Sustainable N2O2S Azomethine Transition Metal Complexes: Synthesis, Characterization, and Bioactivity

Abstract

This study uses ultrasonication pathways to create a new and environmentally friendly condensation reaction method. These pathways involve o-vanillin and thiocarbohydrazide coming together in a 2:1 molar ratio. The ligand is named as (thalvan) (1E,5E)-1,5-bis(2-hydroxy-3-methoxybenzylidene)thiocarbonohydrazide.The thalvan ligand is soluble in aprotic polar solvent like DMSO, DMF, acetonitrile, and dichloromethane. The metal acetates (M(OAc)₂, where M = Co(II), Ni(II), Cu(II), and Zn(II), undergo ultrasonic reactions with the thalvanligand to produce stable complexes. The ligands may include nitrogen, oxygen, and sulfur donor atoms. All complexes are synthesized in high yield by a equivalent ratio of the thalvan ligands with the corresponding metal salts. Spectral like Infrared (IR), UV-Vis, ¹H and ¹³C NMR, Mass, elemental, ICPMS, magnetic susceptibility, and conductivity studies have been employed to characterize this thalvan ligand and its coordinated complexes. The antibacterial capabilities against bacterial species, specifically Staphylococcus aureus (gram-positive) and Pseudomonas aeruginosa (gram-negative), as well as the antioxidant activity assessed using H₂O₂ and DPPH techniques, were evaluated for the azomethine thalvan ligand and their coordinated compounds.