticancer activity. [Display omitted] [ABSTRACT FROM AUTHOR]

The goal of this study is to look at the development and use of green inhibitors in the electropolishing process (EP), as well as their potential as an anti-corrosive coating for C-steel in an acidic medium. We can replace environmentally dangerous substances with inexpensive, effective molecules that have little or no negative environmental impact like amino acids which are employed as safe inhibitors. The EP characteristics of C-steel were measured by galvanostatic techniques with different concentrations of amino acids over a wide range of (1-1000 × 10−6 mol/l) and temperatures (298–313 K). The findings indicate that the electropolishing behavior of C-steel is governed by mass transfer, with Fe2+ being proposed as the governing species for the salt film mechanism during anodic dissolution in the limiting current plateau. The experimental results indicate that increases in the amino acid concentrations inhibit the EP by 83.33% in the case of L-Methionine at 298 K. Density Functional Theory (DFT) was used to optimize geometry in the gas and liquid phases. The inhibition efficiency was associated with global reactivity descriptors, Fukui indices and dual local descriptors. The inhibitory performance is in good agreement with the estimated quantum chemical parameters, according to our findings. [ABSTRACT FROM AUTHOR]

• Thirteen N,N -disubstituted chloroacetamides were synthesized as covalent inhibitors • Several chloroacetamides effectively activated both extrinsic and intrinsic apoptotic pathways • 3D QSAR and pharmacophoric similarity search suggested alcohol-metabolizing enzymes as promising targets • Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) identified as potential anticancer targets through pharmacophoric similarity search. • Docking studies demonstrated hydrogen bonds and hydrophobic interactions with ADH and ALDH. The recent FDA approval of afatanib, ibrutinib, and osimertinib, which covalently bind to specific cysteine residues in target kinases, has renewed interest in covalent drug discovery. Besides α,β -unsaturated carbonyls, chloroacetamides have emerged as popular warheads for designing targeted covalent inhibitors. In this study, we synthesized thirteen N,N -disubstituted chloroacetamides (1 – 13) by acylating secondary amines with chloroacetyl chloride, selecting substituents to provide a wide range of lipophilicity. We evaluated their anticancer and antimicrobial activity, finding five compounds with significant cytotoxicity against HeLa, K562, and A549 cell lines (IC 50 <10 μM). Notably, compound 10 activated caspases 3, 8, and 9, promoting both intrinsic and extrinsic apoptotic pathways, while compounds 9 – 12 were strong apoptosis inducers. A 3D QSAR model showed that aromatic substituents on nitrogen atoms reduced HeLa potency, whereas the overall molecular shape had a positive effect. ChemBL and pharmacophoric similarity searches suggested potential anticancer targets, including alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), glycogen synthase kinase-3β, and calmodulin. Docking studies indicated that chloroacetamides bind to ADH and ALDH via hydrogen bonds and hydrophobic interactions. Pharmacokinetics predictions suggest that chloroacetamides are druglike molecules with promising ADMET properties. [ABSTRACT FROM AUTHOR]

• The reactivity of substrate 3 was investigated towards binucleophiles. • Chromone moieties are more reactive than α,β-unsaturated ketone segment. • DFT/B3LYP/6-311G++(d,p) was used to discuss theoretical calculations. • ADME analysis and molecular docking studies were assessed. • The NMR were estimated theoretically and well-matched with experimental results. The electron deficient centers in α,β-unsaturated ketone 3 are C-2 and C=O of chromone moieties as well as C=O and H-β of α,β-unsaturated ketone segment. To investigate the reactivity of various electron deficient centers and to synthesize some heterocyclic systems, compound 3 was allowed to react with some binucleophilic reagents. The antimicrobial activity of some compounds showed a notable inhibitory effect on the microorganisms that were being studied. The synthesized compounds were verified by spectral and analytical data. The structure of the prepared compounds were optimized at the DFT/B3LYP level of theory employing 6-311G(d,p). Density Functional Theory (DFT) was used to compute the chemical reactivity descriptors. Compound 9 is more stable and less reactive than other compounds. MEP mapping was applied at the same computational level to identify the favored locations for electrophilic and nucleophilic assault, providing additional insight into the regioselectivity in the desired reaction. Moreover, the most reactive sites of compound 3 were investigated by Fukui function descriptor using Mulliken charges. The 13C and 1H-NMR spectra of the prepared compound were measured experimentally in DMSO, and correlated with the theoretical calculations that performed by 6-311G(d,p) of DFT-B3LYP method. All compounds met Veber's and Lipinski's requirements according to in silico predictions made with the SwissADME online server, suggesting the possibility for usage as oral active drugs. The synthesized compounds were also subjected to molecular docking studies to investigate their binding pattern and affinity for the CDKs active site and correlated with antimicrobial data. [ABSTRACT FROM AUTHOR]

• Experimental and theoretical spectral investigation of dihydro-pyrimidines. • Experimental and theoretical Fourier transform infrared (FT-IR) spectra were recorded and compared. • Experimental and theoretical IRaman were also calculated and compared. • A benchmark analysis was performed by employing DFT functions by estimating HOMO to LUMO UV transitions, band gaps (eV) and oscillator strength φ by comparing with experimental λ max. Theoretical 1H and 13C NMR chemical shift values. • In addition, Muliken charges, natural population analysis (NPA), fukui functions, and thermodynamic parameters were calculated. In this article, theoretical and experimental study is presented for eight derivatives of dihydro-pyrimidinones (symbolized as U1-U6, U10 and U11). The Fourier transform infrared (FT-IR) spectra of dihydro-pyrimidinones were recorded in the range of 4000cm−1 to 400cm−1 in solid phase and compared with experimental vibrational assignments. The potential energy distributions (PED) was assigned to each scaled vibrational wavenumber value by using Vibrational Energy Distribution Analysis (VEDA4) program. In order to get insight into electronic properties and a good UV absorber compound Time Dependent Density Functional Theory (TF-DFT) approach was taken into consideration. A benchmark analysis was performed by employing DFT functional B3LYP, HSEH1PBE, MPW1PW91, WB97XD by estimating HOMO to LUMO UV transitions, band gaps (eV) and oscillator strength φ by comparing with experimental λ max. Theoretical 1H and 13C NMR chemical shift was calculated using GIAO method and compared with already published experimental NMR chemical shift values by using linear correlation factor R2. Electron poor, rich and reactive sites were probed by Mulliken atomic charge, natural population analysis (NPA) and fukui functions accompanying the optimized structures by utilizing density functional theory (DFT) methods with B3LYP function and 6–311 G (d, p) as basis set. In last vibrational assignments were subjected to thermodynamic parameter calculations using Moltran v.2.5. program. [Display omitted] [ABSTRACT FROM AUTHOR]

