The College of Education for Pure Sciences, Department of Chemistry, has conducted a master's thesis on (Preparation, Characterization, Theoretical and Biological Study of Some Thiourea Benzamide Derivatives and Their Complexes with Cobalt and Ruthenium). The thesis, presented by the researcher (Fatima Ghanem Mahawi), included three interconnected research axes. In the first framework of the research, five new organic ligands (L1–L5) derived from 4-ethylbenzoylthiourea were prepared, and the cobalt(II) and ruthenium(II) coordination complexes of Thiourea Benzamide derivatives were prepared. The prepared ligands were characterized using a set of spectroscopic and analytical methods, including EI-MS, FT-IR, NMR for both proton and carbon, in addition to TGA, UV-Vis and ESI-MS for their complexes. Molar conductivity measurements and magnetic properties were also performed to determine the nature of the coordination and geometric structure, while the inductively coupled plasma atomic emission spectroscopy (ICP-AES) technique was used to calculate the percentages of metals within the complexes. In the second axis, the biological activity of the ligands and their complexes against breast cancer cells (MCF-7) was evaluated using the MTT assay. The study revealed that thiourea benzamide derivatives have good inhibitory activity against the breast cancer cell line (MCF-7), as the IC50 value for one of the studied compounds was 9.81 (μg/mL). The third axis of the research included computational studies using the Gaussian 09 program using density functional theory (DFT), where geometric optimizations were performed for the prepared ligands at the B3LYP level and the (d,p) G31 6- basis system, where it was observed that there is a match between the theoretical values ​​and the experimental values. Molecular docking simulations were performed for the most potent inhibitory compounds against breast cancer cell line (MCF-7). The compounds showed the strongest binding to 5KCV and 3ERT proteins, giving the lowest binding energy (S) values ​​with the lowest RMSD values

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