Synthesis and intensive characterization for novel Zn(II), Pd(II), Cr(III) and VO(II)-Schiff base complexes; DNA-interaction, DFT, drug-likeness and molecular docking studies

Design, spectral characterization, quantum chemical investigation, biological activity of nano-sized transition metal complexes of tridentate 3-mercapto-4H-1,2,4-triazol-4-yl-aminomethylphenol Schiff base ligand

A tridentate Schiff base ligand, H2MTIP, was produced by condensing salicylaldehyde with 4-amino-4H-1,2,4-triazole-3-thiol. The ligand was then used to create nanosized complexes of Pt(II), Ni(II), Cu(II), and Pd(II). The complexes have the composition [Pt/Ni/Cu/or Pd(MTIP)(H2O)], this conclusion is supported by molar conductance, magnetic moments, elemental analyses, spectral analyses. In DFT analysis, the 6-31+ g(d,p) basis set was used to fully optimize the energy with respect to the shapes of Schiff base ligand and metal complexes. Pt(II), Ni(II), Cu(II), and Pd(II) complexes have been assigned square-planar geometries. At the same time, the intense diffraction peaks in X-ray diffractograms show their crystalline features with particle sizes in the nanoscale range. The binding interaction of calf thymus DNA with these metal complexes and their insulin-like activity was examined in vitro by inhibiting α-amylase. The study investigated the in-vitro activity of several complexes and identified Pt(II) complex as the one with the highest activity. The researchers then tested this complex for in-vivo antidiabetic activity in induced diabetic rats using the STZ model, and it significantly lowered blood glucose levels. The antioxidant activity and toxicity level of Pt(II) complex were also excellent, suggesting that it could be a good candidate for further research as a possible diabetes drug.Communicated by Ramaswamy H. Sarma.

Structural Characteristics and DNA Groove Binding Abilities of Two Zinc-Based Isoreticular MOFs

In this study, we have synthesized two zinc(II)-based metal-organic frameworks (MOFs) designated as [Zn(4-nvp)(bdc)] ⋅ (MeOH) (1) and [Zn2(4-nvp)2(bpdc)2] ⋅ (DMF) (2) [4-nvp=4-(1-naphthylvinyl) pyridine, H2bdc=1,4-benzendicarboxylic acid and H2bpdc=4,4'-biphenyldicarboxylic acid]. Single-crystal X-ray diffraction (SCXRD) of both compounds unveiled an interesting paddle-wheel [Zn2(O2C-C)4] secondary building block (SBB) composed of dinuclear Zn (II) centers and four dicarboxylate groups with a (4,4) square grid topology. These SBBs are interconnected giving rise to an infinite 2D layer architecture. Notably, the grid structure is composed of MeOH molecules in compound 1 and DMF molecules in compound 2, both of them arranged in a free lattice. In both compounds, 3D supramolecular architecture is ultimately formed through the stacking of 2D layers. Since the length of the bpdc ligand is higher than that of the bdc ligand, the solvent-accessible void volume is comparatively higher for compound 2. To corroborate all non-bonded interactions, Hirshfeld analysis was carried out for synthesized compounds. DNA binding application was extensively investigated through docking study. Results indicated that the synthesized compounds have strong affinities towards DNA via DNA groove binding. Henceforth, the synthesized compounds 1 and 2 would open the door for their potential applications as particular protein binders and bioactive substances.

Spectroscopic, anti-cancer, anti-bacterial and theoretical studies of new bivalent Schiff base complexes derived from 4-bromo-2,6-dichloroaniline

In this paper, four new mono-nuclear Ni(II), Pd(II), Pt(II) and Zn(II) complexes were prepared by using a bi-dentate Schiff base ligand, (E)-2-(((4-bromo-2,6-dichlorophenyl)imino)methyl)-5-chlorophenol (BrcOH), with bivalent ions in a methanol and distil water mixture as solvent in presence of NaOH as base. The structures of the prepared compounds were characterized by spectroscopic techniques (IR and 1H NMR), CHN analysis, and molar conductivity. The M(II) (Ni, Pd and Pt) ions are four-coordinated by a bi-dentate N2O2 donor ligand, forming square planar geometry, whereas the Zn(II) is coordinated as a tetrahedral geometry. The newly synthesized compounds, which include the Schiff base ligand and its complexes, underwent antibacterial screening against E. coli and S. aureus. The results demonstrated a remarkable and noteworthy biological activity of these compounds against these pathogenic bacterial strains. Different binding energies showed good correlation, with Pd showing the strongest binding. Small energy differences indicated high reactivity, with Ni and Pd complexes being the most reactive. Electrophilicity index exhibited electron-accepting properties, with Zn showing the highest reactivity. The dipole moments showed polarity and charge separation, with Pt having the highest polarity. We evaluated the pharmacokinetic properties (ADME) of a ligand and its metal complexes using the Swiss ADME website. The results of the in-silico prediction of physicochemical properties revealed that ten compounds in total adhered to Lipinski's rule.

