Fukui Analysis Research Articles

Vibrational, theoretical characterisation and In Silico investigation of Norcinnamolaurine: a natural lead for inhibiting AURKA and overcoming immune evasion in Triple-Negative Breast Cancer

ABSTRACT Alkaloids represent a diverse category of natural compounds with noteworthy pharmacological and therapeutic applications. Benzylisoquinoline alkaloids (BIAs) are distinguished by their varied structures and potential medicinal properties. This study specifically investigates Norcinnamolaurine, a BIA found in multiple species and acknowledged for its therapeutic advantages. In the current investigation, we comprehensively analyzed Norcinnamolaurine, encompassing Frontier Molecular Orbital studies, vibrational spectroscopy, nonlinear optical properties, natural bond orbital evaluations, and Fukui's analysis. Additionally, we executed an E-pharmacophore-based screening utilizing the AURKA-Norcinnamolaurine complex. The generated hypothesis underwent database screening; lead compounds from the Natural Product and Drug Bank databases exhibited enhanced binding affinities ranging from −8.602 to −7.148 kcal/mol, demonstrating improved interactions within the AURKA binding pocket. Subsequently, the identified lead compounds were subjected to further analysis via MMGBSA, DFT, and Molecular Dynamics Simulations (MDS). Our findings indicate that Norcinnamolaurine exhibits a superior binding affinity towards the target protein. Significant outcomes were also observed in the vibrational and FMO studies. Moreover, MDS analysis revealed that the resultant complexes maintained relative stability, exhibiting minimal deviation and fluctuations. This stability was corroborated through additional assessments using MMPBSA and PCA/FEL methodologies.

Deciphering the molecular complexity: Employing density functional theory to probe 2-aminopyridinium 4-methyl benzene sulfonate elucidates synthesis methodologies, spectroscopic trends, reactivity patterns, molecular dynamics, and antibacterial properties

Harnessing computational modeling with density functional theory (DFT) and the B3LYP functional, delved into molecular geometry, harmonic spectra, and vibrational spectra for 2-aminopyridinium 4-methylbenzene sulfonate (2AP4MBS). Leveraging VEDA software to conduct a detailed investigation into oscillation spectra, particularly focusing on both quantitative and qualitative facets of infrared (IR) and Raman spectra. Our work also explored natural bonding orbitals, Fukui analysis, RDG analysis, and net Mulliken charge calculations, hinting at potential charge transfer within the molecule. Experimental validation of UV–Vis spectroscopic analyses was conducted. Electron density homology surface mapping via electrostatic potential interface (ESP) revealed insights into size, shape, charge density distribution, and reactivity sites. Topological features were elucidated through ELF and LOL maps.Docking simulations shed light on binding energy and interactions with peptide molecules, offering potential pharmaceutical applications following Lipinski criteria and ADMET framework assessments.

MnO2/TiO2-Catalyzed ozonolysis: enhancing Pentachlorophenol degradation and understanding intermediates

Pentachlorophenol is a pesticide widely known for its harmful effects on sewage, causing harm to the environment. In previous studies, our group identified adsorption as a crucial factor in catalytic ozonation processes, and subsequent observations revealed the catalyst’s role in reducing toxicity during degradation. In this research, we quantified organochlorine intermediates and low molecular weight organic acids generated under optimal pH conditions (pH 9), with and without the catalyst. Additionally, we assessed the reactivity of these intermediates through theoretical calculations. Our findings indicate that the catalyst reduces the duration of intermediates. Additionally, the presence of CO2 suggests enhanced mineralization of pentachlorophenol, a process notably facilitated by the catalyst. Theoretical calculations, such as Fukui analysis, offer insights into potential pathways for the dechlorination of aromatic molecules by radicals like OH, indicating the significance of this pathway.

