Density Gradient Analysis Research Articles

Leveraging almost hydrophobic PVDF membrane and in-situ ozonation in O3/UF/BAC system for superior anti-fouling and rejection performance in drinking water treatment.

The almost hydrophobic PVDF membrane (PVDF matrix) commonly exhibited excellent performance in pollutant rejection but with poor anti-fouling performance. This study intended to develop the rejection performance and enhance anti-fouling of the PVDF membrane in an O3/UF/BAC system for high quality water production through leveraging the advantages of in-situ ozonation and the nature of the PVDF membrane. Reduced density gradient (RDG) analysis demonstrated that the PVDF membrane exhibited excellent ozone resistance by reducing hydrogen bonds and electrostatic interactions between the membrane surface and ozone. Consequently, the physicochemical properties of the PVDF membrane remained unchanged in the laboratory continuous flow experiment with in-situ ozonation at 2.86 mg/L. The almost hydrophobicity of the PVDF membrane not only resisted fouling but also facilitated the reaction between ozone and foulants of higher concentrations locally at membrane surface, leading to dynamic changes in membrane fouling, with TMP/TMP0 initially increasing, then decreasing and stable. Therefore, the Rtotal, Rcake and Rgel of the PVDF membrane decreased by 47.40 %, 46.79 % and 50.99 % as compared to the UF/BAC system, respectively, in the O3/UF/BAC system. In-situ ozonation transformed macromolecular substances into micromolecules, particularly organic matter with lignin/carboxylic-rich alicyclic molecules and aromatic structures. The majority of these micromolecules were either rejected by the deposited foulants layer through Van der Waals interaction and utilized as a carbon source by membrane surface microorganisms (eg., Curvibacter and Methyloversatilis), or further degraded by microorganism in the BAC unit. This resulted in a 19.34 % and 40.58 % reduction in CODMn concentrations in the UF and BAC effluents, respectively. The system's anti-fouling and water purification performance observed in laboratory experiments was confirmed in a pilot test, providing new insights into the use of in-situ ozonation and organic membranes.

Non-covalent interactions in conjugated polymer blends: Insights into the stability of PVC/PM6 and CPE/PM6 systems.

This study investigates the role of non-covalent interactions (NCIs) in stabilizing blends of the conjugated polymer PM6 with additives polyvinyl chloride (PVC) and chlorinated polyethylene (CPE). Using the NCI index, reduced density gradient analysis, and energy decomposition analysis (EDA), we quantify the contributions of van der Waals forces, hydrogen bonding, and steric repulsions in these systems. Our results reveal that PVC/PM6 blends exhibit stronger NCI, particularly C-H⋯π and C-Cl⋯π interactions, compared to CPE/PM6 blends. EDA further shows that dispersion forces and electrostatic interactions are the primary stabilizing factors in the PVC blend, with hydrogen bonding also playing a critical role. These findings highlight the importance of chlorine content in enhancing NCI and promoting the stability of polymer blends. The insights from this work provide valuable guidance for designing more stable polymer-additive systems in organic electronics and other material applications.

Synthesis, Urease Inhibitory Activity, Molecular Docking, Dynamics, MMGBSA and DFT Studies of Hydrazone-Schiff Bases Bearing Benzimidazole Scaffold.

In this study, eleven hydrazone-Schiff bases bearing benzimidazole moiety were synthesized successfully via three step reactions and structures of these products were deduced by HR-ESI-MS, 1H-, and 13C-NMR spectroscopic techniques. Lastly, these derivatives were tested for their in vitro urease inhibitory potential. Six compounds among the series attributed excellent inhibition with IC50 values of 7.20±0.59 to 19.61±1.10 μM better than the reference drug thiourea (IC50=22.12±1.20 μM). Similarly, three derivatives showed significant while two compounds showed less inhibitory effects against the urease enzyme. The molecular docking analysis was carried out to reveal the binding modes and types of interaction taking place between protein (urease) and synthesized compounds. The Density Functional Theory (DFT) calculations were performed at B3LYP/6-311++G(d,p) to check the structure stability. For the account of intramolecular interaction, the DFT-D3 and Reduced Density Gradient (RDG) analysis were performed. Furthermore, the chemical nature of all compounds was explored by TD-DFT method using CAM-B3LYP functional with 6-311++G(d,p) basis set. The dynamic simulation as well as MMGBSA studies validated the binding affinity and stability of the ligand receptor complex, displaying main interactions contributing in the biological activity of the product derivatives.

