Synthesis and Spectroscopic Study of Biologically Active Tridentate Schiff’s Base Ligand 2-Acetyl-5-methyl-furanthiosemicarbazone and its Mn(II), Co(II), Ni(II), and Cu(II) Complexes

Bioactive Thiosemicarbazone Coordination Metal Complexes: Synthesis, Characterization, Theoretical analysis, Biological Activity, Molecular Docking and ADME analysis

Mn(II) and Cu(II) complexes having the formula [M(L)2 ]X2 of ligand, i. e., 2-acetyl-5-methylfuranthiosemicarbazone were synthesized. Various analytical and spectroscopic techniques described the structure of synthesized complexes. Molar conductance confirmed the electrolytic nature of the complexes. The theoretical study of the complexes explained the structural property and reactivity. The chemical reactivity, interaction and stability of the ligand and metal complexes were studied with the help of global reactivity descriptors. MEP analysis was used to investigate the charge transfer in the ligand. The biological potency was evaluated against two bacteria and two fungi. Complexes demonstrated superior inhibitory action to ligand. The inhibitory effect was also checked at the atomic scale using molecular docking, which confirmed the experimental results. Cu(II) complex was shown to have the most inhibitory effect in experimental and theoretical studies. To check the bioavailability and drug-likeness, ADME analysis was also done.

Hydrolysis of Schiff bases with phenyl-ethynyl-phenyl system: The importance for biological and physicochemical studies

A series of new Schiff bases containing the phenyl-ethynyl-phenyl system was synthesized and their thermal stability, photophysical and electrochemical properties were investigated. Moreover, DFT calculations were performed to obtain the optimized ground-state geometry and distribution of the HOMO and LUMO levels as well as IR spectra of the prepared compounds. It was found that, the photoluminescence of synthesized imines was negligible in all investigated organic solvents except for the PBS/ACN mixture. As was proved in further studies, this phenomenon was related to the partial hydrolysis of imines, which is the source of the fluorogenic aldehyde causing the aggreggacion incrased-emision effect. In further research, due to the susceptibility of the azomethines to partial hydrolysis, the biological activity of 2-{(E)-[4-(phenylethynyl) phenyl]imino}phenol (1b), substrate (2-aminophenol) and Cu(II)-1b complex was analyzed. The biological tests showed, that 1b (as example of imine resveratrol analogue), demonstrated its increased cytostatic activity in prostate cancer cellular system. It was proved that the non-hydrolyzed imine was crucial for the cytotoxic effect. This activity could be ascribed to its Cu(II) complexing capability as showed in our previous research.