Computational and experimental examinations of new antitumor palladium(II) complex: CT-DNA-/BSA-binding, in-silico prediction, DFT perspective, docking, molecular dynamics simulation and ONIOM

Since the design of metal complexes with better biological activities is important, herein a new palladium(II) complex bearing en and acac (en and acac stand for ethylenediamine and acetylacetonato, respectively) as its ligands, [Pd(en)(acac)]NO3 complex, was synthesized and fully characterized. Quantum chemical computations of the palladium(II) complex were done via DFT/B3LYP method. Cytotoxicity activity of the new compound on leukemia cell line (K562) was assessed via MTT method. The findings indicated that the metal complex has remarkable cytotoxic effect than cisplatin. OSIRIS DataWarrior software was employed to calculate in-silico physicochemical and toxicity parameters of the synthesized complex which rendered significant results. To comprehend the interaction type of new metal compound with macromolecules, the in depth investigation of interaction of mentioned complex with CT-DNA and BSA was accomplished by fluorescence, UV-Visible absorption spectroscopy, viscosity measurement, gel electrophoresis, FRET analysis and circular dichroism (CD) spectroscopy. On the other hand, computational molecular docking was carried out and the obtained data demonstrated that H-bond and van der Waals forces are the dominant forces for the binding of the compound to the mentioned biomolecules. Molecular dynamics simulation was also done and confirmed the stability of best docked pose of palladium(II) complex inside DNA or BSA over the time and in presence of water solvent. Also, Our own N-layered Integrated molecular Orbital and molecular Mechanics (ONIOM) methodology based on the hybridization of quantum mechanics and molecular mechanics (QM/MM) methodology was accomplished to inquire about binding of Pd(II) complex with DNA or BSA.HIGHLIGHTSNew biologically active Pd(II) complex was synthesized and characterized.The in silico studies of the designed complex and its ligands were accomplished by OSIRIS DataWarrior softwareInteraction with CT-DNA and BSA was assessed by various spectroscopic methods.Molecular docking simulation supported the interaction with both macromolecules.Based on ONIOM analysis, the structures of the complex and biomolecules are altered after binding. Communicated by Ramaswamy H. Sarma.

Exploring optimal drug targets through subtractive proteomics analysis and pangenomic insights for tailored drug design in tuberculosis

Tuberculosis (TB), caused by Mycobacterium tuberculosis, ranks among the top causes of global human mortality, as reported by the World Health Organization's 2022 TB report. The prevalence of M. tuberculosis strains that are multiple and extensive-drug resistant represents a significant barrier to TB eradication. Fortunately, having many completely sequenced M. tuberculosis genomes available has made it possible to investigate the species pangenome, conduct a pan-phylogenetic investigation, and find potential new drug targets. The 442 complete genome dataset was used to estimate the pangenome of M. tuberculosis. This study involved phylogenomic classification and in-depth analyses. Sequential filters were applied to the conserved core genome containing 2754 proteins. These filters assessed non-human homology, virulence, essentiality, physiochemical properties, and pathway analysis. Through these intensive filtering approaches, promising broad-spectrum therapeutic targets were identified. These targets were docked with FDA-approved compounds readily available on the ZINC database. Selected highly ranked ligands with inhibitory potential include dihydroergotamine and abiraterone acetate. The effectiveness of the ligands has been supported by molecular dynamics simulation of the ligand-protein complexes, instilling optimism that the identified lead compounds may serve as a robust basis for the development of safe and efficient drugs for TB treatment, subject to further lead optimization and subsequent experimental validation.

Synthesis and Characterization of Zn(II) Complex of 4-chloro-2-(((2-phenoxyphenyl)imino)methyl)phenol and its Biological Efficacies: DNA Interaction, ADMET, DFT and Molecular Docking Study

Condensing 2-phenoxyaniline with 5-chlorosalicyldehyde under reflux conditions, a 4-chloro-2-(((2-phenoxyphenyl)imino)methyl)phenol Schiff base has been Synthesized. A zinc complex was synthesized by combining the ligand in a 1:1 molar ratio with zinc sulphateheptahydrate. Mass spectroscopy, NMR, infrared, and elemental analysis were used to characterize the ligand and zinc complex. By measuring the molar conductance, the non-electrolytic character of the complex was confirmed. The zinc ion is coordinated in a pentadentate manner, according to an IR and NMR investigation. Viscosity measurements, absorption and fluorescence spectroscopy were utilized to examine the complex's interaction with CT (calf thymus) DNA. Furthermore, the ligand and complex's ADMET characteristics were ascertained through the use of ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) study. Calculation of the different electronic parameters of the optimized structure through Density Functional Theory (DFT) indicated the stability of the Zn(II) complex. Molecular docking study reflected the future opportunity for the consideration of Zn(II) complex to fight against Alzheimer and Glaucoma diseases.

