Synthesis, Characterization, Antimicrobial, Density Functional Theory, and Molecular Docking Studies of Novel Mn(II), Fe(III), and Cr(III) Complexes Incorporating 4-(2-Hydroxyphenyl azo)-1-naphthol (Az)

Thiadiazole/Thiadiazine Derivatives as Insecticidal Agent: Design, Synthesis, and Biological Assessment of 1,3,4-(Thiadiazine/Thiadiazole)-Benzenesulfonamide Derivatives as IGRs Analogues against Spodoptera littoralis

In keeping with our investigation, a simple and practical synthesis of novel heterocyclic compounds with a sulfamoyl moiety that can be employed as insecticidal agents was reported. The compound 2-hydrazinyl-N-(4-sulfamoylphenyl)-2-thioxoacetamide 1 was coupled smoothly with triethylorthoformate or a variety of halo compounds, namely phenacyl chloride, chloroacetyl chloride, chloroacetaldehyde, chloroacetone, 1,3-dichloropropane, 1,2-dichloroethane, ethyl chloroformate, 2,3-dichloro-1,4-naphthoquinone, and chloroanil respectively, which afforded the 1,3,4-thiadiazole and 1,3,4-thiadiazine derivatives. The new products structure was determined using elemental and spectral analysis. Under laboratory conditions, the biological and toxicological effects of the synthetic compounds were also evaluated as insecticides against Spodoptera littoralis (Boisd.). Compounds 3 and 5 had LC50 values of 6.42 and 6.90 mg/L, respectively. The investigated compounds (from 2 to 11) had been undergoing molecular docking investigation for prediction of the optimal arrangement and strength of binding between the ligand (herein, the investigated compounds (from 2 to 11)) and a receptor (herein, the 2CH5) molecule. The binding affinity within docking score (S, kcal/mol) ranged between -8.23 (for compound 5), -8.12 (for compound 3) and -8.03 (for compound 9) to -6.01 (for compound 8). These compounds were shown to have a variety of binding interactions within the 2CH5 active site, as evidenced by protein-ligand docking configurations. This study gives evidence that those compounds have 2CH5-inhibitory capabilities and hence may be used for 2CH5-targeting development. Furthermore, the three top-ranked compounds (5, 3, and 9) and the standard buprofezin were subjected to density functional theory (DFT) analysis. The highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) energy difference (ΔE) of compounds 5, 3, and 9 was found to be comparable to that of buprofezin. These findings highlighted the potential and relevance of charge transfer at the molecular level.

Electronic analysis of n-propyl xanthate complexes with group 12 metals: a theoretical-experimental study

CONTEXT

Xanthates are organic compounds of great interest in coordination chemistry due to their different basic sites, which allow them to form complexes with different coordination modes and geometries. These compounds are relevant in the environment and act as heavy metal collectors in aqueous environments. In this theoretical-experimental work, electronic spectroscopy studies of n-propyl xanthate complexes with group 12 metals were performed. This study verified structural differences in these systems, depending on the environment in which they are inserted. In addition, structural differences were observed when the solid was changed to an n-hexane solution. Thus, it was observed that the complexes assume a mononuclear structure in solution, while they present a polymeric form in the solid phase. The electronic spectra obtained through TD-DFT calculations were compared to those of the previously synthesized complexes. In the final theoretical analysis, the main orbitals involved in these transitions were assigned using population analysis calculations. The synthesis of the complexes was confirmed through infrared (MID and FAR), UV‒Vis, Raman, and NMR-1H spectroscopic analyses.

METHODS

The structures of the mononuclear and polymeric complexes were optimized in vacuum and n-hexane. Under vacuum, DFT levels M06L/6-311 + + G** + LANL2TZ and M06L/def2-TZVP were used for the mononuclear complexes, and M06L/LANL2DZ + LANL2 were used for the polymer complexes. For the calculations of the mononuclear complexes in n-hexane, the same level of theory was used for the solid state. TD-DFT calculations for 300 excited states were performed with the same levels of theory and used the optimized structures of the complexes. Furthermore, population analysis was carried out on all the systems studied. Gaussian 09 software was used for the structure optimization, TD-DFT, and population analysis calculations. GaussSum software was used to evaluate the molecular orbitals and electronic spectra.

