Synthesis of Schiff base (E)-4-((2-hydroxy-3,5-diiodobenzylidene)amino)-N-thiazole-2-yl)benzenesulfonamide with antimicrobial potential, structural features, experimental biological screening and quantum mechanical studies

J P, Harohally NV, Krishnamurthy C, Jathi K, Ahmad A, Alshammari MB, Lokanath NK. Structural Investigation of Schiff Base Ligand and Dinuclear Copper Complex: Synthesis, Crystal Structure, Computational, and Latent Fingerprint Analysis

The structural studies of the fluorinated Schiff base ligand and its copper complex were synthesized and characterized by Fourier transform infrared, UV-visible, and photoluminescence spectroscopy. Single-crystal X-ray diffraction analysis unveils a dinuclear copper complex arising from double bridging acetate anions to copper ions that are chelated by the tridentate Schiff base ligand Cu(LS). The trigonality index τ5 of 0.080 indicates a distorted square pyramidal coordination geometry for the metal. The SL ligand and complex exhibit intra- and intermolecular interactions, leading to unique supramolecular architectures. The structural changes between the free halogenated Schiff base ligand and upon coordination with the metal were extensively studied by experimental and theoretical approaches. The intra- and intermolecular interactions have been analyzed by Hirshfeld surface and quantum theory of atoms in molecules analysis, and the enrichment ratio highlights the most favored interactions in the formation of molecular packing. The chemical and physical properties, such as the HOMO - LUMO energy gap, chemical reactivity, and electron density topology, are studied using density functional theory studies. In addition, the Schiff base ligand compound is used to study the latent fingerprint analysis.

Advances in Organosulfur-Based Polymers for Drug Delivery Systems

Organosulfur-based polymers have unique properties that make them useful for targeted and managed drug delivery, which can improve therapy while reducing side effects. This work aims to provide a brief review of the synthesis strategies, characterization techniques, and packages of organosulfur-based polymers in drug delivery. More importantly, this work discusses the characterization, biocompatibility, controlled release, nanotechnology, and targeted therapeutic aspects of these important structural units. This review provides not only a good comprehension of organosulfur-based polymers but also an insightful discussion of potential future prospectives in research. The discovery of novel organosulfur polymers and innovations is highly expected to be stimulated in order to synthesize polymer prototypes with increased functional accuracy, efficiency, and low cost for many industrial applications.

Comparison study (experimental and theoretical), hydrogen bond interaction through water, donor acceptor investigation and molecular docking study of 3,3-((1,2-phenylenebis (azaneylylidene)) bis (methaneylylidene)) diphenol

The novel Schiff's base (CS6) was synthesized and confirmed by various studies. The B3LYP/cc-pVDZ basis set was used for theoretical study and the results indicated that both the theoretical and experimental studies correlated well. The interaction energy of CS6-water complex calculated by using the local energy decomposition analysis was found to be -7.28 kcal/mol. The TD-TFT method was used for the calculation of electronic absorption spectrum. This study confirmed that the observed wavelength and the simulated wavelength in the electronic spectra were almost similar. The electrophilic and nucleophilic attacking sites of the titled compound were identified by using FMO and MEP studies. The highest stabilization energy (30.19 kcal/mol) formed by LP (2) O24 to anti-bonding σ*(C18-C19) was confirmed by the NBO study. The localized and delocalized electrons were confirmed by ELF and LOL studies. The hydrogen bond interaction as well as the physical and chemical properties of CS6 indicated that it showed a moderate similarity to the drugs. The docking study confirmed that the dehydro-L-gulonate decarboxylase inhibitor (1Q6O) could interact with CS6 compound with the binding energy of -5.26 kcal/mol.Communicated by Ramaswamy H. Sarma.