This work presents a significant investigation involving both electrochemical experiment and quantum chemical simulation approaches. The objective was to characterize the electrochemical detection of dopamine (DA). The detection was carried out using a modified carbon paste electrode (CPE) incorporating bentonite (Bent) and l -cysteine (CySH) (named as CySH/Bent/CPE). To understand and explain the oxidation mechanism of DA on the CySH/Bent modified electrode surface, the coupling of the two approaches were exploited. The CySH/Bent/CPE showed excellent electroactivity toward DA such as good sensibility, selectivity, stability, and regenerative ability. The developed sensor shows a dynamic linear range from 0.8 to 80 μM with a limit of detection and quantification of 0.5 μM and 1.5 μM, respectively. During the quantitative analysis of DA in presence of ascorbic acid (AA) and uric acid (UA) the electrochemical oxidation signals of AA, DA, and UA distinctly appear as three separate peaks. The potential differences between the peaks are 190 mv, 150 mv, and 340 mV for the AA–DA, DA–UA, and AA–UA oxidation pairs, respectively. These observations stem from square wave voltammetry (SWV) studies, along with the corresponding redox peak potential separations. The developed sensor is simple and accurate to monitor DA in human serum samples. On the other hand, CySH acts as an electrocatalyst on the CySH/Bent/CPE surface by increasing its active electron transfer sites, as suggested by the quantum chemical modeling with analytical results of Fukui. Furthermore, the voltammetric results obtained agree well with the theoretical calculations. [Display omitted] • Electrochemical experiments and quantum chemical simulations were performed. • Bent and CySH were employed to modify CPE. • The device is simple and precise to monitor DA in serum. • The analytical results from Fukui suggests that CySH acts as an electrocatalyst. • The sensor showed excellent response to DA with an LOD of 0.5 μM. [ABSTRACT FROM AUTHOR]

[Display omitted] • Theoretical calculations of N -substituted triazolonitroindazoles were performed. • GIAO Approach was used and CDFT reactivity indices were defined. • Fukui functions and relative nucleophilicity indices were calculated. • MEP Surface was investigated. • Potential application of N -substituted triazolonitroindazoles in optoelectronics and photonics. The reaction of 5-nitroindazole with 1,2-dibromoethane gave N -bromoethyl-5-nitroindazole and N -vinyl-5-nitroindazole. N -Bromoethyl-5-nitroindazole was used as a precursor to synthesize N -substituted triazolonitroindazoles (NST1-NST4) through copper-catalyzed azide-alkyne cycloaddition (CuAAC). In this study, we investigated the reactivity indices of N -substituted triazolonitroindazoles defined within the conceptual DFT framework: chemical hardness, electronic affinity, ionization potential, and electronic chemical potential. Fukui functions as well as relative nucleophilicity indices were calculated using Mulliken calculation methods. The 1H NMR chemical shifts of NST1-NST4 were computed and compared to the experimental values. The theoretical UV visible spectroscopic and Fourier transform infrared studies were performed to define the absorption band and the functional groups for each compound. Nonlinear optical descriptors (NLO) specifically dipole moment, polarizability, first-order and second-order hyperpolarizability were also defined. According to the results, NST4 has the lowest hyperpolarizability, making it the most stable and exhibiting a weak NLO response. In contrast, NST3 displays the uppermost hyperpolarizability, making it the least stable with a high NLO response being a promising candidate for NLO-devices. [ABSTRACT FROM AUTHOR]

• The mechanism of asphalt aging was analyzed using Frontier Molecular Orbital, Fukui Functions, Density Functional Theory. • The mechanism of ageing-resistant agents improving asphalt aging was analyzed by Fukui Functions. • The correctness of quantum chemical calculation is proved through experiments, which provides an effective method for study on the aging mechanism of asphalt and improving the anti-aging performance of asphalt. To investigate the effect of ·OH radicals on asphalt Aromatics aging, density functional theory was utilized to calculate the Gibbs free energy, reaction energy barrier, and temperature associated with asphalt aromatic decomposition, thermal oxygen aging, and UV aging. To study chemical structural activity, Frontier Orbitals theory and Fukui Functions were employed to determine Frontier Molecular Orbitals and Fukui Index. The findings reveal that the activity of aromatic compounds is primarily concentrated near the naphthalene ring, which is prone to etherification reactions. The alkyl activity of aromatic compounds is quite low, rendering them less susceptible to nucleophilic, electrophilic, and radicals' reactions. One reason for thermal oxygen aging of asphalt is the direct interaction between asphalt molecules and O 2. On the other hand, UV aging occurs due to the splitting of O 2 into ·O radicals, which in turn generate ·OH radicals which can oxidize asphalt. The results of quantum chemical calculations were cross-validated by infrared spectroscopy IR, SARA, and GPC methods. IR spectroscopy analysis showed that thermal and ultraviolet aging would increase carbonyl and benzene derivatives in aromatic compounds, while thermal aging would not increase hydroxyl groups. SARA further confirmed that asphalt aging would enhance molecular polarity. GPC confirmed that The molecular weight of asphalt aromatic components increases after aging. This article provides useful experience for using quantum chemistry to study the mechanism of asphalt aging. [ABSTRACT FROM AUTHOR]

