Frontier Molecular Orbital Analysis Research Articles

Sunlight-activated dye degradation of ZnO/CdO-decorated graphene oxide and its antibacterial activity

The pollution of water sources by hazardous substances such as sulfates, cyanides, and heavy metals represents a major environmental challenge. Addressing these issues requires the degradation of pollutants in wastewater to mitigate our environmental crises. Graphene oxide (GO) significantly enhances the mechanical and functional properties of GO-ZnO and GO-CdO nanocomposites, making them promising materials for applications in both sensors and catalysts. In this context, two optically active metal oxide-decorated graphene oxides (GO-ZnO and GO-CdO) were synthesized, and their photocatalytic efficacy against methylene blue (MB) was evaluated. Using an FT-IR spectrophotometer, the vibrational modes of hydroxyl (OH), carbonyl (C]O), and carboxylic (COOH) groups were identified. Raman spectroscopy analysis provided additional insights, confirming these vibrational properties. These materials exhibited peak photon absorption (λmax) at 242 nm and an optical band gap of 3.7 eV. Frontier molecular orbital (FMO) analyses indicated significant electronic charge transfer on the materials' surfaces, demonstrating their excellent capacity for adsorbing MB. An optimal catalyst dosage of 50 mg was found to be most effective in accelerating the degradation of MB. Additionally, variations in the initial pH of the solution showed a direct correlation, with higher pH levels leading to enhanced degradation efficiency, reaching up to 97 % after 120 min. Quantum Theory of Atoms in Molecules (QTAIM) analyses revealed that MB is extensively adsorbed and degraded through a series of hydrogen bonding interactions. Moreover, experimental results indicate that both materials have a significant impact on bacterial destruction, suggesting their potential as novel antibacterial agents.

Synthesis, structural analysis, and molecular docking of a novel 1,3,4-thiadiazole derivative: An experimental and molecular modeling studies

This study reports on the synthesis and characterization of a new thiadiazole derivative, (E)-N-(5-(2-nitrostyryl) -4-acetyl -4,5-dihydro -1,3,4-thiadiazol -2-yl) -N-phenylacetamide (ETDZ). The crystal structure was determined by single-crystal X-ray diffraction. ETDZ belongs to the monoclinic I2/a space group. The contribution of intermolecular interactions was assessed by Hirshfeld surface analysis and fingerprint plots. FT-IR, UV–Vis, and NMR (1H and 13C) techniques were used for spectroscopic characterization. The 1H and 13C NMR spectra were recorded in CDCl3 solvent. Density functional theory, employing the B3LYP functional and 6–311G(d,p) basis set in chloroform solvent, was used to calculate the structural and spectroscopic parameters of the molecule in the ground state. The vibrational wavenumbers were calculated and compared with the experimental FT-IR spectrum using the scaled quantum mechanics method. Isotropic chemical shifts were calculated using the Gauge invariant atomic orbital method. The calculated NMR chemical shifts and absorption wavelengths were compared with the experimental values, indicating good results from the DFT and TD-DFT methods. To get more information about charge transfer within the molecule, electronic properties such as HOMO and LUMO energies were studied using the DFT approach. The molecular electrostatic potential, frontier molecular orbital analysis, energy band gap, density of state, global chemical reactivity descriptors, and some thermodynamic functions were also calculated. Reduced density gradient and atom-in-molecule analysis were performed to investigate inter- and intra-non-covalent interactions. Molecular docking was carried out with the Eg5 kinesin protein, confirming the biological assets of the ETDZ ligand as a mitochondria disease and cancer agent.

Remarkable enhancement of the nonlinear optical behavior towards asymmetric substituted D-π-A dithiophene-based compounds.