Evaluating the efficacy of newly synthesized amino acid derivatives as corrosion inhibitors in acidic solutions

Three benzimidazole derivatives, with tryptophan (BIT), tyrosine (BIY), and histidine (BIH) amino acid units, have remarkable protective properties as eco-friendly corrosion inhibitors for steel under severe acidic conditions. At a temperature of 303 K, the corrosion inhibition efficiency of BIT, BIY, and BIH at a concentration of 10 mM is 90.09 %, 92.53 %, and 93.43 %, respectively. Electrochemical tests indicate that the adsorption of these substances on the substrate leads to an increase in charge transfer resistance and interfacial electric double layer thickness. This effectively hinders the dissolution of metal and the evolution of hydrogen. The analysis of the surface structure and appearance using SEM-EDS indicates that the inhibitors have the ability to create a protective coating through both chemical and physical bonding, effectively protecting the metal from corrosive substances. Theoretical calculations, such as Density Functional Theory (DFT) and Natural Bond Orbital (NBO) analysis, along with FUKUI analysis, help identify active sites and adsorption configuration. This enhances our understanding of the corrosion mitigation mechanism. These findings align with the experimental conclusion that the formation of a stable protective film contributes to superior inhibition performance against acidic corrosion conditions.

Synthesis, spectroscopic analysis (FT-IR, FT-Raman, UV, NMR), non-covalent interactions (RDG, IGM) and dynamic simulation on Bis(8‑hydroxy quinoline) salicylate salicylic acid

Using spectrum techniques and density functional theory (DFT) reckonings, structural, vibrational and electrical characteristics of Bis(8‑hydroxy quinoline) salicylate salicylic acid (8HQSA) were determined. Characterizing the chemical under inquiry involved employing FT-IR, FT-Raman, UV–vis spectral studies and single crystal X-ray diffraction (SCXRD). For the characterization, the B3LYP approach inside the structure of DFT was employed, with a 6–311++G(d,p) basis set. The structural study shows that the stability of 8HQSA crystalline structure arising from N–H⋯O, C–O⋯H and O–H⋯O hydrogen bonding interactions. The 1H and 13C NMR chemical shifts were calculated using Gauge Independent Atomic Orbital (GIAO) technical. Vibrational frequencies and molecular geometry were computed and likened with experimental data. Here, non-covalent interactions were deeply analyzed in terms of topological parameters (AIM), electron localization function (ELF), localized orbital locator (LOL), Hirshfeld surface and reduced density gradient (RDG) method. Weak interactions such as H-bonds, van der Waals and steric effect in 8HQSA were visualized and quantified by the independent gradient density (IGM) based on the trimolecular density. The hyper-conjugative and the delocalization of charge in 8HQSA have been elucidated by natural bonding orbital (NBO) while its chemical reactivity was studied and discussed by using molecular electrostatic potential surface (MEP), frontier molecular orbital (FMOs), density of state (DOS) and partial density of state (PDOS). The positions of the molecule's nucleophilic and electrophilic groups were ascertained using Fukui analysis. To describe the size, structure, and reactive sites of the molecules, the molecular electrostatic potential and total electron density are calculated. With a band gap (2.58 eV), FMO study indicates that the material is both bioactive and stable. The ADMET factor and drug similarity are used to predict 8HQSA's pharmokinetic characteristics. Based on the findings, it can be concluded that the 8HQSA particle is optimally crystallised and recommended as a preventative measure against bacterial and fungal infections. The stability of the title compound has been investigated via molecular dynamics simulations. In-vitro antimicrobial activity results clearly reveal that in all the four strains, activity increases with increase in compound concentration and the inhibition of the strains also increases. From both molecular docking and In-vitro Antimicrobial Activity the title compound can be certified that it inhibits antimicrobial activity.

Vibrational spectra, molecular structure, electronic, pharmaceutical and bonding nature of (4S)-4-(3,4-dihydroxyphenyl)-1,2,3,4-tetrahydroisoquinoline-7,8-diol - anti hypertension agent

Several factors, including environment, behaviours, and heredity, influence the development of hypertension. The title compound dopamine D1 receptor agonist named (4S)-4-(3,4-dihydroxyphenyl)-1,2,3,4-tetrahydroisoquinoline-7,8-diol (4S4D4T) is one of the most important neurotransmitters associated with numerous neural disorders. Using DFT and quantum chemical simulations, the vibrational, electrical, and structural possessions of the heading compound were predicted. To carry out the quantum computational investigations, a highly compatible method entitled B3LYP basis set was adopted. Vibrational Modes of functional groups with PED values were calculated using VEDA software to compute geometric dimensions and assign fundamental vibrations. Using gas and solvent phases, MEP differentiates between nucleophilic and electrophilic sites and creates distribution for the charge of the molecules. The observed wavelength with (TDSCF) UV–Vis spectra for the various solvents phases were compared. The NBO approach provides an understanding of the electron delocalization that results from hyperconjugation. FUKUI analysis is used to determine the area of site reaction. Electron density's topological analysis was carried out using the QTAIM theory. The ADME (Absorption, Distribution, Metabolism, Excretion) profiles are produced with the Swiss ADME online tool. In summary, this dissertation offers a thorough examination that evaluates the impact of particular pharmaceuticals on solvation and enzyme efficiency using a combination of spectral and quantitative computing methodologies. Therefore, plans for further research can profit immensely by the information gathered. The results of protein-ligand docking using the Auto Dock method with various proteins suggest that the molecule has pharmaceutical properties against receptors.