• Deciphered the structure of 5-chloro-2-hydroxy-3-methoxybenzaldehyde. • NBO, MESP, Mulliken, and Fukui analyses validated reactive sites. • Conducted topological exploration (ELF, LOL, RDG, NCL, QTAIM). • Molecular docking affirmed the compound's potency as a tumor antagonist. • Conducted experimental and theoretical investigation to confirm the structure. In this study, the benzaldehyde derivative 5-chloro-2-hydroxy-3-methoxybenzaldehyde (5C2H3MB) was characterized using spectroscopic techniques. Geometric parameters and complete fundamental vibrational assignments were simulated using DFT/B3LYP/6-311++G(d,p). The 1H and 13C chemical shifts, computed using the GIAO method, were in agreement with the experimental findings. The electronic properties of 5C2H3MB were analyzed using time-dependent density functional theory (TD-DFT) to determine various electronic parameters, including HOMO-LUMO energies. NBO analysis was performed to determine the numerous hyper-conjugative interactions responsible for the stability of the compound. In addition, Mulliken population analysis and Molecular Electrostatic Potential Surfaces (MESP) analysis were conducted to identify electron-rich, electron-poor, reactive sites, and bonding characteristics of the titled compound. The topological analyses ELF, LOL, NCI, QTAIM, and RDG were performed using Multiwfn software, and global reactivity parameters and Fukui functions were also predicted. Molecular docking studies were conducted to confirm the biological activity by simulating the binding orientation and affinity of 5C2H3MB against transferase inhibitor and human phosphorylated IRE1 alpha, showing a binding energy of −5.1, −5.3 and −5.9 kcal/mol, indicating its potential as an antagonist. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract A molecule 4-chloro-N-(4,5-dihydro-1H-imidazol-2-yl)-6-methoxy-2-methylpyrimidin-5-amine plays a significant role in the treatment of hypertension and acts as a potential I 1 imidazoline receptor agonist. In this present work, the molecular structure of the title compound has been investigated using experimental (FT-IR, FT-Raman and NMR) and theoretical (DFT) techniques. R2 values of FR-IR, FT-Raman and bond lengths state the coherence between theoretical and experimental values. Asymmetric, symmetric stretching and bending vibrations were reported. The geometrical parameters obtained theoretically are in agreement with experimental values. Chemical activity region of the molecule (MEP), molecular stability, charge localization and delocalization (NBO), occupied and unoccupied molecular orbitals (HOMO-LUMO), dipole moment, polarizability and hyperpolarizability (NLO) have been calculated. There is a significant change in a net atomic charge distribution with a corresponding increase in the value of total dipole moment. Furthermore, the mulliken population analysis on atomic charges (electronic properties), thermodynamic parameters at various temperatures have also been calculated. To study the biological activity, different proteins for ligand have been taken and the results suggest that the compound might exhibit anti-hypertensive activity. Henceforth, Quantum mechanical calculations have been done for the title compound to get optimized structure and electronic energies for biological, physical, pharmaceutical and medicinal interest. Graphical abstract Image 1 Highlights • Spectroscopic interpretation of 4NDIM5 has been carried out. • HOMO–LUMO energies and dipole moment have been obtained. • Local reactivity using Fukui function, NBO and MEP diagram were computed and analyzed. • Molecular docking and Drug-likeness were also discussed. [ABSTRACT FROM AUTHOR]

Abstract In this work the 4,6-dichloro-2-(methylsulfonyl)pyrimidine (DCMSP) has been synthesized from 4,6-dichloro-2-(methylthio)pyrimidine, its molecular and electronic structure was authenticated by detailed spectroscopic signature studies (via SCXRD, FT-Raman, FT-IR and (1H &13C) NMR), Hirshfeld surface analysis and DFT calculations. The solid-state crystal structure of DCMSP corroborated by the single crystal X-ray diffraction studies, features C H⋯O and π···π interactions. Quantum chemical calculations of DCMSP have been performed at DFT/B3LYP/6-311++G (d,p) level of theory. The detailed assignment of each the vibrational mode was done on the basis of potential energy distribution (PED) by using the VEDA4 program and these results have been correlated with the experimental data. We calculated the linear and nonlinear optical properties of the title compound to understand the linear and nonlinear optical behavior in both static and dynamic fields using an iterative electrostatic embedding scheme and density functional theory (DFT) methods with standard and long-range corrected functionals. We also performed a study of the linear refractive index and nonlinear optical susceptibility χ(3) of the crystal as a function of frequency. An estimate of linear and nonlinear macroscopic quantities confirms their suitability for nonlinear optical devices such as optical limiting and optical switching. Investigation of local and global reactivity parameters of DCMSP was carried out by the calculation of molecular electrostatic potential (MEP), average local ionization energies (ALIE) surfaces and atomic Fukui indices in the gas phase. Stability in water and sensitivity towards autoxidation process has been investigated by radial distribution function (RDF) and bond dissociation energies (BDE) calculation after molecular dynamic simulations. Graphical abstract Image 1 Highlights • Most reactive sites are identified by using MEP and ALIE plots. • Autoxidation and degradation properties are investigated from BDE and RDF calculations. • DCMSP crystal exhibit potential candidate for application in nonlinear optical devices. • A detailed interpretation of FT-IR and FT-Raman spectra of DCMSP reported. [ABSTRACT FROM AUTHOR]

Graphical abstract The aromaticity of fluorine-substituted uracil is larger than uracil, because the 2 p z electrons of F atoms participated in the formation the π bond of the uracil ring. The E 2 value associated with C F bond indicate that 5-FU is more active than 6-FU. Highlights • Fluorine substitution strategies are essential in drug design. • As an antitumor agent, 5-FU is more active than 6-FU. • The C5 atom connected with F is more susceptible to electrophilic attack. • The introduction of F into uracil rings can improve the aromaticity. Abstract An investigation was conducted of Fluorine-substituted uracils (5-fluorouracil, 6-fluorouracil and 5, 6-difluoro-uracil) at the B3LYP [6-311G(d, p)/6-311+G(d, p)/6-311++G(d, p)] levels. A calculation was performed of their equilibrium structures and harmonic frequencies in gas and water. A combination of C F binding energies, Natural bond orbital (NBO), reactivity descriptors, Fukui functions, and aromaticity was applied to figure out the impact made by the numbers and location of fluorine atoms on the structural parameters, infrared spectrum, active site and aromaticity of the uracil. In this paper, a systematic research is carried out into the similarities and differences between fluorine-substituted at 5-position of uracil and 6-position. The outcomes are expected to provide a theoretical guidance with regard to the development of the fluoridated drugs. [ABSTRACT FROM AUTHOR]

Abstract The work involves the vibrational spectral analysis of 2.6 bis (tri fluro methyl) benzoic acid using FT-IR and FT-Raman spectroscopy. The computations were performed at DFT level of theory to get the optimized geometry and vibrational wave numbers of the normal modes of the title compound using Gaussian software. The detailed vibrational assignments were proposed on the basis of potential energy distribution. The calculated HOMO and LUMO energies show chemical activity of the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The hyperpolarizability values are also reported. From the MEP plot, the negative electrostatic potential regions are mainly localized over the oxygen atoms and the positive regions are localized over all the hydrogen atoms. Fukui functions are calculated to find the possible sites for electrophilic and nucleophilic attack. Graphical abstract The work involves the vibrational spectral analysis of 2.6 Bis (tri fluro methyl) benzoic acid. The theoretical calculations were performed at DFT level of theory with 6–311++g(d,p) as basis set. A visual representation of molecular orbital composition was done using DOS. Image Highlights • The spectroscopic investigations of 2,6 bis (trifluro methyl) benzoic acid were carried out using HF and B3LYP methods. • Normal coordinate analysis was performed. • HOMO-LUMO energy calculations show the charge transfer within the molecule. [ABSTRACT FROM AUTHOR]

