Synthesis, structure, and in vitro biological studies of benzothiazole based Schiff base ligand and its binary and ternary Co(III) and Ni(II) complexes

Exploring the enzyme inhibitor potential and therapeutic applications of transition metal complexes of Methoxy-Schiff Base via triangular investigation

Transition metal(II) complexes of (E)-7-methoxy-N-(4-methoxybenzylidene)benzo[d]- thiazole-2-amine Schiff base ligand have been created using benzothiazole derivative. These compounds were characterized by means of conventional spectroscopic and analytical techniques. Furthermore, computational investigations with SWISS ADMET, Density Functional Theory, and molecular docking, authorized the biological efficacy of the complexes. The 3v03 bovine serum albumin protein was also subjected to a molecular docking study. The docking scores and interacting amino acids have been analyzed which reveal that the synthesized compounds interact potently with the protein enzyme. All the metal complexes have a great propensity to attach to Calf Thymus Deoxyribo Nucleic Acid via the intercalation process. The anticancer activity of the synthesized compounds, assessed in vitro using four human cancer cell lines, reveals that Cu(II) complex exhibits the highest activity (lowest IC50 values) against HeLa and MCF-7 cancer cell lines. Compared to the reference cisplatin, all of the complexes exhibit higher IC50 values. Screening assays both in vitro and in vivo corroborate that the complexes exhibit greater activity than the free Schiff base.

Chemistry of 2-(2'-Aminophenyl)benzothiazole Derivatives: Syntheses, Photophysical Properties and Applications

2-(2'-aminophenyl)benzothiazole is a readily tunable fluorescent core with widespread applications in coordination chemistry, sensing, light-emitting processes, medicinal chemistry, and catalysis. This review provides an overview of the synthetic methodologies to access 2-(2'-aminophenyl)benzothiazole and its organic derivatives, including various phosphorous and silane pincer ligands. The luminescent properties will be discussed, with a special focus on ESIPT and AIE processes. The coordination of transition metals and lanthanides is presented, as well as their influence on biological and light-emitting properties. 2-(2'-aminophenyl)benzothiazole derivatives have also been employed as sensors for a range of cations and anions due to their various binding modes, as well as for bioimaging purposes. Recently, the first application in photocatalysis has emerged, showing one of the many openings for these organic building blocks in the future.

DNA Binding, Molecular Docking and Antimicrobial Studies of Co(III) Polypyridyl Complexes

Three new cobalt(III) polypyridyl complexes [Co(phen)2(TIPB)]3+(1) {TIPB = 5-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)thiophene-2-yl-2-boronic acid}, (phen = 1,10-Phenanthroline), [Co(bpy)2(TIPB)]3+(2) (bpy = 2,2'bipyridyl), [Co(dmb)2(TIPB)]3+(3) (dmb = 4, 4'-dimethyl 2, 2'-bipyridine) have been synthesized and characterized by spectral studies FTIR, UV-vis, 1H, 13C-NMR, Mass Spectroscopy and Elemental analysis. The binding properties of all three complexes towards calf-thymus DNA (CT-DNA) have been investigated using UV-visible, emission spectroscopy and viscosity measurements, indicating that all the complexes bind to CT-DNA predominantly through intercalation, but with different affinities. The binding strength of these complexes were 1 > 2 > 3. These complexes cleaved the pBR322 DNA into different forms when irradiated under UV light. The binding studies of Co(III) polypyridyl complexes with ds-DNA were carried out by molecular modeling (MM) studies to identify the binding interactions. The molecular mechanics studies were performed on metal complexes to obtain stable 3D conformers. Double-stranded DNA was docked to metal complexes' energy-minimized three-dimensional structures. Through intercalation, the aromatic ligand TIPB makes it easier for the metal complex to bind to DNA. The necessary characteristics for metal complexes to be regarded as DNA intercalators are their substantial interactions with DNA. The available experimental data provides strong support for the molecular docking data. The binding selectivity and strength of the metal complex with DNA show that the preferred binding mode involves guanine rich site. It reveals that complexes will bind in between base pairs of DNA and gives information about the binding residues and strength. The antimicrobial studies of these complexes give considerable activity with different bacteria like Staphylococcus aureus, and Bacillus subtilis.

Visible-Light Organic Photosensitizers Based on 2-(2-Aminophenyl)benzothiazoles for Photocycloaddition Reactions

We have studied 2-(2-aminophenyl)benzothiazole and related derivatives for their photophysical properties in view of employing them as new and readily tunable organic photocatalysts. Their triplet energies were estimated by DFT calculations to be in the range of 52-57 kcal mol-1, suggesting their suitability for the [2+2] photocycloaddition of unsaturated acyl imidazoles with styrene derivatives. Experimental studies have shown that 2-(2-aminophenyl)benzothiazoles comprising alkylamino groups (NHMe, NHiPr) or the native amino group provide the best photocatalytic results in these visible-light mediated [2+2] reactions without the need of any additives, yielding a range of cyclobutane derivatives. A combined experimental and theoretical approach has provided insights into the underlying triplet-triplet energy transfer process.

