Polymorphism, spectroscopic, DFT and anticancer activity of a palladium(II) complex with a thiophenyl azoimine-quinoline SNN’N” ligand

Two polymorphs based on a new Pd(II) complex, [[Pd(Y)] (H2Y = (2-SR)C6H4NHN=C(COCH3)-NHC9H6N; R=C6H5) have been characterized by FTIR, UV/Vis, elemental analysis and 1H NMR. Quantum theory of atoms in molecules was used to analyse the bonding in the two polymorphs. The UV/Vis spectra were calculated using time-dependent density functional theory (TD-DFT). The cytotoxic activities of the ligand and its complex were evaluated against seven cancer cell lines and one normal skin fibroblast cell line. The complex is more active than the ligand for all cancer cell lines and shows no cytotoxicity against the normal skin fibroblast cell line. The complex is more active against DU145, MCF7, MDA231 and HCT116 cell lines with IC50 values in the range 0.143-0.492 μMs, whereas it is less active against A375, A549 and PanC-1 cell lines, with IC50 values in the range 6.16-10.84 μM. With the exception of PanC-1, the ligand is also active against six cell lines with IC50 values ranging from 57.3-866.5 μM.