A new non-ionic organic coumarin-based surfactant was synthesized and applied to the surface of the steel in 1.0 M HCl solution. The response of the steel surface to the corrosion suppression was probed by measuring polarization, impedance, and frequency modulation in different concentrations (0.5 × 10−4 M to 7.5 × 10−4 M). While fitting the experiments to different adsorption isotherms, the steel-inhibitor interface interacted according to the Langmuir model. The maximum efficiencies of 84.18 % and 97.93 % were obtained for the inhibitor's lowest and highest concentrations, respectively based on the impedance spectroscopy measurements. The inhibitor was able to combat the anodic and cathodic reactions simultaneously showing a mixed-type inhibition ability. The free energy ΔG ads was calculated to be from −36.75 to – 38.62 kJ/mol based on the Langmuire model, indicating chemical adsorption on steel surface. A narrow energy gap of 3.012 eV was predicted by DFT calculations in consistency with high inhibition efficiency. The molecular reactivity was attributed to the contiguous system of many π orbitals on naphthalene, chromone, thiazole, and diazene entities. In turn, the p-electrons of the oxaheptadecane chains exhibit a lower contribution to the adsorption of the surfactant on the metal surface. New experimental and theoretical insights were derived and related to corrosion inhibition. [Display omitted] • A novel nonionic surfactant was synthesized and utilized as a corrosion inhibitor. • The corrosion inhibition was analyzed using Wl, EFM, EIS, and PDP. • Surface convergence was confirmed by SEM and AFM analysis. • Fukui function, MD, MC, FMO, and NBO analyses showed effective electron compensation to the corroded metal. [ABSTRACT FROM AUTHOR]

Abstract The (E)‑1‑(3, 5 dibromo benzylidene) semicarbazide (35DBBS) has been synthesized and characterized using Fourier-transform infrared (FT-IR), Fourier transform Raman (FT-Raman), 1H and 13C Nuclear magnetic resonance (NMR) spectral analyzes. Fukui functions, molecular electrostatic potential (MEP), bond dissociation energies (BDE) and average local ionization energy (ALIE) values have been studied with help of Density Functional Theory (DFT). Further, the stability of 35DBBS in water has been analyzed using molecular dynamics (MD) simulations. The optimized molecular geometrical parameters such as bond length, bond angle and dihedral angle were calculated in different phases viz., gaseous and aqueous and were compared with experimental values. The title compound's binding energy and antifungal ability of the title compound were evaluated using molecular docking studies. Further, Nonlinear Optical Properties (NLO) of 35DBBS have been examined by first order hyperpolarizability studies. Graphical abstract Unlabelled Image Highlights • (E)‑1‑(3, 5 dibromo benzylidene) semicarbazide has been synthesized. • Results of MD simulations, BDE and MEP revealed diverse applicability of 35DBBS. • Docking studies brought to light the biological activity. • Higher β and lower HOMO-LUMO values of 35DBBS confirmed NLO activity. [ABSTRACT FROM AUTHOR]

Abstract Mitoxantrone (MX) is an important antineoplastic drug used for treatment of different types of cancer with lower side effects. The purpose of this study is to shade more light on the mechanism of interaction between MX and biological molecules. This study would result in drug design and development. Molecular structure was computed at the B3LYP/6-31 + G(d) level. All possible intramolecular hydrogen bonding interactions were considered and calculated at the same level. Five conformers of MX were located and computed to lie in the energy range 0.000–48.495 kcal/mol. Molecular reactivity of MX towards biological systems was explored using condensed molecular descriptors, Fukui functions of electrophilic, nucleophilic and free radical attack. Molecular docking studies for the inhibition of CDK2 and DNA binding were carried out to explore the anticancer potency of MX. The role of charge transfer binding in the interaction of MX with biological molecules was investigated via studying the ability of MX to act as a charge transfer acceptor with known donors using NMR spectroscopy. Charge transfer complex formation was confirmed by proton chemical shift and stability constants were measured from the NMR chemical shift data. Stability constants of MX with donors, phenylene diamine, hexamethyl benzene and pyrene are 4.178, 2.527 and 1.240 M-1 respectively. Graphical abstract Image 1 Highlights • Five conformers of MX within the energy range (0.000–48.495 kcal/mol) were studied. • MX is more likely to act as an electophile than being as a nucleophile. • MX acts as an electron acceptor with known charge transfer donors. • Docking results confirm the higher potency of MX compared with other anthraquinones. • Charge transfer force has major role in the interaction of MX with biological systems. [ABSTRACT FROM AUTHOR]

In this paper diethyl (hydroxy(4-methoxyphenyl) methyl) phosphonate has been synthesized and characterized by FTIR, FT-Raman UV–Vis. The structural geometrical parameters, vibrational, electronic, HOMO-LUMO, Fukui analysis, and the thermodynamic properties of the molecule were performed on the basis of DFT calculations at B3LYP/6-311G(d,p) basis set using Gaussian 09 package. Thermogravimetric (TG) analysis was also carried out to study thermal stability of compound. The HOMO-LUMO study to find the band gap of compound has been extended to calculate ionization potential, electron affinity, global hardness, electron chemical potential and global electrophilicity to study the chemical behaviour of compound. A good agreement between observed and calculated wavenumbers has been obtained. The correlations between the statistical thermodynamics and temperature show that increase in temperature increases heat capacities, entropies and enthalpies. [ABSTRACT FROM AUTHOR]

We have set-up an electrochemical advanced oxidation process for ethidium bromide (1), based on the Eu-doped MnWO 4 (Eu:MnWO 4), obtained through a template-driven synthesis, along with developing a suitable monitoring method. Under galvanostatic conditions, Eu:MnWO 4 -coated graphite electrode serves as anode, applicable for removal of 1. To go further and augment the catalytic method, we have applied a modified carbon paste electrode for the monitoring of 1 with the limit of detection (LOD) of 54 nM. Enhancement of the hydrogen evolution reaction is an indication of electrocatalytic properties of the material, whereby developed method emerges as a candidate for straightforward application in electrochemical advanced oxidation processes (EAOPs). We have enriched experimental data with theoretical insights, provided by Density Functional Theory (DFT), and proposed oxidation mechanism of 1. Based on obtained results, we propose the new nanomaterial as a potent electrochemical modifier, suitable for catalytic treatment and process monitoring of the 1 -polluted waters. [Display omitted] • Eu:MnWO 4 -based nanomaterial for ethidium bromide sensing and control. • A novel analytical approach for both ethidium bromide degradation and concentration monitoring. • Ethidium bromide degradation mechanism was studied theoretically. • The practical feasibility of this system was tested by monitoring the treated water parameters. [ABSTRACT FROM AUTHOR]

The experimental FT-IR and FT-Raman spectra of 4 – [(3, 4 –dichlorophenyl) amino] 2 – methylidene 4 – oxo butanoic acid (DMOA) has been recorded. Quantum chemical calculations of geometry and vibrational wavenumbers of the title compound are carried out theoretically and were compared with the experimental results. NBO analysis, HOMO-LUMO, hardness, softness, first hyperpolarizability and molecular electrostatic potential results are also reported. The negative regions of the MEP are related to electrophilic reactivity and the positive regions to nucleophilic reactivity, as shown in the MEP plot and the title compound has several possible sites. Natural bonding orbital (NBO) assessment was completed with a reason to clarify charge transfer, inter hybridization and delocalization of electron density within the molecule. A computation of the first hyperpolarizability of the compound indicates that this class of substituted butanoic acid may be a good candidate as an NLO material. The study is extended to calculate the binding energy of the title compound with suitable protein by Autodock software. The RDG scatter graphs and the RDG gradient isosurface further illustrate that the interactions between DMOA belong to the van der Waals interactions. [ABSTRACT FROM AUTHOR]