Bidentate bromhexine drug coordination modes with various transition metal ions: Synthesis, characterization, and in vitro antibacterial and anti-breast cancer activity tests

BACKGROUND

Bromhexine (BHX) is a mucolytic drug used in treatment the respiratory disorders which are associated with excessive or viscid mucus. Transition metal complexes have made tremendous progress in the treatment of a variety of human ailments, according to reported articles. Transition metal complexes are being developed as medications with a lot of effort. Metal complexes can form a variety of coordination geometries, giving them distinct forms. So, binary metal complexes of bromhexine drug have been prepared to enhance the biological activity and stability of the free drug.

METHODS

A new series of binary complexes with bromhexine drug (BHX) has been prepared with some transition metal ions namely Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II). Elemental analyses, FT-IR, mass spectrometry, thermal studies and UV-Vis spectra have been used to characterize and structurally elucidate the produced metal complexes. Antibacterial activity has been tested for the ligand and metal complexes against a variety of pathogenic bacterial species (Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus). In addition, the ligand has been tested for anticancer efficacy against the MCF-7 breast cancer cell line, as opposed to binary metal complexes. The binding orientation or conformation of the free BHX ligand and Co(II) complex in the active region of the protein of crystal structure of Escherichia coli (PDB ID: 3T88) and Pseudomonas aeruginosa (PDB ID: 6NE0) has been performed using molecular docking studies.

RESULTS

The BHX ligand coupled in neutral bidentate mode to the metal ions, according to FT-IR and 1H-NMR spectral results. The molar conductivity measurements of the complexes in DMF proved the electrolytic nature of all binary complexes. Co(II) complex showed the highest inhibition zone diameter against S. aureus, E. coli and P. aeruginosa. Zn(II) complex had the greatest inhibitory effect against P. aeruginosa and B. subtilis. Also, Cd(II) chelate appeared high efficacy as antibacterial agent against Pseudomonas aeruginosa and Staphylococcus aureus.

CONCLUSION

All the output data conjugated to confirm the octahedral geometry of the metal complexes. The biological findings revealed that metal complexes can be more active than the free BHX ligand. Against MCF-7 cell line, Cd(II)-L complex is highly active complex (4.95 µg/mL) but BHX free drug is the most active compound (3.96 µg/mL).

Cytotoxic Cu(II) Complexes with a Novel Quinoline Derivative Ligand: Synthesis, Molecular Docking, and Biological Activity Analysis

The utilization of metallodrugs as a viable alternative to organic molecules has gained significant attention in modern medicine. We hereby report synthesis of new imine quinoline ligand (IQL)-based Cu(II) complexes and evaluation of their potential biological applications. Syntheses of the ligand and complexes were achieved by condensation of 7-chloro-2-hydroxyquinoline-3-carbaldehyde and 2,2'-thiodianiline, followed by complexation with Cu(II) metal ions. The synthesized ligand and complexes were characterized using UV-vis spectroscopy, TGA/DTA, FTIR spectroscopy, 1H and 13C NMR spectroscopy, and pXRD. The pXRD diffractogram analysis revealed that the synthesized ligand and its complexes were polycrystalline systems, with nanolevel average crystallite sizes of 13.28, 31.47, and 11.57 nm for IQL, CuL, and CuL 2 , respectively. The molar conductivity confirmed the nonelectrolyte nature of the Cu(II) complexes. The biological activity of the synthesized ligand and its Cu(II) complexes was evaluated with in vitro assays, to examine anticancer activity against the MCF-7 human breast cancer cell line and antibacterial activity against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacterial strains. The CuL complex had the highest cytotoxic potency against MCF-7 breast cancer cells, with an IC50 of 43.82 ± 2.351 μg/mL. At 100 μg/mL, CuL induced the largest reduction of cancer cell proliferation by 97%, whereas IQL reduced cell proliferation by 53% and CuL 2 by 28%. The minimum inhibitory concentration for CuL was found to be 12.5 μg/mL against the three tested pathogens. Evaluation of antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl revealed that CuL exhibited the highest antioxidant activity with IC50 of 153.3 ± 1.02 μg/mL. Molecular docking results showed strong binding affinities of CuL to active sites of S. aureus, E. coli, and estrogen receptor alpha, indicating its high biological activity compared to IQL and CuL 2 .