Silver- and gold-catalyzed azide−alkyne cycloaddition by functionalized NHC-based polynuclear catalysts: Computational investigation and mechanistic insights

This study evaluated the catalytic efficiency of Au(I), Ag(I), and Cu(I) complexes in the azide‒alkyne cycloaddition (AAC) reaction through density functional theory (DFT) calculations. Cu(I) complexes exhibit superior catalytic performance, with lower energy barriers (8.8 kcal/mol) and a favorable Gibbs free energy of -0.9 kcal/mol in the key cycloaddition step, significantly outperforming Ag and Au complexes. Structural analysis revealed that shorter M−C bond lengths in the Cu complex contributed to increased stability. Additionally, the copper complex has a more negative Gibbs free energy for the formed metallacycle, indicating a thermodynamically favorable reaction pathway. Noncovalent interaction (NCI) and reduced density gradient (RDG) analyses of the Cu, Ag, and Au systems highlighted distinct interaction patterns influencing the reactivity. Furthermore, electron localization function (ELF) and localized orbital locator (LOL) analyses revealed bonding characteristics in those complexes. This study offers valuable insights into the mechanistic differences among Au(I), Ag(I), and Cu(I) complexes, paving the way for future research on enhancing the catalytic activity of copper, silver and gold complexes through ligand modification.

Structure elucidation and computational studies of the thiazole derivative against SARS-CoV-2 virus: Insights from XRD, DFT, molecular docking, and molecular dynamics simulation

The present work is focused on the crystal structure, Hirshfeld surface, Density Functional Theory (DFT) studies of thiazole derivative N-benzyl-4-(4-bromophenyl)thaiazole-2-carboxamide (TT4). The crystal structure has been determined using single crystal X-ray diffraction analysis, which shows that the compound crystallizes in the monoclinic crystal system with space group P21/c. C-H⋯O type of hydrogen bond interaction is responsible for the crystal packing in crystal The molecular geometry optimization was performed by DFT calculations. The 2D scattered plot was generated by Reduced Density Gradient (RDG) analysis, which divulge the weak and noncovalent interactions in the compound TT4. In silico studies were carried out to delve into the binding pattern of the TT4 compound against SARS-CoV-2 proteins using molecular docking and molecular dynamics simulation. Finally, the binding free energy and the contributed energies were derived using MM-GBSA approach. The 7K40-ligand complex showed the highest binding free energy, and among all other interactions, the contributions of the covalent binding and van der Waals energy were found to be significant.

Elucidating the E‐Cadherin⋯ADTC5 Interactions: A Theoretical Examination of Amino Acid Active Site Binding on the Electronic Level via Density Functional Theory

AbstractThe presence of E‐cadherin⋯E‐cadherin interactions in the intercellular space (paracellular pathway) poses a notable limitation in drug delivery across the blood‐brain barrier (BBB). ADTC5 peptide has shown promising results in improving drug delivery across the BBB by modulating E‐cadherin⋯E‐cadherin interactions. However, the study of E‐cadherin⋯ADTC5 amino acid interactions using quantum mechanics approach has not been observed clearly. Herein, we observed the interaction between E‐cadherin⋯ADTC5 amino acids using density functional theory (DFT). Natural bond orbital (NBO), quantum theory of atoms in molecules (QTAIM), and reduced density gradient (RDG) analysis are performed to study the non‐covalent interaction in detail. The Arg55⋯Asp2 shows the strongest interaction between E‐cadherin⋯ADTC5 modulation, indicated by the highest stabilization energy (E(2)), and hydrogen bonding energy (EHB) about 22.04 and −6.90 kcal/mol, respectively. This interaction is dominated by hydrogen bonding. Such advancements could lead to significant improvements in therapeutic strategies for neurodegenerative diseases, where effective drug delivery across the BBB remains a major challenge.