An experimental and computational exploration on noncovalent interactions, spectroscopic and nonlinear optical properties of novel creatininium cyanoacetate single crystal

A novel creatininium cyanoacetate (CCA) single crystal is synthesized by the slow evaporation technique and characterized by various experimental techniques such as FT-IR, FT-Raman and UV–visible spectral methods. Similar techniques are also investigated by the computational methods using Gaussian 09 software. The structural parameters, natural bond orbital (NBO), frontier molecular orbital (FMO), molecular electrostatic potential (MEP) and nonlinear optical (NLO) investigations are performed utilizing the DFT method with B3LYP/6-311G(d,p) basis set. The polarizable continuum model (PCM) has been used to identify the effect of various solvents (DMSO, ethanol, methanol, water) on the energy gap, excitation and NLO properties of CCA molecule. Fukui analysis is performed to identify the sites prone to nucleophilic and electrophilic attacks. Different topological methods including electron localization function (ELF), localized orbital locator (LOL), independent gradient model (IGM) and interaction region indicator (IRI) has been performed to quantify the noncovalent interaction and to analyse the weak interaction region. The UV–visible analysis indicates that the CCA crystal was optically transparent and has lower cut-off wavelength. The hole-electron analysis is performed to identify the characteristics of six excitations. The third-order NLO activity of the CCA compound is performed using the Z-scan technique and is compared with some related NLO materials. The substantial NLO response suggests that the CCA molecule can be significant for its utilization in advanced NLO applications.

Structural, electronic, intermolecular interaction, reactivity, vibrational spectroscopy, charge transfer, Hirshfeld surface analysis, pharmacological and hydropathy plot on 5-Bromo nicotinic acid – Antiviral study (Hepatitis A, B, and C)

The therapeutic properties of 5-Bromonicotinatic acid (5BNA) were studied for antiviral illnesses like Hepatitis A, Hepatitis B and Hepatitis C and the influence of electron-donating and electron-withdrawing properties of functional groups on the nicotinic acid was evaluated and represented in this study using the DFT approach. The molecular parameters were determined for both gases as well as for various solvent phases. The reactive areas in the compound are examined utilising Fukui analysis. The molecular interactions are accomplished by recognising the different types of bonding found in the compound using the AIM, ELF, LOL, RDG and IRI. Solvation investigations were demonstrated to have an influence on molecular orbital energy, ESP, UV–Vis and NLO analyses. Electron-hole, NBO and Hirshfeld investigations are used to investigate the transfer of charges and interactions inside the molecule. The method of vibrational spectroscopy (IR and Raman) is used to differentiate and identify the various types of vibrations displayed by the compound. The hydropathy plots for the proteins 2A4O, 6CWD and 2OC8 associated with Hepatitis A, Hepatitis B and Hepatitis C illustrate the disquiet and attraction of the amino acids towards the water.

Computational Study on Piperazine‐1,4‐Diium Acetate Using Dft Investigations: Structural Aspects, Topological and Nonlinear Optical Properties

AbstractThe work aims to investigate the nonlinear optical (NLO) activity of piperazine‐1,4‐diium acetate (PAA) molecule utilizing computational techniques. The computational calculations are performed using density functional theory (DFT) to explore the vibrational modes, electronic and NLO properties of PAA by comparing them with piperazine and acetic acid molecules. The natural bond orbital analysis is performed to identify hydrogen bonding and charge transfer interaction. A vibrational analysis is carried out and the assignment of fundamental modes is done using the vibrational energy distribution analysis (VEDA) program. Molecular electrostatic potential, frontier molecular orbital, electron localization function, localized orbital locator and Fukui analysis are carried out to identify chemical reactivity and charge transfer interaction. The UV–visible analysis is performed to obtain the electronic absorption spectrum. The hole–electron analysis is performed for the first five excitations to identify the type of excitation. The atoms in molecules, reduced density gradient and independent gradient model are performed to identify the hydrogen bonding, steric and van der Waals interactions. Hirshfeld analysis is performed to explore the intermolecular interactions within the PAA molecule. The NLO calculation is performed to evaluate the NLO parameters. The obtained results show that the PAA molecule is suitable for NLO applications.