Environmentally benign synthesis of unsymmetrical ureas and their evaluation as potential HIV-1 protease inhibitors via a computational approach

The present work reports the cost-effective, high yielding and environmentally acceptable preparation of unsymmetrical ureas from thiocarbamate salts using sodium percarbonate as an oxidant. Efficacy of the unsymmetrical ureas as potential human immune deficiency virus (HIV-1) protease inhibitors has been evaluated via in silico approach. The results revealed interactions of the urea compounds at the active site of the enzyme with favorable binding affinities causing possible mutations hindering the functioning of the enzyme. Further computational assessment of IC50 using known references satisfactorily authenticated the inhibitory action of the selected compounds against HIV-1 protease. Added to the easy synthesis of the ureas following an environmentally benign protocol, this work may be a valuable addition to the ongoing search for drugs with better efficacy profiles and reduced toxicity against HIV.

Probing analysis of Cu-doping on the structural, optical, morphological and magnetic properties of hematite nanoparticles and their antibacterial activity

The present study describes the synthesis of pure and Cu doped α-Fe2O3nanoparticles (with various concentrations of Copper 1, 3, 6, and 9 wt%) by conventional chemical precipitation technique and examines their structural, morphological, optical, magnetic, and antibacterial capabilities. The XRD pattern of pure and Cu-doped α-Fe2O3 nanoparticles exhibit rhombohedral structure and the estimated crystalline sizes were ranged from 39 to 58 nm. It is discovered that the estimated density dislocations linked to the agglomeration/cluster formations diminish when interstitial vacancies are filled with copper. The obtained bandgap from Tauc's plot, 2.07 eV of pure α-Fe2O3 is found to less than Cu doped α-Fe2O3 nanoparticles (2.9-3.4 eV), due to the structural changes and the tailing of localised states into deep bandgap energy levels. The intense blue emission bands (410-490 nm) arised due to the movement of trapped electrons from the donor level to the valance band and broad green emission bands (522-560 nm) are due to deep level CuO defect to the Fe2O3. The fundamental stretching of Fe-O vibrations and the presence of Cu in prepared samples were identified in FTIR and Raman spectra. SEM micrograph shows the uniform distribution of spherical nanoparticles with size ranged from 39 to 61 nm, which is in good accord with XRD studies. Further, the magnetic characteristics of the pure and Cu-doped α-Fe2O3 samples were assessed using a vibrating sample magnetometer (VSM); the ensuing hysteresis loop of the Cu-doped α-Fe2O3 displays weaker ferromagnetic behaviour. In the present investigations, the disc diffusion technique has been used to examine the antibacterial activity. Thus, the results of antibacterial activities demonstrated that at concentrations of 200 and 500 μg/ml of pure and Cu-doped α-Fe2O3 NPs, the highest zone of inhibition was found against gram (+ve) positive bacteria and was followed by the gram (-ve) negative bacteria's.

Synthesis, characterization, DNA binding interactions, DFT calculations, and Covid-19 molecular docking of novel bioactive copper(I) complexes developed via unexpected reduction of azo-hydrazo ligands

In this work, we focused on the 3rd goal of the sustainable development plan: achieving good health and supporting well-being. Two redox-active hydrazo ligands namely, phenylcarbonohydrazonoyldicyanide (PCHD) and pyridin-4-ylcarbonohydrazonoyl-dicyanide (PyCHD), and their copper(I) complexes have been synthesized and characterized. The analytical data indicates the formation of copper(I) complexes despite starting with copper(II) perchlorate salt. The 1H-NMR and UV-visible spectral studies in DMSO revealed that PyCHD mainly exists in its azo-form, while PCHD exists in azo ↔ hydrazo equilibrium form, and confirmed the copper(I) oxidation state. XPS, spectral and electrochemistry data indicated the existence of copper(I) valence of both complexes. Cyclic voltammetry of PCHD and its copper(I) complex supported the reduction power of the ligand. The antimicrobial activity, cytotoxicity against the mammalian breast carcinoma cell line (MCF7), and DNA interaction of the compounds are investigated. All compounds showed high antimicrobial, and cytotoxic activities, relative to the standard drugs. Upon studying the wheat DNA binding, PCHD and PyCHD were found to bind through external contacts, while both [Cu(PCHD)2]ClO4.H2O and [Cu(PyCHD)2]ClO4.H2O were intercalated binding. In-silico molecular docking simulations against Estrogen Receptor Alpha Ligand Binding Domain (ID: 6CBZ) were performed on all produced compounds and confirmed the invitro experimentally best anticancer activity of [Cu(PyCHD)2]ClO4.H2O. The molecular docking tests against SARS-CoV-2 main protease (ID: 6 WTT) showed promising activity in the order of total binding energy values: [Cu(PCHD)2]ClO4.H2O > [Cu(PyCHD)2]ClO4.H2O > PCHD > PyCHD.