Nonlinear optics (NLO) is an interesting field that discloses the interaction between intense light and matter, leading to a deeper understanding of NLO phenomena. Organic chromophores are considered as promising materials for NLO due to their exceptional structural versatility, ease of processing, and rapid response to NLO effects. Functional materials based on thiophene have been indispensable in advancing organic optoelectronics. Specifically, dithiophene-based compounds display weaker aromaticity, reduced steric hindrance, and additional sulfur-sulfur interactions. Hence, by utilizing dithieno[2,3-d:2',3'-d']benzo[1,2-b:4,5-b']dithiophene (DTBDT) as the core structure, designing of a set of organic compounds with D1-π-D2-π-A-type framework, namely ZR1D1-ZR1D8, was carried out in this study. The analysis of frontier molecular orbitals (FMOs) revealed that compound ZR1D2 has the lowest band gap of 1.922eV among all the investigated chromophores. The correlation of global reactivity parameters (GRPs) with the band gap values indicates that ZR1D2 displays a hardness of 0.961eV and a softness of 0.520eV-1. Among the studied compounds, ZR1D2 demonstrated a broad absorption spectrum that extended across the visible region. The maximum absorption wavelengths were observed at 766.470nm for ZR1D2 and 749.783nm for ZR1D5. These DTBDT-based dyes exhibit a remarkable NLO response with exceptionally high first hyperpolarizability (βtot) values. Among them, compound ZR1D2 stands out with the highest average linear polarizability (⟨α⟩ = 3.0 × 10-22 esu), first hyperpolarizability (βtot = 4.1 × 10-27 esu), and second hyperpolarizability (γtot = 7.5 × 10-32 esu) values. In summary, this investigation offers valuable insights into the potential use of DTBDT-based organic chromophores, particularly ZR1D2, for advanced applications in NLO. These findings suggest promising opportunities for researchers to synthesize these molecules and utilize these compounds in hi-tech NLO-based applications. The density functional theory computations were performed at the M06/6-311G(d,p) functional to explore their structural effects on electronic and NLO findings. Various analyses like highest occupied molecular orbital-lowest unoccupied molecular orbital energy gaps, absorption maxima, density of states, open circuit voltage, binding energies of electrons and holes, and transition density matrix are employed to investigate photovoltaic efficiencies of the derivatives. Different software packages like Avogadro, Multiwfn, Origin, GaussSum, PyMOlyze, and Chemcraft were used to deduce conclusions from the output files.

Unveiling spectroscopic behaviour and molecular features (DFT studies) of Exemestane-maleic acid cocrystal as model multicomponent system

The present study aimed to investigate the Exemestane - maleic acid (Ex-Mal) cocrystal using Fourier-transform Raman (FT-Raman), Fourier-transform Infrared (FT-IR), Powder X-ray Diffraction (PXRD) and Differential Scanning Calorimeter (DSC) experimental techniques and quantum chemical calculations. Exemestane (Ex) is an irreversible aromatase inhibitor, clinically used for the treatment of postmenopausal women having primary or advanced breast cancer. Maleic acid (Mal), a dicarboxylic acid is found in many vegetables and fruits and is used as a food additive and sweetener. Solution crystallization of Ex and Mal was done in the generation of Ex-Mal cocrystal (1:1). PXRD and DSC analysis confirmed the successful generation of Ex-Mal Cocrystal. Intermolecular hydrogen bonding (O4-H12···O13 & C8-O3···H36) also suggested the formation of a multi-component system, Ex-Mal cocrystal (1:1), as the respective modes shifted in the vibrational (Raman & IR) spectra of cocrystal than the Ex. Further, the quantum theory of atoms in molecules (QTAIM) has been done to analyze the strength and nature of inter-/intra molecular hydrogen bonding. Natural bond orbital (NBO) analysis was performed to check the stabilization energy of the system. The frontier molecular orbital (FMO) analysis predicted that Ex-Mal cocrystal is more reactive and less stable than Ex. Molecular electrostatic potential (MEP) surface showed that electrophilic (C16-H36)/(O4-H12), and nucleophilic (C8=O3)/(C17=O13) reactive groups in Ex/Mal and Mal/Ex, respectively, neutralized after the formation of Ex-Mal cocrystal, confirming the presence of hydrogen bonding interactions (C16-H36∙∙∙O3=C8) and (C17=O13∙∙∙H12-O4). Molar Refractivity (MR) was calculated to check the drug-likeness behaviours of Ex-mal cocrystal. This study provided a comparison of experimental and theoretical results to understand the hydrogen bonding interactions and structural activity of the system.