Synthesis and Spectroscopic Characterization of Schiff Base Metal Complexes, Biological Activity, and Molecular Docking Studies

New cobalt(II), copper(II), and zinc(II) Schiff metal complexes were synthesized by the condensation reaction of 4-nitrobenzene-1,2-diamine with 3-4-(diethylamino)-2-hydroxybenzaldehyde. Fourier transform infrared, nuclear magnetic resonance, ultraviolet-visible, electron paramagnetic resonance, and high-resolution electrospray ionization mass spectrometry and powder X-ray diffraction were used to characterize the synthesized H2L and its metal complexes. Conductance measurements, magnetic moment estimation, and metal estimation have all been determined and discussed. The electrochemical properties of the synthesized compounds have been determined and discussed using cyclic voltammetry. The molecular structures of H2L and its metal complexes have been optimized using the B3LYP functional and the 6-31G (d,p) basis set, and their parameters have been discussed. The quantum chemical properties of these synthesized compounds have been predicted through charge distribution and molecular orbital analysis. The biological properties of the synthesized compounds' antioxidant, antifungal, and antibacterial activity have been studied and discussed. Furthermore, H2L and its complexes have been docked with HER2-associated target proteins in breast cancer.

Antimicrobial activity prediction, inter- and intramolecular charge transfer investigation, reactivity analysis and molecular docking studies of adenine derivatives

The utilization of the density functional theory (DFT) methodology has developed as a highly efficient method for investigating molecular structure and vibrational spectra, and it is increasingly being employed in various applications relating to biological systems. This study focuses on conducting investigations, both experimental and computed, to analyze the molecular structure, electronic properties and features of (E)-4-(((9H-purin-6-yl)imino)methyl)-2-methoxyphenol (ANVA). The expression ANVA should be rewritten as follows: the compound is a derivative of adenine (primary amine), specifically a vanillin (aldehyde). The present study reports the synthesis, characterization, DFT, docking and antimicrobial activity of ANVA. The optimization of the molecular structure was conducted, and the determination of its structural features was performed using DFT with the B3LYP/cc-pVDZ method. The vibrational assignments were determined in detail by analyzing the potential energy distribution. A strong correlation was observed between the spectra that were observed and the spectra that were calculated. The calculation of intramolecular charge transfer was performed using natural bond orbital analysis. In addition, several computational methods were employed, including highest occupied molecular orbital-least unoccupied molecular orbital analysis, molecular electrostatic potential calculations, non-linear optical, reduced density gradient, localization orbital locator and electron localization function analysis. This paper examines the present use of adenine derivatives in combatting bacterial and fungal infections, as well as the inclusion of spectral and quantum chemical calculations in the discussion.Communicated by Ramaswamy H. Sarma.

A novel cobalt(ii) acetate complex bearing lutidine ligand: a promising electrocatalyst for oxygen evolution reaction

Developing cost-effective electrocatalysts using earth-abundant metal as an alternative to expensive precious metal catalyst remains a key challenge for researchers. Several strategies are being researched/tested for making low-cost transition metal complexes with controlled electron-density and coordination flexibility around the metal center to enhance their catalytic activity. Herein, we report a novel lutidine coordinated cobalt(ii) acetate complex [(3,5-lutidine)2Co(OAc)2(H2O)2] (1) as a promising electrocatalyst for oxygen evolution reaction (OER). Complex 1 was characterized by FT-IR, elemental analysis, and single crystal X-ray diffraction data. The structure optimization of complex 1 was also done using DFT calculation and the obtained geometrical parameters were found to be in good agreement with the parameters obtained from the solid state structure obtained through single crystal X-ray diffraction data. Further, the molecular electrostatic potential (MEP) maps analysis of complex 1 observed electron rich centers that were found to be in agreement with the solid-state structure. It was understood that the coordination of lutidine as a Lewis base and acetate moiety as a flexible ligand will provide more coordination flexibility around the metal center to facilitate the catalytic reaction. Further, the electron rich centers around metal center will also support the enhancement of their catalytic activity. Complex 1 shows impressive OER activity, even better than the state-of-the-art IrO2 catalyst, in terms of turnover frequency (TOF: 0.05) and onset potential (1.50 V vs. RHE). The TOF for complex 1 is two and half times higher, while the onset potential is ca. 20 mV lower, than the benchmark IrO2 catalyst studied under identical conditions.