Vibrational Spectra and Computational Study of Amyl Acetate: MEP, AIM, RDG, NCI, ELF and LOL Analysis

This work is focused on biologically active neat amyl acetate and its solutions in ethanol/heptane. According to the experimental results, when the concentration of amyl acetate in the amyl acetate-ethanol solution decreases, the additional band appears on the low-frequency side. The primary reason for the formation of such additional band is the intermolecular hydrogen bonding between amyl acetate and ethanol. In the amyl acetate-heptane solution, as the concentration of amyl acetate in the solution decreases, the band corresponding to the C=O stretching vibrations shifted to a higher frequency. This is explained by the fact that heptane breaks intermolecular interactions in solution, resulting in a simpler spectral band corresponding to the C=O stretching vibrations. Calculations are also used to study interactions in amyl acetateethanol complexes and their spectral manifestations. When the complex formation energies are calculated, this energy increases with the number of molecules, but the average hydrogen bond energy per one bond remains unchanged. The density functional theory (DFT) method is used to analyze molecular structural parameters: Mulliken atomic charge distribution; thermodynamic parameters; molecular electrostatic potential (MEP) surface; atoms in molecules (AIM) analysis; quantum chemical parameters such as reduced density gradient (RDG) and noncovalent interaction (NCI) analysis; electron localization functions (ELF) analysis; and localized orbital locator (LOL) analysis.

Synthesis, Crystal Structure, Intermolecular Interactions, HOMO-LUMO, MEP, NLO Properties, and DFT/TD-DFT Investigation of (Z)-5-(4-Nitrobenzylidene)-3-N(3-Chlorophenyl)-2-Thioxothiazolidin-4-One

A novel heterocyclic compound named (Z)-5-(4-nitrobenzylidene)-3-N(3-chlorophenyl)-2-thioxothiazolidin-4-one (NCTh) was synthesized and analyzed using various techniques, including single crystal X-ray diffraction, FT-IR, UV-Vis, NMR spectroscopy, and mass spectral data methods. NCTh was observed to crystallize in the triclinic crystal system P-1 space group. To validate the experimental findings, density functional theory (DFT) calculations were performed using the B3LYP functional with the 6-311 G(d,p) basis set. The results indicated good agreement in geometrical parameters between the experimental and theoretical outcomes. The study also calculated HOMO-LUMO energies, molecular electrostatic potential (MEP), and global chemical reactivity descriptors to evaluate the compound’s reactivity. Additionally, the study conducted reduced density gradient and Hirshfeld surface analyses to reveal attractive, repulsive, and van der Waals strong and weak interactions. The calculation of thermodynamic parameters was also included. The study focused on investigating the nonlinear optical (NLO) properties of NCTh, which were characterized through key parameters such as the electric dipole moment (µ), polarizability (α), first-order hyperpolarizability (β), and second-order hyperpolarizability (γ). These properties provide insights into the material’s potential applications in optical and photonic technologies. Additionally, a molecular docking study was performed to further explore the structure-activity relationship, particularly in a biological context. The docking results revealed a strong ligand-protein interaction, with a binding energy of −10.3 kcal/mol, indicating significant affinity. Moreover, the inhibition constant (Ki) was calculated to be 0.0281 μM, suggesting a highly potent interaction, which could be relevant for drug design or biochemical applications.

Lithospermic acid inhibits dengue virus infection through binding with envelope proteins

The dengue virus has emerged as a global pandemic, highlighting the urgent need for the immediate development of antiviral therapeutics. Lithospermum erythrorhizon, a medicinal plant commonly used in China for various ailments including viral infections, inflammation, rheumatism, and cancer, showed promising antiviral properties in our research. Specifically, both the ethanol extract of Lithospermum erythrorhizon and its active component, lithospermic acid, demonstrated significant inhibitory effects on Dengue virus (DENV) replication in Vero cells, with EC50 values of 6.50 μg/mL(95 % CI: 2.25 to 18.98)and 15.00 μM(95 % CI: 12.13 to 18.07), respectively. Notably, lithospermic acid exhibited potent antiviral activity across multiple cell lines against DENV, impeding virus replication and specifically impeding the expression of viral E and NS3 proteins during the early stages of DENV infection. Experimental assays involving RNase digestion and sucrose density gradient analysis confirmed that lithospermic acid did not directly inactivate DENV but rather interfered with viral processes. Furthermore, the compound was found to bind to the E protein of DENV, effectively inhibiting viral infection and mitigating the cytopathic effects induced by DENV. Collectively, these findings underscore the potential of lithospermic acid as a promising candidate for the development of therapeutic strategies targeting DENV infection.