Mechanism of bioactive 3,3′-diindolylmethane formation in flaxseed meal-xylose-tryptophan maillard reaction

3,3′-Diindolylmethane (DIM) has attracted extensive attention due to its bioactivity, and is applied to the fields of food, medicine and so on. In the study, DIM was isolated from the flaxseed meal-xylose-tryptophan Maillard reaction products. Its formation mechanism was investigated using the isotope labeling method. The reactive sites in DIM were analyzed by quantum chemistry calculation. The results showed that the Maillard reaction of tryptophan and xylose produced indole-3-formaldehyde, which further reacted to generate indole-3-methanol. Indole-3-methanol was unstable and eventually formed DIM. The molecular structure of DIM was determined and then the best configuration was obtained by frequency calculation. The molecular potential energy and frontier molecular orbital analysis showed that the main action site in DIM was near the indole ring. This study may provide a theoretical basis for in-depth studies on the relationship between the molecular structure and properties of DIM, broaden its applications in food, and offer a reference for the rational development of functional foods.

A rational design of metal doped C20 fullerene based sensor for the selective detection of ethyl butyrate as COVID-19 biomarker

The detection of ethyl butyrate as a COVID-19 biomarker in exhaled breath could be a novel, rapid, less expensive, painless and non-invasive technique compared to a costly, painful and time-consuming PCR test. The potential of alkaline earth metals doped C20 fullerenes (M@C20) was explored as sensing materials to detect ethyl butyrate selectively. The ethyl butyrate (EB) exhibited the physisorption on pristine C20 fullerene with adsorption energy of -4.16 kcal/mol, while chemisorption was observed with M@C20 fullerenes. The frontier molecular orbital analysis demonstrates enhanced stability of complexes, attributed to widened Eg gaps during EB adsorption onto M@C20 fullerenes. The notable shift in λmax values in the visible region suggests using M@C20 fullerenes as UV–visible-based naked-eye sensors. The infrared analysis showed a red shift in the carbonyl bond stretching frequency of ethyl butyrate upon adsorption onto M@C20 fullerenes. The red shift resulted from charge transfer from ethyl butyrate to M@C20. These findings establish the foundation for utilizing M@C20 fullerenes in IR-based handheld sensing devices. The minimum recovery time (6.8 s) demonstrates Ca@C20 fullerene as a promising, reusable sensor for detecting ethyl butyrate at human body temperature. Our results pave the way to design rapid, reusable sensors for detecting ethyl butyrate.

Theoretical evaluation of C24 nanocage functionalization with protons for enhanced sulfacetamide drug delivery: A DFT study with non-covalent interaction analyses

In the realm of drug design, achieving precise and effective drug delivery poses a significant challenge. In this computational study, we explore the capacity of pristine C24 nanocages and those modified with 1H+ and 2H+ ions to serve as carriers for the sulfacetamide (SA) drug, employing density functional theory (DFT) calculations. Geometry optimizations of the SA&C24, SA&H+C24, and SA&2H+C24 complexes were conducted at the cam-B3LYP/6–31+G (d, p) level of theory. The optimized structures of all complexes exhibit local minima on the potential energy surface, indicated by the absence of imaginary frequencies, which confirms their thermodynamic stability. The negative values of adsorption energy (Eads) denote an exothermic and favorable adsorption process, with H+ ion functionalization enhancing the drug's binding affinity to the nanocages. Further analysis of the structural properties of the complexes was conducted through natural bond orbital (NBO) charge distribution, dipole moment calculations, and frontier molecular orbital analysis. Additionally, Atoms in Molecules (AIM), reduced density gradient (RDG), and electron localization function (ELF) analyses were employed to elucidate the nature of intermolecular interactions governing the drug-nanocage binding. UV-visible and nonlinear optical (NLO) response calculations reveal the potential of both pristine and functionalized C24 nanocages as optical sensors for SA drug detection. Our findings suggest that these nanocages hold promise for the development of sensitive drug delivery vehicles and targeted therapeutic agents.