Designing, DFT, biological, & molecular docking analysis of new Iron(III) & copper(II) complexes incorporating 1-{[-(2-Hydroxyphenyl)methylene]amino}-5,5-diphenylimidazolidine-2,4-dione (PHNS)

The exploration encompassed the synthesis and characterization of two innovative complexes, namely FePHNS and CuPHNS, employing a diverse array of analytical techniques such as elemental analysis, infrared and ultraviolet-visible spectroscopy, mass spectrometry, molar conductivity measurements, magnetic susceptibility assessments, and thermal analysis (TGA). In the spectral domain, infrared spectroscopy substantiated the tridentate ONS coordination of the PHNS ligand to the central metal atom. Thermal analysis offered valuable insights into the distribution and content of water molecules within the complexes. Density functional theory (DFT) calculations were harnessed to validate the molecular structures of both the PHNS ligand and its complex entities, providing an intricate comprehension of their quantum chemical parameters. The investigation extended to an evaluation of the in vitro antibacterial, antifungal, and antioxidant efficacy of the PHNS ligand and its complexes, revealing heightened biological activities for the complexes in comparison to the free PHNS ligand, notably with the CuPHNS complex demonstrating the highest activity, while the PHNS ligand exhibited the lowest. To delve into potential physiological activities, molecular docking studies were conducted, predicting the binding affinity of the compounds to proteins 2vf5 (Glucosamine-6-phosphate synthase in complex with glucosamine-6-phosphate) from Escherichia coli, 3cku (rate oxidase from Aspergillus flavus complexed with its inhibitor 8-azaxanthin and chloride) from Aspergillus flavus, and 5IJT (Crystal structure of Human Peroxiredoxin 2 Oxidized). The ensuing analysis of protein-ligand interactions and binding energies underscored the promising physiological activities of the investigated compounds, warranting further exploration for their potential in novel drug development.

A selective colorimetric chemosensor for detecting Ni(II) in aqueous solutions based on 4-[{[4-(3-chlorophenyl)-1,3-thiazol-2-yl]hydrazono}methyl]phenyl 4-methyl benzene sulfonate (CTHMBS)

Among the toxic heavy metals, Ni(II) can cause a variety of side effects on human health, such as allergy, cardiovascular and kidney diseases, lung fibrosis, lung, and nasal cancer. It is therefore critical from a public health and environmental perspective to determine and monitor Ni(II) ions in drinking water, foods, and environmental samples. In this study, a novel selective chemosensor (4-[{[4-(3-Chlorophenyl)-1,3-Thiazol-2-yl]Hydrazono}Methyl]phenyl4-methylBenzene Sulfonate (CTHMBS) was developed for the colorimetric detection of Ni(II) in aqueous medium. The presence of Ni(II) led to a distinct naked-eye color change from yellow to reddish-brown in aqueous solution. To examine the binding mechanism of CTHMBS to Ni(II), UV-vis spectroscopy analysis and DFT calculations were conducted. The detection limit of CTHMBS for Ni(II) was 11.87 µM, and the sensing ability of CTHMBS for Ni(II) was successfully carried out in real water samples.

Designing, Characterization, DFT, Biological Effectiveness, and Molecular Docking Analysis of Novel Fe(III), Co(II), and Cu(II) Complexes Based on 4-Hydroxy-2H-pyrano[3,2-c]quinoline-2,5(6H)-dione

The main target of the current framework is the designing and synthesizing of novel iron(III), cobalt(II), and cupper(II) complex compounds emanating from bioactive nucleus, 4-hydroxy-2H-pyrano[3,2-c]quinoline-2,5(6H)-dione ligand, to enhance comprehension as potential antibacterial, antifungal, and antioxidant alternatives by means of using DFT calculations and molecular docking investigation. Thus, the new complexes had been synthesized and characterized using various analytical techniques, including elemental analysis, infrared spectroscopy, mass spectrometry, UV spectroscopy, conductivity, and magnetic testing, as well as thermal analysis. The 4-hydroxy-2H-pyrano[3,2-c]quinoline-2,5(6H)-dione ligand exhibits monobasic bidentate OO donor properties toward the metal core, as shown by its infrared spectroscopic characteristics. The use of thermal analysis techniques allows for the identification and characterization of water molecules present inside the complexes, as well as the determination of their distribution patterns. The molecular structures of free ligand and its metal complex compounds have been verified through the use of density functional theory (DFT) simulations. These simulations also provide a valuable understanding of the quantum chemical characteristics associated with these structures. In vitro experiments were conducted to evaluate the antioxidant, antibacterial, as well as antifungal and the properties of the free ligand and its corresponding complex compounds. DATA revealed that synthesized metal complex compounds have heightened biological efficacy as related to the unbound ligand. Furthermore, molecular docking analysis was done to understand the interactions between the studied compounds and proteins derived from Escherichia coli (pdb ID: 2vf5), Aspergillus flavus (pdb ID: 3cku), and humans (pdb ID: 5IJT), which are considered to be significant in drug design. Lastly, a correlation between in vitro efficacies with molecular docking data was done and analyzed.