Investigation on induced smectic phases in double hydrogen bond liquid crystal complexes derived from aromatic carboxylic acids: Experimental and quantum chemical approaches

In the present study, double Hydrogen bond liquid crystal (HBLC) complexes in different mole ratio (1:1 and 1:2) have been isolated from symmetrical aromatic dicarboxylic acid of non-mesogenic compound 1,3-Phenylenediacetic acid (1,3-PDA) and mesogenic compound 4-n-dodecyloxybenzoic acid (12 OBA). Fourier transform infrared Spectroscopy (FTIR) explores the presence of functional groups in the title complexes. Formation of H-bond between 1,3-PDA and 12 OBA is experimentally confirmed by observing the FTIR peak at 3639 cm−1 (1:1 ratio). Induced mesophases and its textures along with transition temperatures are analyzed using polarizing optical microscope (POM) and differential scanning calorimetry (DSC). The layered structures (smectic phases) and their molecular mechanism has been analyzed using density functional theory (DFT). Further, the establishment of H-bond in the title complex has been investigated with the aid of optimized geomentry, molecular electrostatic potential (MEP) and reduced density gradient (RDG) analysis. The band gap energy of title complex (1:1) is calculated by UV–Vis spectrometer and the same has been justified by HOMO-LUMO studies. Maximum absorption in the UV region and moderate bandgap energy (Eg = 4.22 eV) of the title complex clearly indicates its potential application in NLO, optoelectronics and laser tuning devices. In addition to that, LC parameters and its effect on mesophase are reported using experimental and computational methods.

Empirical, computational studies and non-covalent interactions analysis of a novel salt with cadmium transition metal precursor

In this research paper, (C3H5N2)6[CdCl4][CdCl6] was successfully synthesized using a slow evaporation process. The structure was confirmed through single-crystal X-ray crystallography, FT-IR, and thermal analysis. The material was found to crystallize in the tetragonal system (space group I41/a) and the following parameters a = b = 12.0872 (8) Å; c = 24.6985 (16) Å, the crystal packing shows parallel layers of cations and stacks of discrete anions positioned at y = 1/4 and 3/4. The junction between the monoprotonated imidazolium cations and the anions, along with the crystal structure stability, relies on Cl···H−N, and Cl···H−C hydrogen bonds. Computational investigations, conducted using the B3LYP method with 6–311++G(d,p) and LANL2DZ mixed basis set, demonstrated close alignment between the computed and the experimental data, providing insights into the material's geometrical and vibrational properties. The non-covalent interactions were studied through Atoms-In-Molecule (AIM) and Reduced Density Gradient (RDG) analysis and quantitatively using the Hirshfeld surfaces associated with 2D fingerprint plots. Furthermore, thermal stability was assessed through Thermogravimetric and Differential Scanning Calorimetry (TG–DSC) analysis.

Morphology studies, optic proprieties, hirschfeld electrostatic potential mapping, docking molecular anti-inflammatory, and dynamic molecular approaches of hybrid phosphate

The above current study intends to identify new prospects for developing viable epilepsy treatments. To attain this purpose, the created P-carboxylammonium di-hydrogen monohydrate called (I). The research reveals the existence of both intermolecular (O–H⋯O) as well as N–H⋯O intramolecular hydrogen bonding in crystal packing patterns. As the fingerprint plots illustrate the different sorts of interactions and the hybrid system's relative abundance of each, However, the molecular docking results clearly demonstrate five typical hydrogen bonds, with the best binding posture of −4.757 kcal/mol for Lys244, Val272, Arg241, and Glu273 proteins when docked with (I) ligand. As a result, we may deduce that if the (I) ligand is a pharmaceutical used to treat epilepsy, it will probably be more potent than the conventional medication. As a result, (I) was simulated using molecular dynamics (MD) and is proposed as a viable therapeutic target for antiepileptic therapy. Reduced Density Gradient (RDG) analysis, highlighted the presence of significant non-covalent interactions (NCI) that contribute to the stability and structural integrity of the compound, emphasizing the importance of these interactions in the context of its potential applications, particularly in drug design and molecular interactions. Finally, the ELF and LOL analyses collectively enhance the understanding of the electronic structure of compound I, revealing critical information about electron distribution, localization, and the nature of interactions within the molecular framework. These insights are essential for predicting the compound's reactivity and potential applications in fields such as pharmaceuticals and materials science.