Crystallographic analysis, Hirshfeld surface investigation, and DFT calculations of 2-phenoxy-triazoloquinazoline molecule: Implications for drug design

This study presents a comprehensive structural and computational investigation of 2-phenoxy-1,2,4-triazolo[1,5-a]quinazoline (PTQ), a compound with promising pharmacological potential. Single-crystal X-ray diffraction (SCXRD) analysis revealed the molecular geometry and crystal packing, while density functional theory (DFT) calculations provided insights into electronic properties and reactivity. Hirshfeld surface analysis elucidated intermolecular interactions, highlighting hydrogen bonding, van der Waals forces, and π–π stacking as crucial factors in crystal stability. Fingerprint analysis quantified these interactions, revealing the dominance of hydrogen contacts and the significance of hydrogen bonds and C–H···π interactions. Void analysis identified potential areas for inclusion complex formation. Frontier molecular orbital analysis and molecular electrostatic potential (MEP) mapping identified potential electrophilic and nucleophilic sites, guiding future reactivity studies. Furthermore, in silico ADMET and molecular docking studies were performed to assess the drug-likeness and potential antihistamine activity of PTQ.

Exploration of supramolecular interactions, Hirshfeld surface, FMO, molecular electrostatic potential (MEP) analyses of pyrazole based Zn(II) complex

The supramolecular interactions of title compound [Zn(HL2)](ClO4)2(MeOH)2] (1) where, HL2=((Z)-N’-(5-methyl-1H-pyrazole-3-carbonyl)pyrazine-2-carbohydrazonamide) are explored in detail. With a detailed scrutiny of visualizing of title compound 1, the crystal packing is mainly directed by strong hydrogen bonding interactions observed N–H⋯N and N–H⋯O but, in addition, weak interactions such as C–H⋯π, π⋯π are also sighted to stabilize the crystal self-assembly. Electronic structure of the complex is determined using DFT calculations at B3LYP level with mixed basis set. Theoretically calculated structural parameters are in good match with the experimentally obtained parameters from XRD. TDDFT calculation is performed to simulate the UV–Vis absorption spectra of the complex. Molecular reactivity and stability of the complex has been assessed through frontier molecular orbital analysis and also through evaluation of molecular electrostatic potential (MEP). Hirshfeld surface analysis, which uses molecular surface contours and 2D fingerprint plots to visually analyze intermolecular interactions in crystal structures, has been used to examine molecular morphologies. The Hirshfeld surface and fingerprint plots are accompanied by crystal structure analysis allowed for the discovery of the important intermolecular interactions.

Hydration effects on molecular structure, vibrational, electronic properties, drug-likeness analysis, molecular docking, and molecular dynamics studies of (Z)-3-(2-oxo-2-phenylethylidene)indolin-2-one

This study examines how solvation models, including COSMO, CPCM, PCM, and SMD, affect the conformations, molecular structure, vibrational behaviors, and electronic properties of the (Z)-3-(2-oxo-2-phenylethylidene)indolin-2-one (Z3-2O2PEI) molecule within the framework of the B3LYP/cc-pVTZ model chemistry, along with its potential effectiveness as a drug for treating COVID-19. The most stable molecular conformation of the studied coùpound was identified in the presence of the COSMO solvent. The theoretical vibrational frequencies matched the experimentally observed FT-IR and Raman data. Solvent influences on the UV–vis spectra of Z3-2O2PEI revealed electronic transitions from n to π* and π to π* orbitals, along with evidence of intermolecular charge transfer (ICT) supported by analyses of Frontier Molecular Orbitals (FMO) and Natural Bond Orbitals (NBO). The examinations of Mulliken atomic charge distributions and molecular electrostatic potential surfaces reveal the electrophilic and nucleophilic sites of the molecule under study. Non-covalent Interaction (NCI) analysis confirmed the presence of steric effects and Van der Waals interactions within the compound. According to molecular docking studies, the Z3-2O2PEI molecule exhibits significant binding affinity for PLpro, a protein targeted in COVID-19 treatment. This finding is supported by subsequent molecular dynamics analysis, validating the docking results.