Theoretical investigation on the structural properties, scavenging mechanism and toxicological profile of Nymphaeol C, a flavanone in Macaranga Tanarius

The quantum chemical calculations of Nymphaeol C (C30H36O6) have been carried out using the density functional theory method, M06-2X in the 6-311+G (d, p) basis set. The HOMO, LUMO, molecular electrostatic potential, and physicochemical descriptors of the optimized structure have been evaluated at the same level of theory. Further, this study was designed to evaluate and compare the radical scavenging activity of Nymphaeol C in different solvent media using three potential working mechanisms. The results showed that Nymphaeol C can act as a good antioxidant molecule and it can be better understood by high-ELF localization domain population analysis, atoms in molecules analysis, non-covalent interaction analysis, Fukui analysis, and aromaticity indices evaluated by using the Multiwfn software package. Bond energy is an important concept to evaluate the potency of chemical bonds. The active antioxidant site in the title compound can be predicted more accurately. The molecule displays good drug-like characteristics, as expected by the examination of absorption, distribution, metabolism, excretion, and toxicity.

Synthesis, structural characterization by experimental and theoretical approaches of a new hydrazine derivative Schiff base compound

In this work, 6,6′-((1E,1′E)-hydrazine-1,2-diylidenebis(methanylylidene))bis(3,4-dimethoxyphenol), C18H20N2O6, which is a new symmetrical hydrazine derivative Schiff base compound was synthesized and characterized by elemental analysis, such as FT-IR and Raman, UV-Vis, NMR (1H and 13C) spectroscopies. In addition, the title compound’s thermal behavior was analyzed using TG/DTA techniques. The structure was determined by the X-ray diffraction (XRD) technique performed on a single crystal. Besides, computational methods were performed with the Density Functional Theory (DFT)/B3LYP method using the 6-311++G(d,p) basis set. The UV-Vis, chemical shifts for NMR, harmonic vibrational frequencies, infrared intensities, and Raman scattering activities in the ground state were performed same levels of theory. Intra- and inter-molecular interactions were determined using HS analysis. On the other hand, nucleophilic and electrophilic interactions were investigated using MEP and Fukui analysis. The experimental and computational results were compared comprehensively. To be able to examine the binding pattern of the compound with the PDB ID: 3BPF inhibitor targets were determined computationally by molecular docking studies. And also, HOMO and LUMO analysis, Mulliken and natural charge analysis, thermodynamic and non-linear optical properties were determined.

Effect of solvents on intra- and inter-molecular interactions of oligothiophenes.

Oligothiophenes have long been used as model compounds to understand the chemistry of polythiophenes. Herein, we have some quantum chemical calculations and intra- and inter-molecular interaction calculations of a series of oligothiophenes such as terthiophene, quintetthiophene, sevensthiophene, terthiophene-terthiophene, terthiophene-water, terthiophene-methanol, and terthiophene-chloroform performed by time-dependent density functional theory (TD-DFT), density functional theory (DFT), and Multiwfn: a multifunctional wavefunction analyzer. The UV-vis spectra, HOMO-LUMO energies, NBO analysis, MEP, molecular structures, and electronic properties were computed using DFT/TD-DFT at the level of B3LYP/6-31+ G (d,p) and described. The nature of molecular interactions between terthiophene and solvents like water, methanol, and chloroform were also investigated using non-covalent interaction index (NCI), reduced density gradient (RDG), localized orbital locator (LOL), and electron localization function (ELF) topological analyses. Besides, Fukui functions and energy of population density-of-states were computed using the same method. The calculation results show that there are some changes in the terthiophene with the addition of solvent to the medium. DFT calculations were performed using the Gaussian 09 software and GaussView 5.0 visulation program. Multiwfn software is used to calculate the reduced density gradient (RDG) scatterplots, non-covalent interactions (NCI), ELF, LOL, Fukui analysis, and energy of population density-of-states of oligothiophenes.