Experimental and theoretical studies of alkyl 2-(2,4,6,8-tetraaryl-3,7-diazabicyclo[3.3.1]nonan-9-ylidene)hydrazine carboxylates: Synthesis, spectroscopic, crystal structure, Hirshfeld surface, and antimicrobial studies

The nine alkyl 2-(2,4,6,8-Tetraaryl-3,7-diazabicyclo[3.3.1]nonan-9-ylidene)hydrazine carboxylates having bicyclic bispidine core were synthesized and characterized using FT-IR, NMR, and mass spectra. Further confirmation of the structure and positioning of the groups was obtained using single crystal XRD investigation. The analysis revealed that one piperidine ring adopts a chair and another a boat form. The aryl groups in the chair conformation are positioned equatorially, whereas those in the boat conformation are orientated axially. The carbazate group (C=N-NH-COOR) aligned the center of the two piperidine rings, with a small deviation towards the boat conformation piperidine ring. The dihedral angle between the chair and boat conformations of the piperidine ring (2f) is 48.51 Å and 45.12 Å, respectively. Hirshfeld and 2D fingerprint analysis show considerable H···H bonding interactions in the crystal. The intermolecular interaction and mechanical stability of crystals were investigated using interaction energy and crystal void analysis. Reduced density gradient and localized orbital locator analyses were used to investigate intramolecular interactions and electron delocalization. The molecule's higher and lower electron densities were investigated utilizing frontier molecular orbital analysis and Molecular Electrostatic Potential. The antimicrobial activity of the compounds was investigated using four bacterial and two fungus strains.

Harnessing high potential benzothiazole chalcones against dengue virus NS5 protein: A multi-faceted theoretical study through molecular docking, ADME, and DFT

Chalcones bearing tetralone, indanone and benzothiazole cores were synthesized successfully using a general Claisen-Schmidt condensation protocol. The prepared compounds were purified and structurally analyzed by 1H, 13C NMR, and FT-IR techniques. A multi-faceted theoretical approach, combining Density Functional Theory (DFT), molecular docking, and ADME predictions, was employed to evaluate their therapeutic potential. DFT calculations at the B3LYP/def2-TZVP level revealed key electronic properties, with TD3 compound demonstrating the highest chemical reactivity. Molecular Electrostatic Potential (MEP) and Reduced Density Gradient (RDG) analyses provided insights into the compounds' non-covalent interactions and charge distributions. Molecular docking studies against the NS5 protein (PDB: 6KR2) showed superior binding affinities for all three compounds compared to the control ligand SAH, with TD3 exhibiting the lowest binding energy (−8.41 kcal/mol) and theoretical inhibition constant (689.31 nM). ADME predictions indicated favorable drug-like properties with concerns regarding aqueous solubility and potential P-glycoprotein interactions. Toxicity evaluations highlighted challenges, particularly in hepatotoxicity and carcinogenicity. The study identified TD3 as a promising lead compound for Dengue Virus NS5 inhibition, while also emphasizing the need for targeted modifications to address toxicity concerns. This research not only contributes to anti-dengue drug discovery efforts but also provides a robust methodological framework for the theoretical evaluation of similar small compounds in future investigations.

Preparation, Characterization, Hirshfeld surface, Reduced density gradient analysis and transformation of 2,4-dinitroanisole with different crystal forms

The 2,4-dinitroanisole (DNAN) is the new liquid phase carrier used widely in the melt cast explosive. DNAN has two crystal forms and there is relatively little research on two crystal forms. In this article α-DNAN and β-DNAN are prepared by cooling crystallization methods with different cooling rates and subjected to HPLC, IR, DSC, morphology and x-ray single crystal diffraction analysis. The ΔHm of β-DNAN is 17.651 kJ·mol−1 and the ΔHm of α-DNAN is 20.758 kJ·mol−1. According to Hirshfeld surface analysis, β-DNAN has 15.3 % O∙∙∙O contacts and 54.5 % O∙∙∙H contacts, while α-DNAN has 10.6 % O∙∙∙O contacts and 61.8 % O∙∙∙H contacts. The enrichment ratios for all contacts of α-DNAN and β-DNAN are calculated. The total interaction energy from energy framework of β-DNAN and α-DNAN are -107.9 kJ·mol−1 and -201.2 kJ·mol−1. The red color representing steric repulsive interactions is the same and the green color representing van der Waals interactions is different according to RDG analysis of α-DNAN and β-DNAN. From above four perspectives, it been proven that α-DNAN is more batter thermal stability than β-DNAN. The solvent non-solvent method can achieve α-DNAN transformation into β-DNAN. The β-DNAN transformation into α-DNAN is studied at 313.15 K, 323.15 K and 333.15 K. Comparing the two crystal transformation processes, α-DNAN transformation into β-DNAN is difficult, while β-DNAN transformation into α-DNAN is easy to achieve. This indicate crystal stability of β-DNAN is poor, while crystal stability of α-DNAN is good.