Pyrimidine-based sulfonamides and acetamides as potent antimicrobial Agents: Synthesis, Computational Studies, and biological assessment

A series of novel sulfonamide and acetamide derivatives of pyrimidine were synthesized and their antimicrobial activities were assessed. Based on the Microbroth dilution method, the minimum inhibitory concentration (MIC) of the synthesized compounds demonstrated moderate to good levels of antifungal and antibacterial activity. Structure-activity relationship analysis suggested that the presence of electron-withdrawing groups, such as halogens, nitrile, and nitro groups, on the pyrimidine ring contributed to the enhanced antimicrobial potency, while electron-donating substituents led to a decrease in activity. Computational studies, including density functional theory (DFT), frontier molecular orbitals (FMO), and molecular electrostatic potential (MEP) analysis, provided insights into the electronic properties and charge distribution of the compounds. Drug-likeness evaluation using ADME/Tox analysis indicated that the synthesized compounds possess favorable physicochemical properties and could be potential drug candidates. Molecular docking against the Mycobacterium TB protein tyrosine phosphatase B (MtbPtpB) revealed that the synthesized compounds exhibited strong binding affinities (−46 kcal/mol to − 61 kcal/mol) and formed stable protein–ligand complexes through hydrogen bonding and π-π stacking interactions with key residues in the active site. The observed interactions from the docking simulations were consistent with the predicted interaction sites identified in the FMO and MEP analyses. These findings suggest that the synthesized pyrimidine derivatives could serve as promising antimicrobial agents and warrant further investigation for drug development.

Computational insights into the underlying mechanism of zinc ion-specificity of the fluorescent probe, BDA-1

Ion specificity is crucial for developing fluorescence probes. Using a recently reported optical sensor (BDA-1) of Zn2+ as a representative, we carried out extensive quantum chemical calculations on its photophysical properties using density function theory. According to the calculated optimized geometries, excitation energies and transition oscillator strengths, the weak fluorescence of BDA-1 observed in experiments is attributed to the suppression of fluorescence emission by efficient internal conversion, rather than the previously proposed photoinduced electron transfer (PET) mechanism. With the addition of Zn2+ or Cd2+ ions, the tetradentate chelates [M:BDA-1-H+]+ (M=Zn, Cd) are produced. According to frontier molecular orbital and interfragment charge transfer analyses of these complexes, PET is preferentially confirmed to occur upon photo-excitation. Notably, as one coordination bond in the excited [Cd:BDA-1-H+]+ complex is significantly weakened in comparison to that of [Zn:BDA-1-H+]+, their molecular orbital compositions in the S1 state are completely different. As a result, absorption and radiation transitions of [Zn:BDA-1-H+]+ both have considerable oscillator strength, while fluorescence radiation from the excited [Cd:BDA-1-H+]+ is doubly suppressed. This difference causes that the fluorescence intensity of BDA-1 is sensitive to the addition of metal ions, and exhibits the zinc ion-specificity.

Microwave-assisted click synthesis, characterisation, and In silico studies of novel 2H-chromene-1,2,3-triazolyl glycoconjugates as potent anticancer and antibacterial agents

