A new family of doubly cyclopalladated diimines. A remarkable effect of the linker between the metalated units on their cytotoxicity

Article abstract of DOI:10.1021/om500382f

The cyclopalladation of a series of symmetric diimines with the formula (RC₆H₄CH=NZ)₂, where Z = CH₂ or (CH₂)₂OCH₂ and R = p-Cl, p-OMe, p-NO ₂, and o-Cl, is described. Optimal conditions to obtain the dimetalated compounds were found to be palladium(II) acetate, in toluene, at 60 °C and with a reaction time of 2-4 h. The reactivity of the dimetalated compounds with monodentate, bidentate, and bis(monodentate) Lewis bases was also studied. The cytotoxic activity of some selected compounds was evaluated against a panel of adenocarcinoma cell lines (colon HCT116 and breast MCF7 and MDA-MB231). Compounds containing the fragment NCH₂CH ₂OCH₂CH₂OCH₂CH₂N exhibited a remarkable cytotoxic activity in the three cancer cells assayed, but complexes containing the NCH₂CH₂N fragment showed no activity. It seems that the length and flexibility of the central saturated chain in the imine molecule, as well as its lipophilicity and hydrophilicity, explain the different cytotoxicity of the two series of coordination compounds here reported.