An efficient eco-friendly, simple, and green synthesis of some new spiro-N-(4-sulfamoyl-phenyl)-1,3,4-thiadiazole-2-carboxamide derivatives as potential inhibitors of SARS-CoV-2 proteases: drug-likeness, pharmacophore, molecular docking, and DFT exploration

INTRODUCTION

The coronavirus disease 2019 (COVID-19) pandemic has caused a global health crisis. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly contagious virus that can cause severe respiratory illness. There is no specific treatment for COVID-19, and the development of new drugs is urgently needed.

PROBLEM STATEMENT

The SARS-CoV-2 main protease (Mpro) enzyme is a critical viral enzyme that plays a vital role in viral replication. The inhibition of Mpro enzyme can be an effective strategy for developing new COVID-19 drugs.

METHODOLOGY

An efficient operationally simple and convenient green synthesis method had been done towards a series of novel spiro-N-(4-sulfamoylphenyl)-2-carboxamide derivatives, in ethanol at room temperature in green conditions, up to 90% yield. The molecular structures of the synthesized compounds were verified using spectroscopic methods.The title compounds were subjected to in silico analysis, including Lipinski's rule and ADMET prediction, in addition to pharmacophore modeling and molecular docking against the active site of SARS-CoV-2 target main protease (Mpro) enzyme (6LU7). Furthermore, both of the top-ranked compounds (5 and 6) and the standard Nirmatrelvir were subjected to DFT analysis.

FINDINGS

The synthesized compounds exhibited good binding affinity to SARS-CoV-2 Mpro enzyme, with binding energy scores ranging from - 7.33 kcal/mol (compound 6) and - 7.22kcal/mol (compound 5) to - 6.54 kcal/mol (compounds 8 and 9). The top-ranked compounds (5 and 6) had lower HOMO-LUMO energy difference (ΔE) than the standard drug Nirmatrelvir. This highlights the potential and relevance of charge transfer at the molecular level.

RECOMMENDATION

These findings suggest that the synthesized spiro-N-(4-sulfamoylphenyl)-2-carboxamide derivatives could be potential candidates for COVID-19 drug development. To confirm these drugs' antiviral efficacy in vivo, more research is required. With very little possibility of failure, this proven method could aid in the search for the SARS-CoV-2 pandemic's desperately needed medications.

Synthesis, Characterizations, and Quantum Chemical Investigations on Imidazo[1,2-a]pyrimidine-Schiff Base Derivative: (E)-2-Phenyl-N-(thiophen-2-ylmethylene)imidazo[1,2-a]pyrimidin-3-amine

In this study, (E)-2-phenyl-N-(thiophen-2-ylmethylene)imidazo[1,2-a]pyrimidin-3-amine (3) is synthesized, and detailed spectral characterizations using 1H NMR, 13C NMR, mass, and Fourier transform infrared (FT-IR) spectroscopy were performed. The optimized geometry was computed using the density functional theory method at the B3LYP/6-311++G(d,p) basis set. The theoretical FT-IR and NMR (1H and 13C) analysis are agreed to validate the structural assignment made for (3). Frontier molecular orbitals, molecular electrostatic potential, Mulliken atomic charge, electron localization function, localized orbital locator, natural bond orbital, nonlinear optical, Fukui functions, and quantum theory of atoms in molecules analyses are undertaken and meticulously interpreted, providing profound insights into the molecular nature and behaviors. In addition, ADMET and drug-likeness studies were carried out and investigated. Furthermore, molecular docking and molecular dynamics simulations have been studied, indicating that this is an ideal molecule to develop as a potential vascular endothelial growth factor receptor-2 inhibitor.