A series of novel 2H-chromene-1,2,3-triazolyl glycoconjugates 10a-w were synthesized, well characterized and evaluated for their in vitro antimicrobial and anticancer activities. Among the tested compounds, 10a, 10b, 10u, 10v, and 10w exhibited the most excellent potency against both gram-positive (S. aureus) and gram-negative (E. coli) bacterial strains relative to the standard drug, Gentamicin. The anticancer results showed that in MCF-7 cell line all the tested compounds exhibited better activity as compared to other two cancer cell lines (MDA-MB-231 and A549). Compounds 10t, 10u, 10v, and 10w showed significant cytotoxicity against MCF-7 cell line. The molecular docking studies suggested that all the four potent compounds exhibited a greater affinity for the selected receptors. Experimentally and computationally observed structure-activity relationships indicates, -OCH3 group at R2 position in benzopyran ring with tosyl-protected sugar containing compound 10b and benzyl-protected sugar containing compound 10t enhanced the antibacterial and anticancer activity respectively. Frontier molecular orbital analysis of compounds using the global reactivity parameters indicated that benzyl-protected sugar and acetyl-protected sugar containing compounds are stable and exhibits low reactivity. Moreover, molecular electrostatic potential analysis plots clearly showed that the compounds have strong electrophonic reaction potential. Moreover, the assessment of ADMET predictions revealed favourable pharmacokinetic properties of the investigated compounds. Collectively, it was observed that compounds 10u, 10v, and 10w could be considered as promising dual anticancer antibiotic inhibitors.

Indazole-5-amine (AIA) as competing corrosion coating to Benzotriazole (BTAH) at the interface of Cu: A DFT and BOMD case study

This study compares three organic compounds—benzotriazole (BTAH), imidazole (IM), and indazole-5-amine (AIA)—as corrosion inhibitors for copper substrates. Using Density Functional Theory (DFT) and Born-Oppenheimer Molecular Dynamics (BOMD) calculations, it identifies AIA as a promising and cost-effective alternative to the toxic BTAH. The adsorption strength on Cu(100) surfaces is ranked AIA>BTAH>IM for both neutral and deprotonated forms. These findings are supported by electronic parameter studies, including Bader charge analysis, density of states (DOS), charge density differences (CDD), and frontier molecular orbital analysis. AIA shows the best adsorption in a parallel orientation at the top site. Packing studies reveal that hydrogen bonding stabilizes the interaction energies within self-assembled AIA aggregates. Organometallic complexation studies reveal that deprotonated BTAH exhibits higher interaction energy with a single Cu atom compared to AIA when bonded through the carbon end, consistent with the findings from BOMD studies. However, on periodic Cu surfaces, AIA outperforms BTAH molecules as seen from adsorption energies. This investigation highlights AIA’s potential as a superior and more economical corrosion inhibitor for copper.

Interdisciplinary insights into (1′R,3S,3′R)-1'-(4-chlorobenzoyl)-5′,6′,7′,7a′-tetrahydro-1′H dispiro[indoline-3,2′-pyrrolizine-3′,3″-indoline]-2,2″-dione: Structural, electronic, and molecular dynamics perspectives

In the field of heterocyclic compounds, the spiro-pyrrolidine and oxindole ring systems are highly esteemed due to their distinctive structural scaffold that is present in numerous pharmacologically significant alkaloids. Interdisciplinary research has been increasingly important in recent years for deciphering the intricate characteristics and behaviors of novel organic compounds. The current work uses quantum chemical computational techniques to study the structural stability and nonlinear optical (NLO) activity of (1′R,3S,3′R)-1'-(4-chlorobenzoyl)-5′,6′,7′,7a′-tetrahydro-1′H dispiro[indoline-3,2′-pyrrolizine-3′,3″-indoline]-2,2″-dione (DSOIP-Cl). The study combines molecular biology, computational chemistry, and theoretical chemistry knowledge to create a comprehensive picture of this fascinating organic compound. This study employed the density functional theory (DFT) B3LYP method to compute the electronic properties and molecular geometry. The basis set for the computations was 6–311++G(d,p). The IEFPCM solvation method is used to investigate the behavior of the head compound in different solvents. Understanding the interaction between organic compounds and the solvent phase is crucial because the majority of interactions in biological systems occur in solution. UV–Vis spectral analysis of the molecule in different solvents is performed using the TD-DFT method. The compound exhibits more excellent absorption in polar solvents such as water, while its absorption is lower in the gaseous phase. Assessing NLO properties revealed optoelectronics applications. DSOIP-Cl has 5.25 times the first-order hyperpolarizability of urea. Different solvents have higher dipole moments and first-order hyperpolarizability than gases. To identify the inter- and intramolecular charge transfer interactions, intermolecular hydrogen bonding, and hyperconjugative interactions that stabilize the structure, natural bond orbital (NBO) analysis is performed. A stabilization energy of 9.99 kcal/mol is obtained for π(C32–C33) → σ*(C33–C34) due to strong intramolecular hyperconjugative interactions. Frontier molecular orbital (FMO) analysis helps determine the global reactivity parameters and the charge transfer interaction. The van der Waals interaction and steric effect within the molecule are identified using RDG analysis. The pharmacokinetic properties, adherence to drug-likeness criteria, and easily controllable synthesis process were evaluated through ADME analysis, establishing it as an up-and-coming candidate for subsequent drug development. Ultimately, to determine the biological activity and the ability of the title compound to inhibit aldose reductase, a series of computational techniques are employed, including molecular docking study, molecular dynamic (MD) simulation, and MM-PBSA binding energy calculations. −7.86 kcal/mol was reported as the docking score. Hydrophobic interactions play an essential role in the efficiency of protein-ligand binding. The remarkable energetic contribution of DSOIP-Cl to the MM-PBSA binding dynamics highlights its unique association with the AR protein, with a binding energy of −79.81 kJ/mol.

