Synthesis, characterization and antimicrobial activity of a bidentate NS Schiff base containing S-allyl dithiocarbazate and its complexes

Dithiocarbazate ligands and their Ni(II) complexes with potential biological activity: Structural, antitumor and molecular docking study

In the search for new metal complexes with antitumor potential, two dithiocarbazate ligands derived from 1,1,1-trifluoro-2,4-pentanedione (H2L1) and (H2L2) and four Ni(II) complexes, [Ni(L1)PPh3] (1), [Ni(L1)Py] (2), [Ni(L2)PPh3] (3), and [Ni(L2)Py] (4), were successfully synthesized and investigated by physical-chemistry and spectroscopic methods. The crystal structure of the H2L1 and the Ni(II) complexes has been elucidated by single-crystal X-ray diffraction. The obtained structure from H2L1 confirms the cyclization reaction and formation of the pyrazoline derivative. The results showed square planar geometry to the metal centers, in which dithiocarbazates coordinated by the ONS donor system and a triphenylphosphine or pyridine molecule complete the coordination sphere. Hirshfeld surface analysis by dnorm function was investigated and showed π–π stacking interactions upon the molecular packing of H2L1 and non-classical hydrogen bonds for all compounds. Fingerprint plots showed the main interactions attributed to H⋅H C⋅H, O⋅H, Br⋅H, and F⋅H, with contacts contributing between 1.9% and 38.2%. The mass spectrometry data indicated the presence of molecular ions [M + H]+ and characteristic fragmentations of the compounds, which indicated the same behavior of the compounds in solution and solid state. Molecular docking simulations were studied to evaluate the properties and interactions of the free dithiocarbazates and their Ni(II) complexes with selected proteins and DNA. These results were supported by in vitro cytotoxicity assays against four cancer cell lines, showing that the synthesized metal complexes display promising biological activity.

Enhancing the biological properties of zinc complexes with bis(indolyl)methane groups: Synthesis, characterization, DNA interaction, and biocide activity

The unprecedented mononucleated ligand (6,6-di(1H-indol-3-yl)-N,N-bis(pyridin-2-ylmethyl)hexan-1-amine (L^C5) with an N₃-donor set and its complexes [Zn(L^C5)Cl₂] • 2CH₃OH (1) and [Zn(L^C5)₂](ClO₄)₂ (2), were successfully prepared. All compounds were fully characterized by a suite of physicochemical methods. Fluid ¹H and ¹³C NMR spectroscopy, as well as DFT and TD-DFT calculations, were carried out to propose a viable structural arrangement for both complexes. The interaction between these compounds and DNA was monitored in the UV region where binding constants (K_b) were estimated (2 > 1 > L^C5). These data were corroborated by DNA cleavage assays using groove binders, circular dichroism, and docking studies. Both complexes confirmed their biocide activity against selected microorganisms: Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria, the filamentous fungi A. fumigatus and S. cerevisiae. Finally, the cytotoxic activities of 1 and 2 were tested against the erythroleukemia K562 cell line. For all biological studies, it was probed that the presence of the indole moieties and the zinc atoms in the chemical composition of the complexes studied could increase the magnitude of the activity following the order: 2 > 1 > L^C5, where a linear relationship between the biological activity upon K562 cells (IC₅₀) and DNA binding studies (K_b) was found.

Influence of Complexation of Thiosemicarbazone Derivatives with Cu (II) Ions on Their Antitumor Activity against Melanoma Cells

A series of thiosemicarbazone derivatives was prepared and their anti-tumor activity in vitro was tested. The X-ray investigation performed for compounds T2, T3 and T5 confirmed the synthesis pathway and assumed molecular structures of analyzed thiosemicarbazones. The conformational preferences of the thiosemicarbazone system were characterized using theoretical calculations by AM1 method. Selected compounds were converted into complexes of Cu (II) ions. The effect of complexing on anti-tumor activity has been investigated. The copper(II) complexes, with Schiff bases T1, T10, T12, T13, and T16 have been synthesized and characterized by chemical and elemental analysis, FTIR spectroscopy and TGA method. Thermal properties of coordination compounds were studied using TG-DTG techniques under dry air atmosphere. G361, A375, and SK-MEL-28 human melanoma cells and BJ human normal fibroblast cells were treated with tested compounds and their cytotoxicity was evaluated with MTT test. The compounds with the most promising anti-tumour activity were then selected and their cytotoxicity was verified with cell cycle analysis and apoptosis/necrosis detection. Additionally, DNA damages in the form of a basic sites presence and the expression of oxidative stress and DNA damage response genes were evaluated. The obtained results indicate that complexation of thiosemicarbazone derivatives with Cu (II) ions improves their antitumor activity against melanoma cells. The observed cytotoxic effect is associated with DNA damage and G2/M phase of cell cycle arrest as well as disorders of the antioxidant enzymes expression.