Experimental and theoretical approaches to interactions between DNA and purine metabolism products

Deoxyribonucleic acid (DNA) is a significant target for small organic and inorganic drug molecules. Understanding the DNA interaction mechanism of these molecules is vital for new drug designs. In this work, interactions between xanthine (XT), theophylline (TP), and theobromine (TB) with calf-thymus double-strained DNA (dsDNA) were monitored via an experimental and theoretical approach. Experimentally, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were used on the surface of the NiO/MWCNT/NNaM/PGE electrochemical platform in vitro. Kinetic parameters, including diffusion coefficients, surface concentrations, and standard heterogeneous rate constants, were measured in the absence and presence of DNA using scan rate studies. In the presence of DNA, kinetic parameters were observed to be reduced significantly. Thermodynamic parameters, such as DNA binding constants and standard free Gibbs energies, were calculated for each molecule using the CV and DPV techniques. Both techniques suggested a binding affinity order of XT > TB > TP. Theoretically, density functional theory was applied for geometry optimization, natural bond orbital analyses, and molecular orbital energies of XT, TP, and TB. Experimental and theoretical binding affinities confirm each other. The most energetically stable ligand-DNA complexes expressed that XT, TP, and TB interact with dsDNA via minor groove binding mode, using mostly hydrogen bonds.

Anticancer Behavior of Pyrrolidine-Based Palladium(II) Complexes and Biophysical Approach on Their DNA, BSA Binding Activity, Molecular Docking, and DFT Study

A series of pyrrolidine-based Pd(II) complexes, [Pd(AEP)Cl2] (C-1), [Pd(AEP)(OH2)2]2+(C-2), [Pd(AEP)(L-cys)]+ (C-3), [Pd(AEP)(N-ac-L-cys)] (C-4), [Pd(AEP)(GSH)] (C-5), and [Pd(AEP)(DL-meth)]2+ (C-6) (where, AEP = 1-(2-aminoethyl)pyrrolidine, L-cys = l-cysteine, N-ac-L-cys = N-acetyl-l-cysteine, GSH = glutathione, and DL-meth = dl-methionine), as anticancer drug candidates have been synthesized and characterized. The DNA binding property of the complexes was executed by gel electrophoresis and spectrophotometric and viscometric methods, and their interaction with BSA was also investigated by various spectroscopic methodologies. The binding activity of the Pd(II) complexes with DNA and BSA were assessed to evaluate their binding mode and binding constants. Molecular docking was performed to correlate with the experimental results on the interaction of the complexes with DNA and BSA. The changes in the microenvironmental and structural properties of BSA are monitored by a synchronous and 3D fluorescence study. The structural properties were evaluated by DFT and TD-DFT studies. The anticarcinogenic activity of the Pd(II) complexes was assessed by PASS prediction software to corroborate with the experimental results of the anticancer activity of the complexes. The ROS generation in cancer cell lines has been investigated, and the cell death mechanism through apoptosis was confirmed by measuring the protein expression. All these complexes have excellent anticancer activity compared to ancillary ligands. The cancer cell line (HCT116) shows almost similar or better cell inhibition activity when treated with the Pd(II) complexes compared to cisplatin, whereas the adverse effect is minimum on a normal cell (NKE). Both the Pd(II) and Pt(II) complexes carrying the same ligands reveal almost similar antiproliferative activity.

Computational studies indicated the effectiveness of human metabolites against SARS-Cov-2 main protease

To fight against the devastating coronavirus disease 2019 (COVID-19), identifying robust anti-SARS-CoV-2 therapeutics from all possible directions is necessary. To contribute to this effort, we selected a human metabolites database containing waters and lipid-soluble metabolites to screen against the 3-chymotrypsin-like proteases (3CLpro) protein of SARS-CoV-2. The top 8 hits from virtual screening displayed a docking score varying between ~ - 11 and ~ - 14 kcal/mol. Molecular dynamics simulations complement the virtual screening study in conjunction with the molecular mechanics generalized Born surface area (MM/GBSA) scheme. Our analyses revealed that (HMDB0132640) has the best glide docking score, - 14.06 kcal/mol, and MM-GBSA binding free energy, - 18.08 kcal/mol. The other three lead molecules are also selected along with the top molecule through a critical inspection of their pharmacokinetic properties. HMDB0132640 displayed a better binding affinity than the other three compounds (HMDB0127868, HMDB0134119, and HMDB0125821) due to increased favorable contributions from the intermolecular electrostatic and van der Waals interactions. Further, we have investigated the ligand-induced structural dynamics of the main protease. Overall, we have identified new compounds that can serve as potential leads for developing novel antiviral drugs against SARS-CoV-2 and elucidated molecular mechanisms of their binding to the main protease. Identification of probable hits from human metabolites against SARS-CoV-2 using integrated computational approaches-Missed against MS.

