5-Methyl-2-hydroxy-acetophenone-S-methyl-thiosemicarbazone and its nickel-PPh3 complex. Synthesis, characterization, and DFT calculations

Synthesis, cytotoxicities, structural properties and comparison of dihalogeno-substituted-thiosemicarbazone ligands and mixed-ligand Ni(II) complexes

Three novel mixed-ligand Ni(ıı) complexes were synthesized from a 3,5-dihalogenosalicylaldehyde-S-methyl isothiosemicarbazone ligand (3,5-dichloro for Complex I, 3,5-dibromo for Complex II, and 3,5-diiodo for Complex III) and diethanolamine. The synthesized compounds were characterized by elemental analysis, FT-IR, UV-Vis and 1H-NMR spectroscopy. Solid-state structures of Complex I and Complex II were determined by the single-crystal X-ray diffraction technique. Both the complexes were found to have a distorted square planar geometry, with coordination of azomethine nitrogen, phenolate oxygen, terminal amine of the thiosemicarbazone ligand and amine nitrogen of diethanolamine. The cytotoxic effects of the ligands and the complexes were evaluated against two different types of cancer cells (THP-1 human leukaemia monocytic cell line and MDA-MB-231 aggressive breast cancer cell line) and healthy cells (HUVEC human umbilical vein endothelial cell line) by using the MTT method. The findings demonstrated that the chloro-derivatives exhibited better efficacy compared to cisplatin in targeting the monocytic leukemia cell line while displaying reduced toxicity towards healthy cells.

Design, synthesis and characterization of novel Ni(II) and Cu(II) complexes as antivirus drug candidates against SARS-CoV-2 and HIV virus

This paper describes the structure-based design, synthesis and anti-virus effect of two new coordination complexes, a Ni(II) complex [Ni(L)2] (1) and a Cu(II) complex [Cu(L)2] (2) of (E)-N-phenyl-2-(thiophen-2-ylmethylene) hydrazine-1-carbothioamide(HL). The synthesized ligand was coordinated to metal ions through the bidentate-N, S donor atoms. The newly synthesized complexes were characterized by various spectroscopic and physiochemical methods, powdered XRD analysis and also X-ray crystallography study. Ni(II) complex [Ni(L)2](1) crystallize in orthorhombic crystal system with the space group Pbca with four molecules in the unit cell (a = 9.857(3) Å, b = 7.749(2) Å, c = 32.292(10) Å, α = 90°, β = 90°, γ = 90°, Z= 4) and reveals a distorted square planar geometry. A Hirshfeld surface and 2D fingerprint plot has been explored in the crystal structure of Ni(II) complex [Ni(L)2] (1). Energy framework computational analysia has also been explored. DFT based calculations have been performed on the Schiff base and its metal complexes to study the structure-property relationship. Furthermore, the molecular docking studies of the ligand and its metal complexes with SARS-CoV-2 virus (PDB ID: 7BZ5) and HIV-1 virus (PDB ID: 6MQA) are also investigated. The molecular docking calculations of the Ni(II) complex [Ni(L)2] (1) and a Cu(II) complex [Cu(L)2] (2) with SARS-CoV-2 virus revealed that the binding affinities at inhibition binding site of receptor protein are 9.7 kcal/mol and -9.3 kcal/mol, respectively. The molecular docking results showed that the binding affinities of Ni(II) complex (1) and Cu(II) complex (2) against SARS-CoV-2 virus were found comparatively higher than the HIV-1 virus (-8.5 kcal/mol and -8.2 kcal/mol, respectively). As potential drug candidates, Swiss-ADME predictions analyses are also studied and the results are compared with Chloroquine (CQ) and Hydroxychloroquine (HCQ) as anti-SARS-CoV-2 drugs.