Potential antioxidant and antiradical agents from Allium ascalonicum: Superoxide dismutase and density functional theory in silico studies.

Antioxidants are compounds that can inhibit excessive free radical reactions in the body. Excessive free radicals can cause system imbalances in the body which can trigger oxidative stress and cause serious illness. The limitations of antioxidants in the body can be overcome by consuming safe natural additional antioxidants that can be obtained from natural products. Isolating compounds of Allium ascalonicum leaves as antioxidant and antiradical agents in inhibiting excessive free radicals by in vitro and in silico. The extracted compounds were purified by column chromatography. The compounds obtained were then characterized using ultraviolet, infrared, NMR, and mass spectrometry. Determination of antioxidant activity was carried out by in vitro using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the non-enzymatic superoxide dismutase (SOD) methods. The in silico study used the density functional theory (DFT) calculation method with global descriptive parameters (GDP), donor acceptor map (DAM), and frontier molecular orbitals (FMO) analysis. Three compounds have been isolated, of which compound 1 is a new compound. In the DPPH method, compound 1 has more strong antioxidant activity than others, as well as in the non-enzymatic SOD method. Whereas, in the DFT calculation shows that compound 1 has the best reactivity and stability between other compounds and was categorized as the best antiradical. Compound 1 has the highest antioxidant activity compared to the other compounds by in vitro both the DPPH and non-enzymatic SOD methods. In silico, compound 1 has the potential as the best antiradical.

Synthesis, Characterization, and Cytotoxicity of a Ga(III) Complex with Warfarin

The gallium(III) complex of warfarin was synthesized, and its structure was determined by means of theoretical, analytical, and spectral analyses. Significant differences in the IR and Raman spectra of the complex were observed as compared to the spectra of the ligand and confirmed the suggested metal-ligand binding mode. The theoretical study of the Ga(III) complex of warfarin has been done to elucidate the structure-activity relation, inter- and intra-molecular interactions, and frontier molecular orbital energy analysis based on DFT computations. A molecular docking study has been performed to predict the biological activity of the molecule. In this paper, we report preliminary results about the cytotoxicity of the investigated compounds. The cytotoxic effects of the ligand and its Ga(III) complex were determined using the MTT method on different tumor cell lines. The screening performed revealed that the tested compounds exerted cytotoxic activity on the evaluated cell lines.

