A new Schiff base (H2L) generated from sulfamethazine (SMT), as well as its novel micro- and nanocomplexes with Ni(II) and Cd(II) metal ions, have been synthesized. The proposed structures of all isolated solid compounds were identified with physicochemical, spectral, and thermal techniques. Molar conductance studies confirmed that the metal complexes are not electrolytic. The molecular geometry located at the central metal ion was found to be square planar for the NiL2 and tetrahedral for the CdL2 complexes. The kinetic and thermal parameters were obtained using the Coats and Redfern approach. Coriandrum sativum (CS) in ethanol was used to create the eco-friendly Ni and Cd nanocomplexes. The size of the obtained nanoparticles was examined using PXRD and TEM, and found to be in the sub-nano range (3.07-4.61 nm). Furthermore, the TEM micrograph demonstrated a uniform and homogeneous surface morphology. The chemistry of the prepared nanocomplexes was studied using TGA and TEM techniques. The effect of temperature on the prepared nanocomplexes' size revealed a decrease in size by heating. Furthermore, the nanocomplexes' antimicrobial and anticancer properties were evaluated. The outcomes demonstrated that the nanocomplexes exhibited better antimicrobial properties. Moreover, the antitumor results showed that after heating, the Ni nanocomplex exhibited a substantial antitumor activity (IC50 = 1.280 g/mL), which was higher than the activity of cis-platin (IC50 = 1.714 g/mL). Finally, molecular-docking studies were performed to understand the evaluated compounds' ability to bind to methionine adenosyl-transferases (PDB ID: 5A19) in liver cancer and COVID-19 main protease (PDB ID: 6lu7) cell-proteins. The findings reveal that [NiL2]·1.5H2O2 has a higher binding energy of -37.5 kcal/mol with (PDB ID: 5A19) cell protein.
Keywords: COVID-19; DFT; anticancer activity; antimicrobial activity; green synthesis; kinetic parameter; nanocomplexes.