Synthesis, characterization, in-silico, and in-vitro biological studies of Cu(II), Zn(II) complexes of semicarbazone, thiosemicarbazone derivatives of dehydrozingerone

Experimental and Computational Investigation of Cu(II) and Zn(II) complexes: DFT, Docking, and Anti-Lung Cancer Studies

AIMS

This study aimed to synthesize and characterize a Schiff base ligand, (Z)-2-(2-oxoindolin-3-ylidene)hydrazinecarbothioamide (1), and its copper(II) (2) and zinc(II) (3) complexes, as well as evaluate their binding interactions with the epidermal growth factor receptor (EGFR) and anticancer activity against the human lung cancer A549 cell line.

MATERIALS & METHODS

The Schiff base ligand was synthesized by refluxing isatin and thiosemicarbazide for 3 hours. Complexes 2 and 3 were formed and characterized using elemental analysis, molar conductivity, IR, NMR, and UV-Visible spectroscopy. The geometry of complex 3 was determined via X-ray diffraction. Theoretical calculations were conducted using DFT with the hybrid GEN B3LYP method. Molecular docking was performed to assess binding energies with EGFR, and anticancer activity was evaluated against the A549 cell line.

RESULTS

Characterization confirmed successful synthesis of the compounds. Zinc complexation led to notable spectral shifts, and X-ray diffraction revealed complex 3 adopted a distorted tetrahedral geometry. DFT analysis highlighted complex 2 with the lowest energy gap (0.331 eV). Docking results showed strong EGFR binding energies (-5.70, -5.54, and -7.30 kcal/mol). Complex 2 demonstrated the highest anticancer efficacy with a cell viability of 1.35% after 48 h.

CONCLUSIONS

Complex 2 exhibits significant anticancer potential and warrants further investigation as a therapeutic agent.

Synthesis, DFT, Molecular Docking, and Antimicrobial Studies of New Indole-Thiosemicarbazone Ligand and Their Complexes with Fe(III), Co(II), Ni(II), Cu(II)

Indole-3-carbaldehyde based novel ligand (E)-2-((1-benzyl-1H-indol-3-yl)methylene)-N-methylhydrazine-1-carbothioamide (MBIHC) and its metal complexes [(MBIHC)2FeCl2]Cl(C1), [(MBIHC-)2Co] (C2), [(MBIHC-)2Ni] (C3), and [(MBIHC-)2Cu] (C4) have been synthesized. All synthesized compounds have been characterized by various spectroanalytical techniques. The structure of MBIHC was confirmed by single-crystal X-ray data. The geometry of metal complexes was determined by spectroscopic and computational studies. In the case of iron complex, ligand MBIHC coordinated to the metal ion in bidentate mode (via nitrogen, sulphur donor atoms) while in the case of cobalt, nickel, and copper complexes ligand act as a tridentate ligand (via nitrogen, sulphur, carbene donor atoms). In vitro, antifungal and antibacterial studies of ligand and metal complexes were assayed against C. albicans, C. glabrata, E. coli, and K. pneumoniae pathogens. In antifungal activity, complex C1 exhibited a greater inhibition zone than the other compounds for the both examined fungi C. albicans (24±0.32 mm) and C. glabrata (20±0.16 mm). However, the antifungal activities of complex C2 has shown better activity against both E. coli (25±0.24 mm) and K. pneumoniae (16±0.80 mm) pathogens than the other examined compound. Complex C2 has found even better than the benchmark drug Ampiciline in case of E. coli. Further, the DFT calculations and molecular docking studies also validate the experimental bioactivity results of examined compounds.

Synthesis, In Silico, and Biological Applications of Novel Heteroleptic Copper (II) Complex of Natural Product-Based Semicarbazone Ligands

Recently, heteroleptic coordination between essential metallic elements with semicarbazone-based derivatives attracts more consideration for the varied ranges of bioactivities. Semicarbazone-based moiety holding azomethine (C=N) group become flexible ligands, forming stable complexes. Through a stirring and reflux technique, a novel heteroleptic complex of copper (II) was synthesized by reacting two semicarbazone-based derivative ligands, ortho-phthalaldehyde disemicarbazone (L1) and dehydrozingerone semicarbazone (L2), with copper chloride salt in 1 : 1 : 1 molar ratio. Magnetic moment measurement, elemental analyzer, thermogravimetric (TGA) analysis, and several spectroscopic techniques were applied to describe the prepared compounds. The disc diffusion and DPPH methods were actually used to investigate the antibacterial and antiradical potentials, respectively. The obtained data indicates the ligand (L1) has good mean inhibition zones on Staphylococcus aureus (12.42 ± 0.00 mm) and S. pyogenes (11.64 ± 0.12 mm) bacteria. The heteroleptic [Cu(L1) (L2)] complex displayed higher antibacterial actions (13.67 ± 0.52 mm) on Streptococcus pyogenes bacteria. The [Cu(L1) (L2)] complex also shows better antiradical potential (63.7%). Furthermore, the docking result of prepared compounds on S. aureus gyrase confirms the ligands (L1 and L2) and the complex potential molecules possess the smallest binding potential of −8.0 to −8.4 kcal/mol. A higher value was achieved by [Cu(L1) (L2)] complex (−8.4 kcal/mol). Thus, this study indicates an insight towards combining semicarbazone form derivatives of natural source origin with a synthetic compound as ligands through metal coordination could enhance bioactivity.