Syntheses, in vitro, and in silico studies of rhodanine-based schiff bases as potential α-amylase inhibitors and radicals (DPPH and ABTS) scavengers

A two-step reaction method was used to synthesize a series of rhodanine-based Schiff bases (2-33) that were characterized using spectroscopic techniques. All compounds were assessed for α-amylase inhibitory and radical scavenging (DPPH and ABTS) activities. In comparison to the standard acarbose (IC50 = 9.08 ± 0.07 µM), all compounds demonstrated good to moderate α-amylase inhibitory activity (IC50 = 10.91 ± 0.08-61.89 ± 0.102 µM). Compounds also demonstrated significantly higher DPPH (IC50 = 10.33 ± 0.02-96.65 ± 0.03 µM) and ABTS (IC50 = 12.01 ± 0.12-97.47 ± 0.13 µM) radical scavenging activities than ascorbic acid (DPPH, IC50 = 15.08 ± 0.03 µM; ABTS, IC50 = 16.09 ± 0.17 µM). The limited structure-activity relationship (SAR) suggests that the position and nature of the substituted groups on the phenyl ring have a vital role in varying inhibitory potential. Among the series, compounds with an electron-withdrawing group at the para position showed the highest potency. Kinetic studies revealed that the compounds followed a competitive mode of inhibition. Molecular docking results are found to agree with experimental findings, showing that compounds reside in the active pocket due to the main rhodanine moiety.

Recent Overview of Potent Antioxidant Activity of Coordination Compounds

During recent decades, the complexation of organic ligands toward several metal ions of s-p and d-block has been applied as a plan to enhance its antioxidant performance. Due to their wide range of beneficial impacts, coordination compounds are widely used in industries, specifically in the medicinal and pharmaceutical fields. The activity is generally improved by chelation consequently knowing that the characteristics of both ligands and metals can lead to the development of greatly active compounds. Chelation compounds are a substitute for using the traditional synthetic antioxidants, because metal chelates present benefits, including a variety in geometry, oxidation states, and coordination number, that assist and favor the redox methods associated with antioxidant action. As well as understanding the best studied anti-oxidative assets of these compounds, coordination compounds are involved in the free radical scavenging process and protecting human organisms from the opposing effects of these radicals. The antioxidant ability can be assessed by various interrelated systems. The methodological modification offers the most knowledge on the antioxidant property of metal chelates. Colorimetric techniques are the most used, though electron paramagnetic resonance (EPR) is an alternative for metallic compounds, since color does not affect the results. Information about systems, with their benefits, and restrictions, permits a dependable valuation of the antioxidant performance of coordination compounds, as well as assisting application in various states wherever antioxidant drugs are required, such as in food protection, appropriate good-packaged foods, dietary supplements, and others. Because of the new exhaustive analysis of organic ligands, it has become a separate field of research in chemistry. The present investigation will be respected for providing a foundation for the antioxidant properties of organic ligands, future tests on organic ligands, and building high-quality antioxidative compounds.

Study of Interactions Between 3-benzoyl-4-hydroxy-2-methyl-2H-1, 2-benzothiazine and Human DNA by Theoretical, Spectroscopic and Viscometric measurements

From the last few years mode of interactions between drugs and DNA is an attractive research area as it bridges chemistry, molecular biology and medicinal science. Interactions between small heterocyclic molecules and human DNA is a noteworthy feature in pharmacology for investigation of drugs mechanism and designing of more effective and target specific drugs with fewer side effects. The present research work focuses on the theoretical investigations of 3-benzoyl-4-hydroxy-2-methyl-2H-1, 2-benzothiazine (SASA) by using Gaussian (16 W) software to predict optimized geometry, HOMO-LUMO gap, bond length, bond angle, dihedral angle, electronic and vibrational spectra. Possible reaction site observed in SASA was C_7, C₉ and C₁₈ as these atoms show maximum charge density. Later the interactions of SASA with human DNA was explored spectroscopic investigations and viscometric investigations at physiological buffers of pH of 4.7 (stomach pH) and 7.4 (blood pH) respectively. Maximum absorbance between SASA-DNA complex was observed in buffer solution of pH 3.4 at wavelength of 370 nm, whereas at 7.4 has maximim absorbance between. Spectroscopic results reflects the bathochromic and hyperchromic shift succeeding the addition of human DNA. During viscosity measurement, intercalation and electrostatic mode of interaction were detected at low and high concentration of drug in solution respectively. Increase in the value of rate constant was observed with the increase in concentration of drug. Larger values of rate constant were observed at pH 7.4 in comparison to pH 3.5. Rate constant, thermodynamic parameters and viscometric analysis prefers the intake of SASA via blood.