Experimental and theoretical vibrational spectral Investigations, structural conformations, DFT estimations and docking studies of antibacterial drug Nitrilotriaceticacid

Nitrilotriaceticacid (NTA) was utilised without additional purification after being bought from Sigma Aldrich Chemical Company in powdered form with 99% purity. Density Functional Theory calculations at B3LYP with a 6-311++G (d,p) level were performed to gain knowledge of molecule geometries, harmonic vibrational spectra, and molecular docking analysis. Vibrational spectral investigations have been carried out with the aid of Normal Coordinate Analysis on the basis of potential energy distribution (PED) of each mode, which helps us to attain a quantitative as well as qualitative analysis of IR and Raman spectra followed by empirical scaled quantum mechanical force field methodology. Natural bond orbital analysis, Fukui analysis, RDG analysis, and Mulliken’s net charges have also been predicted. FMO's energy gap predicts the occurrence of charge transport within molecule. UV–Visible spectral analyses of NTA have been examined by experimental and theoretical calculations. By mapping electron density isosurface with an electrostatic potential surface (ESP), information about the size, shape, charge density distribution, and site of chemical reactivity of the molecules has been acquired. ELF and LOL maps portrayed topological aspects of NTA which also have been depicted. Hyperpolarizability values are in good agreement revealing that these compounds could be employed in electro optical applications. Antibacterial activity reveals that NTA have been found to exhibit antibacterial effects. Docking simulation has been carried out for the optimized ligand molecule to identify binding energy and coupling with protein molecule. NTA molecule underwent a drug likeness test utilising Lipinski's criterion, and using ADMET contour, the molecule is recommended for inclusion in pharmaceuticals.

AsCCAs]-Coordinated Rhenium Hydrides and Their Reactivities Toward Unsaturated Hydrocarbons, Heterocumulenes, and CO2.

An [AsCCAs] ligand featuring a central alkyne and two flanking arsenic donors was employed for the synthesis of a trihydrido rhenium complex, while the corresponding phosphorus ligand was shown to be less suited. The reactivity of the former trihydride [AsCCAs]ReH3 (3) was examined in detail, which revealed that two alternative reaction channels may be entered in dependence of the substrate. Upon reaction of 3 with PhC≡CPh, ethylene, and CS2, monohydrides of the general formula [AsCCAs]Re(L)H with L = η2-PhC≡CPh (4), η2-H2C═CH2 (5), and η2-CS2 (6) were formed along with H2. In contrast, insertion products of the type [AsCCAs]Re(X)H2 (7-9) were obtained upon treatment of 3 with CyN═C═NCy, PhN═C═O, and Ph2C═C═O, while CO2 failed to react with 3 under identical reaction conditions. Given that several productive reactions between CO2 and hydrido rhenium carbonyls have been reported in the literature, 3 was further derivatized by introducing CO and tBuNC coligands, respectively. This led to the isolation of trans-[AsCCAs]ReH(CO)2 (trans-10) and trans-[AsCCAs]ReH(CNtBu)2 (trans-11), which were shown to thermally isomerize to the corresponding cis-configured products, cis-10 and cis-11. Interestingly, only the cis-complexes were found to react with CO2, which was rationalized by evaluating the relative nucleophilicities of the hydrides in cis-10, trans-10, cis-11, and trans-11 via Fukui analysis. The formates cis-[AsCCAs]Re(OCHO)(CO)2 (12) and cis-[AsCCAs]Re(OCHO)(CNtBu)2 (13) were isolated and shown to contain κ1-O-coordinated formate moieties. Treatment of 12 with [LutH]Cl/B(C6F5)3 (or with Ph3SiCl) led to the liberation of [LutH][OCHO···B(C6F5)3] (or triphenylsilyl formate) with concomitant formation of the expected chloro complex cis-[AsCCAs]ReCl(CO)2 (14). In a closed synthetic cycle, hydride 12 was regenerated from the latter chloride using NaBEt3H as a hydride source.