In-situ formation of hydrophobic deep eutectic solvents to separate lactic acid: Lactam as hydrogen bond acceptor and lactic acid as hydrogen bond donor

Lactic acid (LA) is a typical high added-value chemical and platform molecule derived from renewable biomass. To realize high efficiency and green separation of LA is of both scientific and practical significance. In this work, we proposed a novel mechanism of in-situ formation of hydrophobic deep eutectic solvents (HDES) to couple the separation of LA and synthesis of HDES. Due to the high solubility of LA as hydrogen bond donor in water, three hydrophobic lactams (N-Octyl-2-pyrrolidone (NOP), N-Dodecyl-2-pyrrolidone (NDP) and 2-Octyl-4-isothiazolin-3-one (OIT)) were optioned as hydrogen bond acceptors. The effect of lactam molecular structure on separation efficiency was discussed and compared in detail. The compositions of HDES forming in-situ were found to be 1.50 for NOP and NDP to LA while 1.20 for OIT to LA using experiments of slope method and continuous variations method. The key evidence of formation of HDES was confirmed by FT-IR, frontier molecular orbital analysis and interaction region indicator analysis. The multistage counter-current extraction experiment results showed the in-situ formation of HDESs can transfer 99% of LA from fermentation broth to the HDES, and LA was separated completely from the impurities. This work provided a new perspective on lactic acid separation and its potential industrial applications.

Synthesis and structural investigation of salts of 2-amino-3-methylpyridine with carboxylic acid derivatives: an experimental and theoretical study.

The salts bis(2-amino-3-methylpyridinium) fumarate dihydrate, 2C6H9N2+·C4H2O22-·2H2O (I), and 2-amino-3-methylpyridinium 5-chlorosalicylate, C6H9N2+·C7H4ClO3- (II), were synthesized from 2-amino-3-methylpyridine with fumaric acid and 5-chlorosalicylic acid, respectively. The crystal structures of these salts were characterized by single-crystal X-ray diffraction, revealing protonation in I and II by the transfer of a H atom from the acid to the pyridine base. In the crystals of both I and II, N-H...O interactions form an R22(8) ring motif. Hirshfeld surface analysis distinguishes the interactions present in the crystal structures of I and II, and the two-dimensional (2D) fingerprint plot analysis shows the percentage contribution of each type of interaction in the crystal packing. The volumes of the crystal voids of I (39.65 Å3) and II (118.10 Å3) have been calculated and reveal that the crystal of I is more mechanically stable than II. Frontier molecular orbital (FMO) analysis predicts that the band gap energy of II (2.6577 eV) is lower compared to I (4.0035 eV). The Quantum Theory of Atoms In Molecules (QTAIM) analysis shows that the pyridinium-carboxylate N-H...O interaction present in I is stronger than the other interactions, whereas in II, the hydroxy-carboxylate O-H...O interaction is stronger than the pyridinium-carboxylate N-H...O interaction; the bond dissociation energies also confirm these results. The positive Laplacian [∇2ρ(r) > 0] of these interactions shows that the interactions are of the closed shell type. An in-silico ADME (Absorption, Distribution, Metabolism and Excretion) study predicts that both salts will exhibit good pharmacokinetic properties and druglikeness.

Novel series of hydrazones carrying pyrazole and triazole moiety: Synthesis, structural elucidation, quantum computational studies and antiviral activity against SARS-Cov-2

The novel series of hydrazones carrying both pyrazole and triazole moiety were synthesized and characterized using single crystal X-ray diffraction studies. It is found that the compound crystallizes in the triclinic system in the space group P1̅. Hirshfeld analysis was carried out to visualize the noncovalent intermolecular interactions which are responsible for molecular packing in the crystal. Further, density functional theory (DFT) calculations were used to calculate optimized molecular structure, stability, and a few of the quantum chemical parameters. Derived results are in good agreement with the experimentally obtained results. Analysis of frontier molecular orbitals (HOMO and LUMO) and their energy gap of the optimized structure revealed that the compound is stable in the gaseous state. Molecular electron densities, and electrostatic potential maps provide the reactive site and charge distribution of triazole group. Quantum theory of atoms in molecules (QTAIM) and reduced density gradient (RDG) analysis were carried out to explore the weak interactions present in the molecule. In addition, the synthesized compound was investigated as an inhibitor for SARS CoV-2 protease using in-silico molecular docking analysis to understand the mode of binding. The docking results showed the good binding score with Mpro protease 6LU7. Further, molecular dynamics (MD) were carried out for the best hit docked complexes.