In this work, the inclusion complex of DCY/CENS: N -(2-chloroethyl), N -nitroso, N′, N′-dicyclohexylsulfamid and β-cyclodextrin (β-CD) is investigated using the fluorescence spectroscopy, PM3, ONIOM2 and DFT methods. The experimental part reveals that DCY/CENS forms a 1:1 stoichiometric ratio inclusion complex with β-CD. The constant of stability is evaluated using the Benesi-Hildebrand equation. The results of the theoretical optimization showed that the lipophilic fraction of molecule (cyclohexyl group) is inside of β-CD. Accordingly, the Nitroso-Chloroethyl moiety is situated outside the cavity of the macromolecule host. The favorable structure of the optimized complex indicates the existence of weak intermolecular hydrogen bonds and the most important van der Waals (vdW) interactions which are studied on the basis of Natural Bonding Orbital (NBO) analysis. The NBO is employed to compute the electronic donor–acceptor exchanges between drug and β-CD. Furthermore, a detailed topological charge density analysis based on the quantum theory of atoms in molecules (QTAIM), has been accomplished on the most favorable complex using B3LYP/6-31G(d) method. The presence of stabilizing intermolecular hydrogen bonds and van der Waals interactions in the most favorable complex is predicted. Also, the energies of these interactions are estimated with Espinosa's formula. The findings of this investigation reveal that the correlation between the structural parameters and the electronic density is good. Finally, and based on DFT calculations, the reactivity of the interesting molecule in free state was studied and compared with that in the complexed state using chemical potential, global hardness, global softness, electronegativity, electrophilicity and local reactivity descriptors. [ABSTRACT FROM AUTHOR]

A Density Functional Theory (DFT) study using the relativistic effective core potentials (RECPs) is performed with an aim to understand the relative energies and gain deeper insight of the preferential binding of the sites of nucleobases towards particular sites of tetrahedral twenty atom Au and Ag clusters and Au 4 cluster using reactivity descriptors. Such calculations carry high values towards understanding the relativistic effects of the Au atom towards the Surface Enhanced Raman spectrum (SERS) of small molecules like uracil and thymine when they are bound to the heavy metal clusters, viz., Au and Ag. The relative stabilities based on the prediction of the reactivity descriptors are analyzed. For Au 4 , scattering activities exhibit further enhancement in absence of relativistic mass-velocity contractions and Darwin corrections as implemented in LANL2DZ ECPS for Au in complexes, indicating the importance of relativistic effects in Au for proper evaluation of SERS and explains Ag acting as a better surface than Au for SERS. [ABSTRACT FROM AUTHOR]

• A diversity of heterocyclic compounds was synthesized and characterized. • Molecular modeling studies and DFT calculations were performed. • Chemical reactivity was explained with the aid of global and local chemical parameters. • The NLO analysis including dipole moment, polarizability, and hyperpolarizability values were calculated. • Physicochemical and pharmacokinetics properties were studied. The chemical behavior of 3-substituted-6,8-dimethylchromones 1-3 was studied towards two selected nucleophiles namely 1 H -benzimidazol-2-ylacetonitrile (R1) and 5-amino-2,4-dihydro-3 H -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. [Display omitted] [ABSTRACT FROM AUTHOR]

• (3E,3′E)-3,3′-(1,4-phenylenebis(azanediyl))bis(cyclohex-2-en-1-one) is described. • Theoretical 1H and 13C NMR spectra reproduce well the experimental NMR spectra. • The most intense bands in IR and Raman spectra are assigned and discussed. • Stabilization interactions are examined by NBO and QTAIM analyses. • Docking with ADAMST5 protein shows higher binding potential than for native ligand. This article presents the results of the structural and spectroscopic analysis of (3E,3′E)-3,3′-(1,4-phenylenebis(azanediyl))bis(cyclohex-2-en-1-one) by the means of IR, Raman, NMR, and Density functional theory methods. The structure of the compound was optimized at the B3LYP/6-311++G(d,p) level of theory. The NMR spectra were predicted using the Gauge Independent Atomic Orbital approach. The mean absolute differences between experimental and theoretical chemical shifts were 0.44 and 2.3 ppm for 1H and 13C NMR spectra thus proving the applicability of the chosen level of theory. The vibrational (IR and Raman) spectra were assigned based on the optimized structure following the Potential Energy Distribution (PED) analysis. The intermolecular interactions governing the stability of the compound were investigated by the Natural Bond Orbital and Quantum Theory of Atoms in Molecules analyses. The active positions in the compound were assessed by the Fukui functions calculation and Molecular electrostatic potential map. The inhibitory activity of the compound was analyzed by molecular docking toward cartilage proteins. This activity, along with the groups included in interactions, proved the activity of various parts of the molecule. The inhibitory activity was higher than that of a native ligand. The ecotoxicity assessment proved low toxicity towards aquatic organisms. These results show the high potential of enaminone derivatives obtained under mild conditions. [Display omitted] [ABSTRACT FROM AUTHOR]

A series of arylazo pyridone dyes was synthesized by changing the type of the substituent group in the diazo moiety, ranging from strong electron-donating to strong electron-withdrawing groups. The structural and electronic properties of the investigated dyes was calculated at the M062X/6-31 + G(d,p) level of theory. The observed good linear correlations between atomic charges and Hammett σ p constants provided a basis to discuss the transmission of electronic substituent effects through a dye framework. The reactivity of synthesized dyes was tested through their decolorization efficiency in TiO 2 photocatalytic system (Degussa P-25). Quantitative structure-activity relationship analysis revealed a strong correlation between reactivity of investigated dyes and Hammett substituent constants. The reaction was facilitated by electron-withdrawing groups, and retarded by electron-donating ones. Quantum mechanical calculations was used in order to describe the mechanism of the photocatalytic oxidation reactions of investigated dyes and interpret their reactivities within the framework of the Density Functional Theory (DFT). According to DFT based reactivity descriptors, i.e. Fukui functions and local softness, the active site moves from azo nitrogen atom linked to benzene ring to pyridone carbon atom linked to azo bond, going from dyes with electron-donating groups to dyes with electron-withdrawing groups. [ABSTRACT FROM AUTHOR]