Investigation of the crystal structure, supramolecular architecture and in-silico myelofibrosis inhibition of a triazole derivative: a structural and theoretical approach

One of the most significant issues in contemporary medicine and pharmacy is the search for efficient, low-toxic anticancer medicines. In this contrast, present work involves the synthesis of 6-(4-bromophenyl)-3-(pyridin-4-yl)-7H-[1,2,4]triazolo[3,4-b[1,3,4]thiadiazine compound and its characterization using various spectroscopic techniques. Structural and Hirshfeld surface analysis inferred that the crystal packing is stabilized by several intra and intermolecular interactions, their nature and strength are corroborated by the quantum theory of atoms in molecules analysis. The H···H and C-H···N strong intra and intermolecular hydrogen bond interactions resulted in the formation of S(5), S(6) self-motifs and R22(10), R66(42) supramolecular ring motifs. Further, the electronic properties of the molecule were obtained using the density functional theory. The charge distribution on the molecular surface are analyzed using the molecular electrostatic potential map and Fukui analysis. The intramolecular hyper conjugations, and charge delocalization in the compound are analyzed by natural bond orbital analysis. The docking studies revealed that the molecule might possess potential anticancer activity against Janus tyrosine kinase 2 protein compared to pacritinib, and in silico ADMET pharmacokinetic properties indicate adherence to Lipinski's rule of five for favorable safety profiles.

Understanding Antioxidant Abilities of Dihydroxybenzenes: Local and Global Electron Transfer Properties

In the current work, globally based on Koopmans’ approximation, local electron transport characteristics of dihydroxybenzenes have been examined using the density functional theory for understanding their antioxidant activity. Our experimental and theoretical studies show that hydroquinone has better antioxidant activities when compared to resorcinol and catechol. To identify the antioxidant sites for each dihydroxybenzene molecule, an average analytical Fukui analysis was used. The typical Fukui analytical results demonstrate that dihydroxybenzene oxygen atoms serve as antioxidant sites. The experimental and theoretical results are in good agreement with each other; therefore, our results are reliable.

Synthesis, Spectroscopic (FTIR, FT-Raman and UV-Vis), Structural Investigation, Hirshfeld, AIM, NBO, Chemical Reactivity, In-Vitro and In-Silico Analysis of N-(2-Hydroxyphenyl)-4-Toluenesulfonamide

The prospective antimicrobial molecule N-(2-Hydroxyphenyl)-4-methylbenzene sulfonamide has been synthesized and characterized by single crystal XRD, FT-IR, FT-Raman, UV-Vis spectra and antimicrobial analysis. The quantum chemical computations of energies, geometrical structure, charge transfer and vibrational wavenumbers were carried out using density functional method (DFT/B3LYP) with 6-311 G (d, p) basis set. The complete vibrational assignment for the vibrational modes were performed with vibrational energy distribution analysis (VEDA4) and these assignments were compared with the experimental FT-IR and FT-Raman spectrum. In FT-IR spectrum, strong intense absorption bands are observed at 3408 and 3273 cm−1 corresponding to OH and NH group, which is involved in N–H…O and C–H…O intermolecular interaction. Hirshfeld surface analysis determines the stability of crystal packing within the crystal packing ensured by C–H…O and O–H…O intermolecular interactions. The 2 D fingerprint plot shows that H…H, C…H and O…H interaction exhibit the most significant contribution. Natural bond orbital (NBO) analysis suggests that the electronic transitions are mainly attributed to π→π* transitions. The strength of N–H…O and C–H…O intermolecular interactions were analyzed using reduced density gradient (RDG) analysis and atom in molecule (AIM) analysis. The frontier molecular orbital analysis reveals the possibility of charge transfer within the molecule. Electrophilic and nucleophilic sites were found by molecular electrostatic potential (MEP) analysis and Fukui analysis. Molecular docking shows that sulfonamide and hydroxyl groups are biologically active through their hydrogen bonding interaction with amino acids, which reveals the antimicrobial activity of the compound. Antimicrobial activity of the compound was confirmed by the Kirby Bauer disk diffusion method. The band gap energy and antimicrobial evaluation of the title molecule were compared with the reported relative compounds, which reveals the significant antimicrobial activity. Besides, drug likeness and ADMET (absorption, distribution, metabolism, excretion and toxicity) prediction analysis suggest that the title compound can be used as an antimicrobial drug.

