## 4 Conclusions  
The present work describes the synthesized and characterized of a Schiff base and their metal complexes by analytical and spectroscopic studies. The IR spectra showed a new band at 400 for M-O and 500 M-N indicating that the ligand successfully coordinated to Cu ions through the N, O system and by tridentate system (N, N, O) with other metals ions. The molar ratio data reveal that the ligand to metal ratio is 1:2 for Co(II) Cu(II) and Zn(II), and 1:1 for Mn(II) and Ni(II) complexes. The thermal analysis explained the number of water molecules in the metal complexes. The proposed structures of metal complexes were confirmed by optimizing the geometry of the complexes by the DFT method. The energy gap, E\({}_{\text{GAP}}\), for the complexes was lower than that of the ligand, which indicated high activity for the metal complexes. The DNA binding, molecular docking analysis, and anticancer studies suggested that the Schiff base metal complexes were found to be biologically active. The metal complexes showed efficient activity of three cell lines cancer (Ovra3), (M14), and (HOP-62); notably, Cu complex for (HOP-62) showed great results for the safety of the drug used in vivo. The following are available online at [[https://www.mdpi.com/article/10.3390/app11199067/s1](https://www.mdpi.com/article/10.3390/app11199067/s1)]([https://www.mdpi.com/article/10.3390/app11199067/s1](https://www.mdpi.com/article/10.3390/app11199067/s1)), Table S1: comparison between characteristic IR bands experimental and theoretical values, Table S2: major 1H NMR data for ligand and Zn(II) complex, Table S3: experimental data of Cu(II) complex by molar ratio, Table S4: thermoanalytical result of the ligands and their complexes, Table S5: thermodynamic data of thermal decomposition of ligands and its uranyl complexes. Figure S1. IR spectra for ligand and their metal complexes, Figure S2. 1H NMR spectra of Schiff base ligands (a) and Zn(II)complex (b), Figure S3. The electronic spectra of ligand and their complexes, Figure S4. Absorption spectra of (a) Zn(II) complex and (b) the Ni(II) complex in a Tris-HCl buffer upon addition of DNA. The change in the absorbance upon increasing the concentration of DNA is indicated with arrows. Synthesis and characterizations, H.B.H. ; supervision and writing original draft preparation, A.S.B. and M.A.H. ; theoretical calculation, review, and editing; A.A.S. ; biological studies, interpretations, and English Editing M.H.A. All authors have read and agreed to the published version of the manuscript. This research received no external funding. **Data Availability Statement:** All relevant data are within the manuscript and its supporting material. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Code**} & \multicolumn{8}{c}{**Types of Cell Cancer**} \\ \cline{2-9}  & \multicolumn{3}{c}{**Ovra3 (Ovarian)**} & \multicolumn{3}{c}{**M14 (Melanoma)**} & \multicolumn{3}{c}{**HOP-62 (NSCLC)**} \\ \hline  & **SD** & **IC50** & **LD50** & **SD** & **IC50** & **LD50** & **SD** & **IC50** & **LD50** \\ L & 0.05 & 18.92 & 430 & 0.08 & 14.8 & 410 & 0.014 & 17.45 & **377** \\ Zn(II) & 0.001 & 9.67 & 480 & 0.002 & 9.78 & 435 & 0.001 & 10.01 & **370** \\ Cu(II) & 0.005 & 4.17 & 375 & 0.005 & 5.2 & 388 & 0.028 & 11.27 & **385** \\ Ni(II) & 0.018 & 8.72 & 389 & 0.024 & 9.4 & 392 & 0.021 & 11.1 & **396** \\ Co(II) & 0.001 & 9.79 & 480 & 0.025 & 8.97 & 435 & 0.001 & 9.45 & **370** \\ Mn(II) & 0.03 & 5.44 & 401 & 0.005 & 6.33 & 376 & 0.035 & 9 & **399** \\ \hline \hline \end{tabular}
\end{table} 
Table 6: In vitro anticancer activity of (Ovra3), (M14), and (HOP-62) cancer cell lines. **Acknowledgments:** We thank King Fahad Medical Research Center for the use of their facilities and support.