Development of New Azomethine Metal Chelates Derived from Isatin: DFT and Pharmaceutical Studies

Through the condensation of isatin (indoline-2, 3-dione) and aniline in a 1:1 ratio, a Schiff base ligand was synthesized and characterized via (¹H-NMR, mass, IR, UV-Vis) spectra. Elemental analyses, spectroscopy (¹H-NMR, mass, UV-Vis), magnetic susceptibility, molar conductivity, mass spectra, scanning electron microscope (SEM), and thermal analysis have all been used to characterize a series of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) metal complexes derived from the titled ligand. The metal-to-ligand ratio is 1:1, according to the analytical data. The Schiff base ligand displayed bidentate behavior with NO coordination sites when it bonded to metal ions, as seen by the IR spectra. The magnetic moment measurement and UV-Vis spectral investigation showed the octahedral geometry of the Cr(III), Fe(III), Co(II), Ni(II), and Zn(II) complexes, whereas they suggested the tetrahedral geometry of the Mn(II), Cu(II), and Cd(II) complexes. The thermal analysis study confirmed the presence of both hydrated and coordinated water molecules in all the compounds, except for the Mn(II) complex, and showed that the complexes decomposed in three or five decomposition steps leaving the corresponding metal oxide as a residue. The ligand and its metal complexes' antibacterial efficacy were evaluated. The findings showed that the metal complexes had stronger antibacterial properties than the ligand alone. The ligand and its metal complexes' anticancer properties were also investigated. A DFT investigation is also reported to gather information regarding the electronic features of the ligand and its metal complexes. Finally, drug-likeness and ADME characteristics were also calculated as parameters.

Metal Complexes with Schiff Bases: Data Collection and Recent Studies on Biological Activities

Metal complexes play a crucial role in pharmaceutical sciences owing to their wide and significant activities. Schiff bases (SBs) are multifaceted pharmacophores capable of forming chelating complexes with various metals in different oxidation states. Complexes with SBs are extensively studied for their numerous advantages, including low cost and simple synthetic strategies. They have been reported to possess a variety of biological activities, including antimicrobial, anticancer, antioxidant, antimalarial, analgesic, antiviral, antipyretic, and antidiabetic ones. This review summarizes the most recent studies on the antimicrobial and antiproliferative activities of SBs-metal complexes. Moreover, recent studies regarding mononuclear and binuclear complexes with SBs are described, including antioxidant, antidiabetic, antimalarial, antileishmanial, anti-Alzheimer, and catecholase activities.

DNA Binding and Anticancer Properties of New Pd(II)-Phosphorus Schiff Base Metal Complexes

DNA has become the target of metal complexes in cancer drug discovery. Due to the side effects of widely known cisplatin and its derivative compounds, alternative metal-based drug discovery studies are still ongoing. In this study, the DNA-binding ability of Pd(II) and Pt(II) complexes of four phosphorus Schiff base ligands and four hydrazonoic-phosphines are investigated by using in silico analyses. Phosphorus Schiff base-Pd(II) complexes encoded as B1 and B2 with the best DNA-binding potential are synthesized and characterized. The DNA-binding potentials of these two new Pd(II) complexes are also investigated experimentally, and their antitumor properties are demonstrated in vitro in A549, MCF7, HuH7, and HCT116 cancer cells. The mechanisms of these metal complexes that kill the cells mentioned above in different activities are elucidated by flow cytometry apoptosis analysis and colony formation analysis The in silico binding energies of these two new palladium complexes ΔG (B1): −4.51 and ΔG (B2): −6.04 kcal/mol, and their experimental DNA-binding constants were found as Kb (B1): 4.24 × 10⁵, Kb (B2): 4.98 × 10⁵). The new complexes, which show different antitumor effects in different cells, are the least effective in HuH7 liver cells, while they showed the best antitumor properties in HCT116 colon cancer cells.

