Synthesis and Anticancer Activity of Palladium‐Butadienyl Complexes Bearing Picolyl‐NHC and Phosphine Ligands

This work presents the synthesis and full characterization of Pd(II)-butadienyl complexes incorporating picolyl-NHC or phosphine ligands (PPh3 or PTA). These complexes were evaluated against four different cancer cell lines and human lung fibroblasts. Our findings indicate a slightly lower antiproliferative activity of picolyl-NHC Pd(II)-butadienyl complexes compared to recently published ones featuring N−N, P−P, and C−C ligands but, above all, they exhibited selectivity for ovarian cancer cells. Additionally, trans-[PdX (phosphine)2C4(COOMe)4Y)] derivatives (X=Br, Cl and Y=CH3, Br) proved excellent anticancer activity across all tested cancer cell lines, especially the bisPTA complexes. Importantly, the IC50 values suggest minimal impact from the halide coordinated to palladium or that present in the butadienyl terminal position. Furthermore, the low activity observed towards non-cancerous cells underscores the potential of these synthesized Pd(II)-butadienyl compounds as promising candidates for further investigation in anticancer research.