Environmental and greener synthesis: Characterization and biological significance of some transition metal complexes

Modern industrialization has led to significant environmental degradation. Microwave-assisted synthesis, a key approach in green chemistry, offers sustainable alternatives for various applications. This technique finds utility across multiple fields, including biotechnology, pharmaceuticals, petrochemicals, plastics, chemicals, and more. Its main uses have been found in analytical chemistry and chemical synthesis. Since microwave dielectric heating has been used successfully in industrial instruments, it is now being used more and more in chemical reactions. Coordination complexes of Co(II), Ni(II), and Cu(II) with the Schiff base obtained from 3-nitrobenzaldehyde and thioacetamide (SB), have been synthesized using both conventional and microwave-assisted methods. These compounds have been characterized through various analytical and spectral techniques such as- elemental analysis, FT-IR spectroscopy, molar conductance measurements, electronic spectra, ESR, magnetic susceptibility, and thermal analysis. The complexes are colored and stable under atmospheric conditions. Analytical data indicate that all the complexes demonstrate a 1:2 metal-to-ligand ratio. Thermal analyses further reveal their degradation patterns and stability. The Schiff base and its metal complexes display significant activity against bacteria such as S. typhi, E. coli, and B. subtilis, as well as fungi including A. niger, F. oxysporum and C. albicans. Antimicrobial assessments further suggest that the metal complexes possess superior antimicrobial efficacy compared to the Schiff bases ligand.