Synthesis, Characterization, Photoluminescence Properties and Antiproliferative Activity of New Pd(II), Ni(II) and Cu(II) Mixed Complexes Bearing Schiff Base Ligand and 1,10-phenanthroline

In this study, new mixed ligand Cu(II), Ni(II) and Pd(II) metal complexes were synthesized and characterized by NMR (for ligand), UV-Vis, elemental analysis, FT-IR, molar conductivity techniques. While the octahedral structure is recommended for Cu(II) and Ni(II) complexes, the square plane structure is recommended for the Pd(II) complex. The compounds lack conductivity traits indicating their non-electrolyte nature in solution. Photoluminescence properties of the synthesized mixed ligand complexes were investigated. These three complexes showed emission bands when excited at their maximum absorbances. The excitation/emission bands of the Pd(II) complex shifted to higher (red) wavelengths when compared to the Cu(II) and Ni(II) complexes. The Pd(II) complex showed the Stokes shift of 26 nm. These metal complexes were screened for their anticancer activities against the colon cancer (DLD-1) and lung cancer (A549) cell lines. The results show that these complexes have antiproliferative activity. In particular, two of the complexes (Pd(II) and Cu(II)) were found to have a higher cytotoxic effect than the positive control drug cisplatin with low IC50 values.

Automated summary

New mixed ligand Cu(II), Ni(II), and Pd(II) metal complexes were synthesized and characterized using various techniques. The Cu(II) and Ni(II) complexes exhibited an octahedral structure, while the Pd(II) complex exhibited a square plane structure. The synthesized complexes showed emission bands upon excitation, with the Pd(II) complex having a higher shift in wavelength compared to the Cu(II) and Ni(II) complexes. These complexes also exhibited anticancer activity against colon and lung cancer cell lines, with two complexes showing higher cytotoxic effects than the positive control drug cisplatin.