Pincer Complexes Derived from Tridentate Schiff Bases for Their Use as Antimicrobial Metallopharmaceuticals

Within the current challenges in medicinal chemistry, the development of new and better therapeutic agents effective against infectious diseases produced by bacteria, fungi, viruses, and parasites stands out. With chemotherapy as one of the main strategies against these diseases focusing on the administration of organic and inorganic drugs, the latter is generally based on the synergistic effect produced by the formation of metal complexes with biologically active organic compounds. In this sense, Schiff bases (SBs) represent and ideal ligand scaffold since they have demonstrated a broad spectrum of antitumor, antiviral, antimicrobial, and anti-inflammatory activities, among others. In addition, SBs are synthesized in an easy manner from one-step condensation reactions, being thus suitable for facile structural modifications, having the imine group as a coordination point found in most of their metal complexes, and promoting chelation when other donor atoms are three, four, or five bonds apart. However, despite the wide variety of metal complexes found in the literature using this type of ligands, only a handful of them include on their structures tridentate SBs ligands and their biological evaluation has been explored. Hence, this review summarizes the most important antimicrobial activity results reported this far for pincer-type complexes (main group and d-block) derived from SBs tridentate ligands.

Innovation of Imine Metal Chelates as Corrosion Inhibitors at Different Media: A Collective Study

The corrosion inhibition of transition metal chelates derived from Schiff base ligands was tested for (mild, copper, stainless, aluminum and carbon) steel in various concentrations of (HCl, HNO3 and H2SO4) acidic medium at 25 °C through (weight loss, potentiodynamic polarization, polarization curves, electrochemical impedance spectroscopy (EIS) and open circuit potential measurements (OCP)) techniques. The studied compounds were identified with various spectral, analytical and physico-chemical techniques. It was observed that the investigated compounds had a significant inhibitory impact on the corrosion of diverse steels in the medium investigated. The analysis shows that increasing the dose of the studied complexes improves the corresponding inhibitory efficiency values. Negative results of Gibb's free adsorption energy (ΔGads0) prove the suppression process's spontaneous and physical adsorption, which contradicts the Langmuir adsorption isotherm. As a result of this insight, a novel bridge between nuclearity driven coordinated inorganic chemistry and materials, as well as corrosion control, has been built. This review provides an overview of the use of Schiff bases and associated transition metals as potential corrosion inhibitors, including the factors that influence their application.

Cytotoxic effects of Pd(II) complexes on cancer and normal cells: Their DNA & BSA adduct formation and theoretical approaches

Herein, we report the synthesis and characterisation of a series of Pd(II) complexes: Pd(TEEDA)Cl₂, C-1; [Pd(TEEDA)(OH₂)₂](NO₃)₂, C-2; [Pd(TEEDA)(l-cys)](NO₃)₂, C-3; [Pd(TEEDA)(NALC)], C-4; [Pd(TEEDA)(Meth)](NO₃)₂, C-5; and [Pd(TEEDA)(GSH)], C-6 (where TEEDA = N,N,N'-Triethylenediamine, l-cys = l-cysteine, NALC = N-acetyl-l-cysteine, Meth = dl-methionine and GSH = glutathione). UV-Vis spectroscopic characterisation was supported by TD-DFT theoretical simulation using Gaussian09 software. Different reactivity parameters were calculated from the energy difference between HOMO and LUMO of the complexes by DFT. The bonding mode of the labile ligands was confirmed by NBO analysis. Interaction of the complexes with DNA has been observed by gel electrophoresis experiment. DNA binding nature as well as binding constants of the complexes were measured with UV-Vis and fluorescence spectroscopic method. The binding nature of the complexes with DNA was confirmed by viscometric titration. Interaction of the complexes with BSA was investigated by UV-Vis and fluorescence titration method. Cytotoxic activity of the Pd(II) complexes was evaluated on A549 (lung carcinoma epithelial cells), HCT116(Colorectal Carcinoma) and HEK293 (Human embryonic kidney cells) cell lines. The ROS generation in the presence of the complexes was tested both on cancer cell lines A549 and HCT116 as well as human normal cell HEK293.

Development of Metal Complexes for Treatment of Coronaviruses

Coronavirus disease (SARS-CoV-2) is a global epidemic. This pandemic, which has been linked to high rates of death, has forced some countries throughout the world to implement complete lockdowns in order to contain the spread of infection. Because of the advent of new coronavirus variants, it is critical to find effective treatments and vaccines to prevent the virus's rapid spread over the world. In this regard, metal complexes have attained immense interest as antibody modifiers and antiviral therapies, and they have a lot of promise towards SARS-CoV-2 and their suggested mechanisms of action are discussed, i.e., a new series of metal complexes' medicinal vital role in treatment of specific proteins or SARS-CoV-2 are described. The structures of the obtained metal complexes were fully elucidated by different analytical and spectroscopic techniques also. Molecular docking and pharmacophore studies presented that most of complexes studied influenced good binding affinity to the main protease SARS-CoV-2, which also was attained as from the RCSB pdb (Protein Data Bank) data PDB ID: 6 W41, to expect the action of metal complexes in contradiction of COVID-19. Experimental research is required to determine the pharmacokinetics of most of the complexes analyzed for the treatment of SARS-CoV-2-related disease. Finally, the toxicity of a metal-containing inorganic complex will thus be discussed by its capability to transfer metals which may bind with targeted site.