Exploring the Corrosion Potential of Three Bio-Based Furan Derivatives on Mild Steel in Aqueous HCl Solution: An Experimental Inquiry Enhanced by Theoretical Analysis.

This research deals with the corrosion inhibition of mild steel in a highly corrosive aqueous HCl medium with a concentration of 0.5 M, using three different corrosion inhibitors: furan-2-carboxylic acid (1), furan-2,5-dicarboxylic acid (2), and furan-2,5-diyldimethanol (3). Various electrochemical tests, such as potentiodynamic polarization (PP or Tafel curve) and electrochemical impedance spectroscopy, were systematically performed. The experimental results underscore the remarkable corrosion mitigating properties of inhibitors 1-3 on mild steel, showing inhibition efficiencies of 97.6, 99.5, and 95.8%, respectively, at a concentration of 5 × 10-3 M and temperature T = 298 K. Notably, the inhibition efficiency of each inhibitor 1-3 shows a positive correlation with its concentration. In addition, consistent results from all electrochemical methods confirm that 1-3 act as mixed inhibitors. These findings remain robust across different experimental techniques, ensuring the reliability and comprehensiveness of the results. Theoretically, the inhibitors were optimized using the Density Functional Theory/B3LYP/6-311++G(d,p) method in gas and aqueous phase to evaluate their reactivity and stability. Among them, compound 2 stands out for its enhanced reactivity and stability, highlighted by optimal EHOMO and ELUMO values. Negative electrostatic potential mapping suggests potential reaction centers, while Fukui functions reveal localized sites of reactivity, supported by a favorable electronic distribution and specific interactions with metal surfaces. Reduced density gradient analysis also confirms the suitability of this compound for noncovalent interactions, in agreement with experimental data.These theoretical results are in good agreement with experimental data, confirming the excellent performance of compound 2 as a corrosion inhibitor.

Novel AIE and solvatochromism exhibiting TPE based organic fluorophore with excellent emission properties in solid and solution phase for latent fingerprint and metronidazole sensing in real samples

Organic molecules with extended aromaticity are important when designing probes with optical properties. Herein, we designed and synthesized a novel tetraphenylethylene (TPE) based organic molecule TC exhibiting excellent photophysical characteristics. A thorough and in-depth study of the optical properties of probe TC was performed including solvatochromism, aggregation and solid-state studies using ultraviolet–visible (UV Vis) and fluorescence spectroscopy. Also, its optical properties under a UV 365 nm laser were investigated. The compound exhibited aggregation induced emission (AIE) which was thoroughly investigated in a H2O/DMF system and later utilized in formulation of invisible ink and latent fingerprint sensing. Moreover, the excellent emission properties of probe TC were utilized for the highly selective detection of the antibiotic metronidazole (MET) in real samples including human serum and artificial urine. Furthermore, portable TLC and paper-based strips were designed for the on-site detection of MET. Additionally, the mechanism of selective sensing of MET was thoroughly investigated through spectroscopic studies including titration NMR, fluorescence, UV Vis studies and DFT studies. Photoinduced electron transfer (PET) was attributed as the plausible sensing mechanism for the detection of MET. Scanning electron microscopy (SEM) also supported the sensing of MET through change in morphology. DFT calculations involved the measurement of thermodynamic stability, reduced density gradient (RDG) analysis, molecular orbital, and charge transfer studies as well as analysis of quantum theory of atoms in molecules (QTAIM). All the studies supported the presence of non-covalent interactions between probe TC and MET.

Synthesis, spectroscopic characterization, electronic elucidation, chemical reactivity, topological and molecular docking investigations of cefadroxil sulfoxide