Structural insights, spectral, flourescence, Z-scan, C-H…O/N-H…O hydrogen bonding and AIM, RDG, ELF, LOL, FUKUI analysis, NLO activity of N-2(Methoxy phenyl) acetamide

Quantum chemical calculations of geometries and vibrational wavenumbers of N-2(methoxy phenyl)acetamide(N2MPA) in the ground state were carried out by using density functional theory (DFT/B3LYP) method with 6-31G (d,p) basis set. The scaled harmonic vibrational frequencies have been compared with experimental FT-IR spectra. Theoretical vibrational spectra of the title compound were interpreted by means of potential energy distributions (PEDs) using MOLVIB program. The experimental 1H and 13C NMR chemical shifts were investigated and then compared with computed NMR data using the gauge – invariant atomic orbital (GIAO) method. The optical nature of the grown crystal was evaluated by using the UV-Vis optical transmittance spectrum. The lower wavelength absorption range and various optical constant for instance, energy band gap, absorption and extinction coefficient, refractive index, susceptibility and Urbach energy values were evaluated. The colourless crystal of N2MPA was grown by slow-evaporation technique. The nonlinear optical (NLO) properties of N2MPA have been investigated using Z-scan technique. The emission behavior of N2MPA was analyzed by fluorescence spectral analysis. Thermal stability of N2MPA was studied by TG-DTA analysis. The HOMO and LUMO energy levels are constructed and the corresponding frontier energy gaps are determined to realize the charge transfer within the molecule. The molecular electrostatic potential(MESP), natural bond orbital(NBO) analysis and topological analysis such as electron localization function(ELF), reduced density gradient(RDG), localized orbital locator(LOL), atoms in molecule(AIM) and FUKUI function analysis have been used to evaluate the intermolecular interaction, especially the hydrogen bonds. Fingerprint plots of Hirshfeld surfaces were used to locate and analyze the percentage of hydrogen bonding interactions.

Interaction between organic molecules and a gold nanoparticle: a quantum chemical topological analysis

The ligands at the surface of a gold nanoparticle (GNP) have a significant influence on the optical and physical properties, that may render different functionalities to the GNP. Therefore, there is a need in understanding the nature of the interaction at atomic resolution in order to allow rational design of GNPs with desired physico-chemical properties. The interaction between Au $$_{79}$$ and a series of small organic molecules has been systematically studied at the quantum mechanical level : methane, methanol, formic acid, hydrogen sulfide, benzene, and ammonia. The reactivity of Au $$_{79}$$ has been first analyzed by performing the condensed Fukui analysis to emphasize that the surface of Au $$_{79}$$ is dominated by electrophilic sites, with higher reactivity at the corner and edge atoms. The net charge transfer flowing from the organic molecules toward Au $$_{79}$$ comes from the electrophilic behavior of the GNP. Furthermore, the shape of the frontier molecular orbitals of Au $$_{79}$$ and of the incoming organic molecules has been found to dictate the preferred orientation of the adsorption. Several quantum chemical topological analyses of the electron density have been performed to further classify the interactions to weak dispersive or van der Waals interactions in methane and stronger non-covalent interactions in ammonia, benzene, hydrogen sulfide, methanol, and formic acid. The analysis of the electron localization function (ELF), on the other hand, provides more insight about the charge transfer, as the population of the basins of the organic molecules has decreased after interacting with Au $$_{79}$$ .

Quantum computational investigations and molecular docking studies on amentoflavone

Chagas disease is a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi, with approximately 6–7 million people infected worldwide, becoming a public health problem in tropical countries, thus generating an increasing demand for the development of more effective drugs, due to the low efficiency of the existing drugs. Aiming at the development of a new antichagasic pharmacological tool, the density functional theory was used to calculate the reactivity descriptors of amentoflavone, a biflavonoid with proven anti-trypanosomal activity in vitro, as well as to perform a study of interactions with the enzyme cruzain, an enzyme key in the evolutionary process of T-cruzi. Structural properties (in solvents with different values of dielectric constant), the infrared spectrum, the frontier orbitals, Fukui analysis, thermodynamic properties were the parameters calculated from DFT method with the monomeric structure of the apigenin used for comparison. Furthermore, molecular docking studies were performed to assess the potential use of this biflavonoid as a pharmacological antichagasic tool. The frontier orbitals (HOMO-LUMO) study to find the band gap of compound has been extended to calculate electron affinity, ionization energy, electronegativity electrophilicity index, chemical potential, global chemical hardness and global chemical softness to study the chemical behaviour of compound. The optimized structure was subjected to molecular Docking to characterize the interaction between amentoflavone and cruzain enzyme, a classic pharmacological target for substances with anti-gas activity, where significant interactions were observed with amino acid residues from each one's catalytic sites enzyme. These results suggest that amentoflavone has the potential to interfere with the enzymatic activity of cruzain, thus being an indicative of being a promising antichagasic agent.