(8-Hydroxyquinoline) Gallium(III) Complex with High Antineoplastic Efficacy for Treating Colon Cancer via Multiple Mechanisms

A series of (8-hydroxyquinoline) gallium(III) complexes (CP-1-4) was synthesized and characterized by single X-ray crystallography and density functional theory (DFT) calculation. The cytotoxicity of the four gallium complexes toward a human nonsmall cell lung cancer cell line (A549), human colon cancer cell line (HCT116), and human normal hepatocyte cell line (LO2) was evaluated using MTT assays. CP-4 exhibited excellent cytotoxicity against HCT116 cancer cells (IC₅₀ = 1.2 ± 0.3 μM) and lower toxicity than cisplatin and oxaliplatin. We also evaluated the anticancer mechanism studies in cell uptake, reactive oxygen species analysis, cell cycle, wound-healing, and Western blotting assays. The results showed that CP-4 affected the expression of DNA-related proteins, which led to the apoptosis of cancer cells. Moreover, molecular docking tests of CP-4 were performed to predict other binding sites and to confirm its higher binding force to disulfide isomerase (PDI) proteins. The emissive properties of CP-4 suggest that this complex can be used for colon cancer diagnosis and treatment, as well as in vivo imaging. These results also provide a foundation for the development of gallium complexes as potent anticancer agents.

Synthesis of Novel Indole Schiff Base Compounds and Their Antifungal Activities

A series of novel indole Schiff base derivatives (2a–2t) containing a 1,3,4-thiadiazole scaffold modified with a thioether group were synthesized, and their structures were confirmed using FT-IR, ¹H NMR, ¹³C NMR, and HR-MS. In addition, the antifungal activity of synthesized indole derivatives was investigated against Fusarium graminearum (F. graminearum), Fusarium oxysporum (F. oxysporum), Fusariummoniliforme (F.moniliforme), Curvularia lunata (C. lunata), and Phytophthora parasitica var. nicotiana (P. p. var. nicotianae) using the mycelium growth rate method. Among the synthesized indole derivatives, compound 2j showed the highest inhibition rates of 100%, 95.7%, 89%, and 76.5% at a concentration of 500 μg/mL against F. graminearum, F. oxysporum, F.moniliforme, and P. p. var. nicotianae, respectively. Similarly, compounds 2j and 2q exhibited higher inhibition rates of 81.9% and 83.7% at a concentration of 500 μg/mL against C. lunata. In addition, compound 2j has been recognized as a potential compound for further investigation in the field of fungicides.

Synthesis, characterization, and theoretical investigation of 4-chloro-6(phenylamino)-1,3,5-triazin-2-yl)asmino-4-(2,4-dichlorophenyl)thiazol-5-yl-diazenyl)phenyl as potential SARS-CoV-2 agent

The synthesis of 4-chloro-6(phenylamino)-1,3,5-triazin-2-yl)amino-4-(2,4 dichlorophenyl)thiazol-5-yl-diazenyl)phenyl is reported in this work with a detailed structural and molecular docking study on two SARS-COV-2 proteins: 3TNT and 6LU7. The studied compound has been synthesized by the condensation of cyanuric chloride with aniline and characterized with various spectroscopic techniques. The experimentally obtained spectroscopic data has been compared with theoretical calculated results achieved using high-level density functional theory (DFT) method. Stability, nature of bonding, and reactivity of the studied compound was evaluated at DFT/B3LYP/6-31 + (d) level of theory. Hyper-conjugative interaction persisting within the molecules which accounts for the bio-activity of the compound was evaluated from natural bond orbital (NBO) analysis. Adsorption, Distribution, Metabolism, Excretion and Toxicity (ADMET) properties of the experimentally synthesized compound was studied to evaluate the pharmacological as well as in silico molecular docking against SARS-CoV-2 receptors. The molecular docking result revealed that the investigated compound exhibited binding affinity of −9.3 and −8.8 for protein 3TNT and 6LU7 respectively. In conclusion, protein 3TNT with the best binding affinity for the ligand is the most suitable for treatment of SARS-CoV-2.