Reactive properties of a newly synthesized third generation ionic liquid, namely the 1-butyl-3-methylimidazolium taurate ([BMIM][Tau]), has been investigated employing density functional theory (DFT) calculations. M06-2X exchange-correlation functional with 6-31G +(d,p) basis set was chosen for the geometrical optimizations and calculation of various properties. Global reactive properties have been investigated using molecular orbital theory and quantum molecular descriptors. Dipole moment indicates weaker interactions with water than in the case of our previously investigated [BMIM][Sal] ionic liquid (IL). Further, molecular electrostatic potential (MEP) and averaged local ionization energy (ALIE) surfaces recognized nitrogen atom of [Tau] − and carbon atoms of imidazolium ring to be prone to electrophilic attacks. Fukui functions provided further insight into the local reactivity properties of this IL, indicating that C(9) position of imidazolium ring (in some literature as C2) could be prone to the nucleophilic attacks, while other carbon atoms of imidazolium ring could be prone to electrophilic attacks. Bond dissociation energies (BDEs) have been calculated as well, indicating that S O bond of [Tau] − could be vulnerable to chemical species, however, our previous molecular dynamics results indicate that this part of the molecule has pronounced interaction with water, so the hydrolysis mechanism is more probable. Finally, using all calculated data we summarized reactive properties. [ABSTRACT FROM AUTHOR]

Charge transfer properties and adsorption mechanism of tetracene on silver are investigated based on DFT and SERS. Optimized geometries indicate distortions in hexagonal structure and deviations in co-planarity of carbon atoms due to the variations in bond angles and dihedral angles after adsorption on silver. Natural population analysis (NPA) confirms the charge transfers from silver to tetracene. Natural bond orbital (NBO) analysis illustrates the overlapping of π(C C) and π*(C C) orbitals and that of Ag valence orbitals with π(C C) of tetracene indicating charge transfers consequent to the process of adsorption. Theoretically simulated absorption spectrum has a surface plasmon resonance peak around 520 nm with major contributions arising from the charge transfers from HOMO to LUMO, HOMO-1 to LUMO and HOMO to LUMO + 2 excitations. Theoretically predicted SERS confirms the tilted orientation of tetracene on silver surface and the charge transfers reported. Chemically reactive sites were identified through Fukui functions. Localization of electron density arising from redistribution of electrostatic potential along with the reduction in bandgap of tetracene after adsorption on silver suggests its utility in the design of electro active organic semiconducting devices. Enhancement in dipole moment, polarizability and hyperpolarizability of tetracene after adsorption on silver indicates its potential in the design of novel NLO materials. [ABSTRACT FROM AUTHOR]

Conformational and molecular docking analysis of 2-acetylamino-5-bromo-6-methylpyridine molecule was carried out and the vibrational spectral analysis was also carried out using experimental and theoretical methods. The calculated and experimentally observed vibrational frequencies of the molecule were assigned and compared. The pyridine ring CH stretching and CH 3 stretching vibrational modes were shifted towards higher wavenumber (blue shift). The C=O stretching vibrational frequency was shifted towards lower wavenumber (red shift). Ultraviolet–visible spectrum of the molecule simulated theoretically was further validated experimentally. Molecular reactivity and stability were investigated using the frontier molecular orbital analysis and the related quantum chemical molecular properties. Natural bond orbital analysis and the structure activity relations were also studied to confirm the bioactivity of the molecule. Anticancer activity was examined based on molecular docking analysis and it has been identified that the AABMP molecule can act as a good inhibitor against lung cancer. [ABSTRACT FROM AUTHOR]

A density functional theory (DFT) based method in conjunction with the projector augmented wave and pseudopotential methods have been applied to investigate the adsorption of Pt 4 and Pt 3 Ni on the anatase TiO 2 (1 0 1) surface. Two stable Pt 3 Ni adsorptions with considerable adsorption energies on the anatase TiO 2 (1 0 1) surface were identified. Analysis of the partial density (PDOS) of states and Bader charge suggest that the electronic structure of Pt is modified by Ni due to the electron transfer from Ni to Pt atoms in the Pt 3 Ni clusters. The 2cO (3cO)-PtNi-5cTi conformation of the adsorbed Pt 3 Ni on the anatase TiO 2 (1 0 1) surface provides a more feasible model for electron injection through the Pt 3 Ni/TiO 2 interface. The reactivity of Pt 3 Ni/TiO 2 is superior to Pt 4 /TiO 2 and effectively manifests itself in the eased decomposition of O H bonds derived by methanol and alleviative CO adsorption. [ABSTRACT FROM AUTHOR]

This work presents an experimental and theoretical study to address the chemical reactivity of series of nitroxide radicals. For that purpose two physicochemical properties: the half-wave potential and the hyperfine coupling constants of the nitrogen nuclei, were analyzed. Experimental values are compared with electronic structure calculations at the BHandHLYP/6-311++G(2d,2p) level. E 1/2 values were in good agreement with the adiabatic ionization potential when including the solvent effects by the Cramer and Truhlar Solvation Model. Preeliminar experimental electron spin deslocalization studies suggest that structural hindrance plays an important role in their deslocatization mechanism. [ABSTRACT FROM AUTHOR]

Highlights: [•] The structural, vibrational and reactivity characteristics have been determined. [•] The molecule has great electronegativity difference and charge is highly polarized. [•] The atoms C2, C3, C5, C6, N7, O9 and C10 are more prone to nucleophilic attack. [•] The LUMO of the molecule feature a larger number of nodes than the HOMO. [•] The n N →π* CO interaction possess a strong stabilization of 64.21kcalmol−1. [ABSTRACT FROM AUTHOR]

Highlights: [•] Vibrational analysis of 5-chloro-1-methyl-4-nitroimidazole is carried out. [•] Quantum chemical studies are done by DFT method. [•] The 1H and 13C chemical shifts are analysed. [•] Electronic transitions are investigated by UV–Visible spectrum. [•] The global and local reactivity descriptors are determined. [Copyright &y& Elsevier]

Highlights: [•] Vibrational analysis of N-carbethoxyphthalimide was carried out. [•] Quantum chemical studies were done by DFT method. [•] The 1H and 13C chemical shifts were analysed. [•] The carbonyl carbons C1/C3 and C16 show downfield signal at 163.76 and 148.45ppm. [•] The global and local reactivity descriptors were determined. [ABSTRACT FROM AUTHOR]

Highlights: [•] The optimized geometry and vibrational assignments with PED were computed using DFT methods. [•] The MEP, NBO and HOMO, LUMO energy gap were theoretically predicted. [•] A thermodynamics properties of the title compound was calculated at the different temperatures. [Copyright &y& Elsevier]

Highlights: [•] The structural, vibrational and reactivity characteristics have been determined. [•] Both the molecules have great electronegativity difference, charge is very polarized. [•] The atoms C4, C5 and C6, C7 are more prone to nucleophilic and electrophilic attack. [•] The LUMO of both the molecules feature a larger number of nodes than the HOMO. [•] The HOMO and LUMO orbital energy gap is 5.2948eV for 4BMDO and 4.8951eV for 45BMDO. [ABSTRACT FROM AUTHOR]