The cefadroxil sulfoxide (CDSO) para-hydroxy derivative, derived from cefadroxil, has enormous significance in pharmaceutical applications. The cefadroxil sulfoxide (CDSO) compound was synthesized and characterized by spectroscopic (FT-IR, FT-Raman, and UV–Visible) assessments. Computational investigations have been carried out concurrently with a B3LYP-6-311++G(d,p) basis set and density functional theory (DFT). The molecular vibrational assignments, chemical reactivity, electronic properties, and optical activities are calculated using gas and different solvent phases. The stable ground state configuration of the given molecular compound is investigated using PES analysis. Furthermore, the chemical behavior of the CDSO was thoroughly investigated for different solvent aspects through HOMO-LUMO, MEP, UV–Visible and electron-hole excitation analyses. The molecular occupancy, virtual occupancy, and overlapping bonding energies are investigated by TDOS, PDOS, and COOP spectrum studies. Fukui function and dual descriptor investigations extend to the chemical reactivity of individual atomic sites. The intra-molecular analysis provided a deeper understanding of the molecular interactions performed by natural bond orbitals (NBO) and non-linear optics (NLO), which provided optical activity for the title compound. Additionally, electron localization function (ELF), localized orbital locator (LOL), and reduced density gradient (RDG) analyses were also accomplished to provide insight into the delocalized orbitals in the header composite. The molecular docking was achieved, and the ligand with 4EVM protein is providing the potential antimicrobial biological activity (binding energy −7.12 kcal/mol) of the CDSO compound.

Interaction between Halogenated Phenols and Thyroxine‐Binding Protein: A Multispectral and Computational Approach

AbstractThe aim of this study was to understand the interaction between transthyretin (TTR) and halogenated phenols (HPs) including 2,4‐dichlorophenol (DCP), 2,4,6‐trichlorophenol (TCP), pentachlorophenol (PCP), 2‐bromophenol (2‐BP), 2,4‐dibromophenol (DBP) and 2,4,6‐tribromophenol (TBP). Computer simulation and multi‐spectroscopy techniques were used to investigate the interaction. The fluorescence of TTR was found to be quenched through static quenching and non‐radiative energy transfer by HPs, suggesting that the binding process between HPs and TTR was primarily influenced by van der Waals forces and hydrogen bonds. ANS substitution experiments indicated that HPs interacted with TTR at the T4 binding site. Three‐dimensional fluorescence spectra and Fourier transform infrared spectroscopy were used to investigate the conformational and microenvironmental changes of TTR resulting from the interactions with HPs. Additionally, molecular docking and reduced density gradient analysis were used to identify the specific residues and binding forces involved in the interaction between HPs and TTR binding sites. The findings were subsequently validated through quantum chemical analysis. This research integrates state‐of‐the‐art multispectral analytical methodologies with sophisticated computational modeling to introduce an innovative approach for dissecting the interactions between halogenated phenols (HPs) and transthyretin (TTR). This methodology offers a novel avenue for investigating the molecular interplay between HPs and TTR, thereby providing critical insights that are instrumental in assessing the latent toxicity of these compounds.

Guanidinium and spermidinium decavanadates: as small biomimetic models to understand non-covalent interactions between decavanadate and arginine and lysine side chains in proteins

During the last three decades, numerous investigations have been conducted on polyoxidovanadates to treat several illnesses and inhibit enzymes. Numerous decavanadate compounds have been proposed as potential therapies for Diabetes mellitus, Cancer, and Alzheimer’s disease. Only six relevant functional proteins interacting with decavanadate, V10, have been deposited in the PDB. These are acid phosphatase, tyrosine kinase, two ecto-nucleoside triphosphate diphosphohydrolases (NTPDases), the human transient receptor potential cation channel (TRPM4), and the human cell cycle protein CksHs1. The interaction sites in these proteins mainly consist of Arginine and Lysine, side chains binding to the decavanadate anion. To get further knowledge regarding non-covalent interactions of decavanadate in protein environments, guanidinium and spermidinium decavanadates were synthesized, crystallized, and subjected to analysis utilizing various techniques, including FTIR, Raman, 51V-NMR, TGA, and X-ray diffraction. The DFT calculations were employed to calculate the interaction energy between the decavanadate anion and the organic counterions. Furthermore, the Quantum Theory of Atoms in Molecules (QTAIM) and Non-covalent Interaction-Reduced Density Gradient (NCI-RDG) analyses were conducted to understand the non-covalent interactions present in these adducts. Decavanadate can engage in electrostatic forces, van der Waals, and hydrogen bond interactions with guanidinium and spermidinium, as shown by their respective interaction energies. Both compounds were highly stabilized by strong hydrogen bond interactions N−H···O and weak non-covalent interactions C−H···O. In addition, the interactions between guanidinium and spermidinium cations and decavanadate anion form several stable rings. This study provides new information on non-covalent intermolecular interactions between decavanadate and small biomimetic models of arginine and lysine lateral chains in protein environments.