Antimicrobial Activities Along With Spectrophotometric Assessment of Stability Constants of Copper (II) and Cobalt (II) With 1,2-Bis(2,5-dimethoxybenzylidene) Hydrazine

The stability constants of 1,2-bis(2,5-dimethoxybenzylidene) hydrazine (DMBH) were determined using the modified Job’s method with the addition of the UV-Vis approach using salts of copper (II) (chloride and acetate) and salts of cobalt (II) (chloride and nitrate). Copper (II) chloride with a ligand at 1L:2M (stoichiometric ratio) was discovered to have a higher stability constant log value (6.995) than other metal salts. The stability constant log value (5.811) for cobalt (II) nitrate at 1L:2M (stoichiometric ratio) was found to be less stable than the other stability constants evaluated. Antimicrobial properties of the ligand were tested against Entamoeba coli, Candida albicans, and Staphylococcus aureus. The ligand was found to be effective against these strains, with positive results.

Fabrication, DFT Calculation, and Molecular Docking of Two Fe(III) Imine Chelates as Anti-COVID-19 and Pharmaceutical Drug Candidate

Two tetradentate dibasic chelating Schiff base iron (III) chelates were prepared from the reaction of 2,2′-((1E,1′E)-(1,2-phenylenebis(azanylylidene))bis(methanylylidene))bis(4-bromophenol) (PDBS) and 2,2′-((1E,1′E)-((4-chloro-1,2-phenylene)bis(azanylylidene))-bis(methanylylidene))bis(4-bromophenol) (CPBS) with Fe³⁺ ions. The prepared complexes were fully characterized with spectral and physicochemical tools such as IR, NMR, CHN analysis, TGA, UV-visible spectra, and magnetic moment measurements. Moreover, geometry optimizations for the synthesized ligands and complexes were conducted using the Gaussian09 program through the DFT approach, to find the best structures and key parameters. The prepared compounds were tested as antimicrobial agents against selected strains of bacteria and fungi. The results suggests that the CPBSFe complex has the highest activity, which is close to the reference. An MTT assay was used to screen the newly synthesized compounds against a variety of cell lines, including colon cancer cells, hepatic cellular carcinoma cells, and breast carcinoma cells. The results are expressed by IC50 value, in which the 48 µg/mL value of the CPBSFe complex indicates its success as a potential anticancer agent. The antioxidant behavior of the two imine chelates was studied by DPPH assay. All the tested imine complexes show potent antioxidant activity compared to the standard Vitamin C. Furthermore, the in vitro assay and the mechanism of binding and interaction efficiency of the tested samples with the receptor of COVID-19 core protease viral protein (PDB ID: 6lu7) and the receptor of Gram-negative bacteria (Escherichia coli, PDB ID: 1fj4) were investigated using molecular docking experiments.

Photodegradation of Azathioprine in the Presence of Sodium Thiosulfate

The effect of sodium thiosulfate (ST) on the photodegradation of azathioprine (AZA) was analyzed by UV-VIS spectroscopy, photoluminescence (PL), FTIR spectroscopy, Raman scattering, X-ray photoelectron (XPS) spectroscopy, thermogravimetry (TG) and mass spectrometry (MS). The PL studies highlighted that as the ST concentration increased from 25 wt.% to 75 wt.% in the AZA:ST mixture, the emission band of AZA gradual downshifted to 553, 542 and 530 nm. The photodegradation process of AZA:ST induced: (i) the emergence of a new band in the 320–400 nm range in the UV-VIS spectra of AZA and (ii) a change in the intensity ratio of the photoluminescence excitation (PLE) bands in the 280–335 and 335–430 nm spectral ranges. These changes suggest the emergence of new compounds during the photo-oxidation reaction of AZA with ST. The invoked photodegradation compounds were confirmed by studies of the Raman scattering, the FTIR spectroscopy and XPS spectroscopy through: (i) the downshift of the IR band of AZA from 1336 cm⁻¹ to 1331 cm⁻¹, attributed to N-C-N deformation in the purine ring; (ii) the change in the intensity ratio of the Raman lines peaking at 1305 cm⁻¹ and 1330 cm⁻¹ from 3.45 to 4.57, as the weight of ST in the AZA:ST mixture mass increased; and (iii) the emergence of a new band in the XPS O1s spectrum peaking at 531 eV, which was associated with the C=O bond. Through correlated studies of TG-MS, the main key fragments of ST-reacted AZA are reported.