Highlights: [•] An approximate method for representation of molecular face is proposed. [•] The MFs for a series of molecules are shown for evaluating the approximate method. [•] The Fukui descriptors on the MFs for haloalkanes and heterocyclics. [•] The MFs of isolated and stacked bases in DNA double helix. [ABSTRACT FROM AUTHOR]

Abstract: The experimental and theoretical study on the structures and vibrations of 2-[(2-hydroxyphenyl) carbonyloxy] benzoic acid (abbreviated as HPCBA) are presented. The FT-IR and FT-Raman spectra of the title compound have been recorded in the region 4000–400cm−1 and 4000–100cm−1 respectively. The molecular structures, vibrational wavenumbers, infrared intensities, Raman activities were calculated using DFT (B3LYP) method with 6-31G(d,p) basis set. The most stable conformer of HPCBA is identified from the computational results. The assignments of the vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field (SQMFF) methodology. Intermolecular hydrogen bonds are discussed in dimer structure of the molecule. The first order hyperpolarizability (β 0) and related properties (β, α 0 and Δα) of HPCBA are calculated. The stability and charge delocalization of the molecule was studied by natural bond orbital (NBO) analysis. The molecule orbital contributions are studied by density of energy states (DOSs). UV–Visible spectrum of the compound was recorded in the region 200–400nm and the electronic properties such as HOMO and LUMO energies were determined by time-dependent TD-DFT approach. Fukui functions, local softness and electrophilicity indices for selected atomic sites of the title compound are determined. Mulliken population analysis on atomic charges is also calculated. Thermodynamic properties (heat capacity, entropy and enthalpy) of the title compound at different temperatures are calculated. [Copyright &y& Elsevier]

Abstract: A simple, efficient, and high yielding one-pot protocol for the synthesis of 2H-indazolo[2,1-b]phthalazine-trione derivatives has been developed by three-component coupling of phthalhydrazide, dimedone and some aromatic aldehydes in ecofriendly neat conditions promoted by nano-γ-alumina sulforic acid. This protocol avoids the use of expensive catalysts, toxic solvents and chromatographic separation. Also the proposed protocol was extended to the linear β-diketone (acetylaceton) instead of cyclic diketone (dimedone). The generality and functional tolerance of this convergent and environmentally benign method is demonstrated. The nature of each step of the suggested mechanism for this condensation reaction is also identified through Density Functional Theory (DFT) calculations using B3LYP/6-31G** level of theory. It is shown that the first step is charge controlled; whereas the second one is controlled by frontier molecular orbitals. The 1H and 13C chemical shift values together with the structural parameters of the title compound have been also computed and the scaled values have been compared with the corresponding experimental NMR and X-ray spectra. As a result, the calculated spectroscopic data and optimized geometry show a good agreement with the experimental results. [Copyright &y& Elsevier]

Quantum chemical approach at B3LYP/6-31G(d,p) level of theory, was used to calculate some structural and electronic properties of three quinoxaline derivatives, recently reported as mild steel corrosion inhibitors in acidic media, to ascertain the correlation between their experimental inhibitive efficiencies and some of the computed parameters. The results of most of the global reactivity descriptors show that the experimental and theoretical studies agree well and confirm that Me-Q=S is a better inhibitor than Q=S and Cl-Q=S, respectively. In addition, the local reactivity, analyzed through Fukui functions, show that the sulphur atom will be the main adsorption site. [Copyright &y& Elsevier]

Abstract: Density functional calculations at the PBE/DNP level have been carried out to investigate the structures, electronic and reactivity properties of Au6H n (n =1–12) clusters. Adsorption of hydrogen atoms stabilizes the Au6 cluster indicated by the high binding energies. The adsorption of H atoms till Au6H6 retains the planar triangular structure of Au6. However, the triangular structure is distorted on further addition of H atoms till Au6H9. In clusters Au6H10, Au6H11 and Au6H12, though the triangular structure is restored but the structures are non-planar. The averaged Hirshfeld atomic charges indicate the H atoms to be negatively charged in all the clusters. Odd–even alternation in HOMO–LUMO gap, chemical hardness, vertical ionization potential, adiabatic ionization potential and binding energy is observed with the clusters having even number of H atoms possessing higher values and are observed to be more stable than their congeners with odd number of H atoms. DFT based reactivity descriptors indicate that in Au6, the Au atoms forming the vertices of the outer triangle have higher relative electrophilicity value while those forming the vertices of the inner triangle have higher relative nucleophilicity value. However, in Au6H6, two nearby Au sites forming the vertices of the inner and outer triangle have the highest relative electrophilicity and relative nucleophilicity values. In Au6H12, these are located in the inner triangle. [Copyright &y& Elsevier]

Abstract: Ozonation of the quinolone antibiotic levofloxacin was investigated with focus on both the levofloxacin degradation rate and degradation product formation. Degradation was about 2 times faster at pH 10 compared to pH 3 and 7 explained by direct ozonation at the unprotonated , one of the tertiary amines of the piperazinyl substituent. H2O2 concentration (2–100μM) had only limited effect. Liquid chromatography – high resolution mass spectrometry revealed degradation at the piperazinyl substituent and the quinolone moiety, with the relative importance of both pathways being strongly affected by changes in pH. Levofloxacin N-oxide concentrations reached up to 40% of the initial levofloxacin concentration during ozonation at pH 10. Degradation at the quinolone moiety resulted in isatin and anthranilic acid type metabolites, probably formed through reaction with hydroxyl radicals. Ab initio molecular orbital calculations predicted radical attack mainly at C2 of the quinolone moiety. This is the carbon atom with the largest Fukui function. Reaction with ozone is expected to mainly occur at , characterized by the largest negative charge. [Copyright &y& Elsevier]

• The UV-Visible spectrum was recorded in ethanol solution and inspected with the TD-DFT technique. • The assignment of vibrational modes evaluated with Potential Energy Distribution (PED) • DFT investigations were executed using B3LYP with basis set 6-311++G(d,p). • Electronic characteristics such as HOMO-LUMO energy states, and NBO studies were evaluated. • Molecular docking study was accomplished with a DNA binding protein of Cellular Tumour Antigen P53. In this investigation, optimization geometry of the molecule, FT-IR, FT-Raman, and UV-Vis spectra, vibrational frequencies, assigning of suitable vibrational modes of Bendamustine (an anti-cancer drug) were summarised on the grounds of distribution of potential energy. Spectroscopic investigations are attempted by employing DFT/B3LYP with 6-311++G (d, p) level. The output of the computations was implemented to model the spectra of the Bendamustine, which agrees well with the recorded spectra. The TDFT had been utilized to compute the strengths of oscillators. To ascertain the transfer of charge inside the molecule HOMO and LUMO analytics have been utilized. The NBO investigation has been employed to verify the stability of the molecule by observing internal charge transfer, hyperconjugation, and energy of stabilization. Molecular electrostatic potential and Mulliken's charges were thoroughly studied by using DFT methods. The NLO characteristics of the title drug molecule were investigated with B3LYP and HF basis functionals. The reactive sites and reactivity of the title drug molecule have been extensively studied with help of condensed Fukui functions and global descriptors. The molecular docking investigations of the title drug molecule were executed with the DNA binding protein of Cellular Tumour Antigen P53. [ABSTRACT FROM AUTHOR]

• DFT method, was carried out in order to investigate the adsorption four phenyltetrazole derivatives on the steel surface. • Molecular dynamics simulation approach was used to predict the type of molecules adsorption. • Cl-Ph-T was adsorbed parallel on the steel surface and its heteroatoms were oriented towards the metallic surface. • Negative values of the adsorption energies attested that adsorption was spontaneous. B3LYP, B3PW91, CAM-B3LYP, HCTH, ωB97XD, and M06-2X are six hybrid correlation-exchange and meta-GGA functionals, with 6-31G(d,p) basis set for the H, C, N, O and Cl atoms and the LANL2DZ basis set for the Fe atom. Utilized to determine the most favorable to be applied with phenyltetrazole derivatives, namely: 5-phenyl-1H-tetrazole (Ph-T), 5-p-tolyl-1H-tetrazole (Me-Ph-T), 5-(4-methoxyphenyl)-1H-tetrazole (Me-O-Ph-T), 5-(4-chlorophenyl)-1H-tetrazole (Me-O-Ph-T), and 5-(4-chlorophenyl) (Cl-Ph-T). Aside from that, the quintet complexes were the most stable of the spin multiplicities studied. Furthermore, three forms of interactions between Fe and phenyltetrazole compounds are identified using Fukui functions, including Fe-Me/Me-O/Cl, Fe-ϕ, and Fe-N among eleven complexes. The meta-GGA functionals are ideally suited to predict metal–ligand interaction in the complexes investigated, which contain the transition metal iron with unsaturated valences. While the bond energies and enthalpies estimated for the two Fe- Me-O-Ph-T and Fe- Cl-Ph-T complexes are the lowest and almost identical, the two inhibitors investigated act similarly. Furthermore, chemisorption is promoted by the flatness of the Cl-Ph-T and Me-O-Ph-T inhibitors. Moreover, the adsorption energy of the Cl-Ph-T and Me-O-Ph-T inhibitors. (-185.661 and −186.005 kcal/mol, respectively), suggests that they are the most stable and strongest adsorption systems demonstrated by MDS. The discovered dynamic descriptors were in excellent accord with the quantum study's findings. [ABSTRACT FROM AUTHOR]

Abstract: A simplified model of the hardness kernel, , has been evaluated for the calculation of the global hardness in a series of Lewis acids and bases using the MP2 method. It is found that this simple model yields the appropriate ordering of the molecules according to their hardness values when compared to experimental available results. [Copyright &y& Elsevier]

Abstract: By using the CHIH-DFT (Density Functional Theory for Heterocyclic Systems) model chemistry, we have calculated some properties related to the reactive behavior, such as the electronegativity, E HOMO, E LUMO, gap energy, hardness, electron affinity and ionization potential, as well as the chemically active sites indicated by Fukui functions of the megazol molecule, an antiparasitic drug particularly effective against trypanosomes. [Copyright &y& Elsevier]

Abstract: A theoretical study of aryl succinic and maleic acid derivatives, which are potent inhibitors on bovine acetylcholinesterase activity, was done by means of using a B3LYP/6-31G(d,p) level. Therefore, the Atoms in Molecules theory was employed to calculate the properties of the critical point such as density, Laplacians, and ellipticities. Furthermore, reactivity descriptors such as local softness were calculated in order to predict the reactive sites in the molecule. These results were corroborated by Laplacian values. The electrophilic attack (high sk-/sk+ value) occurs in the O7′ atom for 1, 2, 4, 6, 7, 8 and 9 as well as in the nitrogen atom for 3 and 5. All ligands are susceptible to nucleophilic attacks in the carbonyl carbon, whether such carbon be ester, amide or imide. In accordance with the theoretical calculations, the lowest electron density is located in these regions. Furthermore, the heteroatoms are susceptible to suffering elecrophilic attack, which leads to the conclusion that the ligand-enzyme recognition is by retro-electron donation. This is confirmed by the energies of the HOMO of the aromatic ring as well as the LUMO of the lateral chains. [Copyright &y& Elsevier]

The regioselectivity for a series of four 1,3-dipolar cycloaddition reactions has been studied using global and local reactivity indexes. The results of the theoretical analysis suggest that for asynchronous cycloadditions associated to polar processes, the regioselectivity is consistently explained by the most favorable two-center interactions between the highest nucleophilic and electrophilic sites of the reagents. [Copyright &y& Elsevier]

Abstract: In this work, we have elucidated the regioselectivity in some Diels–Alder reactions essentially by means of the Hard and Soft Acid Base principle applied locally. On the basis of the Gazquez–Mendez conclusions, we calculated the condensed local softnesses for the terminal atoms in order to show the preferential cyclization mode of these reactions. The results obtained with the B3LYP/6-31G* method confirm the ortho regioselectivity observed experimentally. The regioselectivity of these reactions has also been confirmed by the calculation of the activation energies and by the application of the Houk rule. [Copyright &y& Elsevier]

The ability of the vanadyl pyrophosphate (1 0 0) surface to selectively activate n-butane in the slow step of paraffin oxyfunctionalisation was investigated. Quantum chemical calculations were performed on small cluster models for orthophosphate and pyrophosphate surface terminations. Electrostatic potential surfaces for n-butane and the catalyst clusters show favourable electrostatic interaction, with the reactant oriented to maximise Coulombic attraction between terminal hydrogens and surface oxygens. Site-selectivity for covalent interaction at the reactant–surface interface, as measured by frontier molecular orbital (FMO) surfaces and Fukui functions, indicates that surface vanadium species can selectively cleave methylene C&z.sbnd;H bonds for butane activation. Both surface terminations, orthophosphate and pyrophosphate, feature the same activation mechanism. The pyrophosphate model, however, has a higher concentration of surface P&z.sbnd;O oxygen species which feature prominently in the high-lying occupied orbitals. Hence, the pyrophosphate-terminated surface may promote subsequent controlled oxidation of activated n-butane to maleic anhydride. The susceptibility of maleic anhydride to further reaction at the surface was also examined using the active site reactivity analyses. [Copyright &y& Elsevier]