Synthesis, X-ray crystal structures and anticancer studies of four Pd(II) dithiocarbamate complexes

Bis(piperidinyldithiocarbamato)palladium(II) ([Pd(Pipdtc)2]), bis(1-phenylpiperazinyldithiocarbamato)palladium(II) [Pd(1-PhPzdtc)2], bis(phenyldithiocarbamato)palladium(II) ([Pd(Phdtc)2]) and bis(4-benzylpiperidinyl)palladium(II) ([Pd(4-BenzPipdtc)2]) were prepared and characterized by elemental analysis, spectroscopic techniques and single crystal X-ray crystallography. Molecular structures of the Pd(II) complexes revealed square planar PdS4 geometry in which each Pd(II) is coordinated to two chelating dithiocarbamato anions. [Pd(Pipdtc)2] and [Pd(1-PhPzdtc)2] crystallized in monoclinic P21/c space group while [Pd(Phdtc)2] and [Pd(4-BenzPipdtc)2] crystallized in triclinic P-1 space group. Cytotoxic studies of the dithiocarbamate ligands and corresponding Pd(II) dithiocarbamate complexes were tested against three human cell lines: Cervical cancer, breast adenocarcinoma, and epithelial colorectal adenocarcinoma at four different concentrations. All the compounds displayed high to moderate potency against the cell lines. [Pd(Pipdtc)2] and [Pd(Phdtc)2] are very potent against the three cell lines and are more active than the corresponding dithiocarbamate ligands whereas the anticancer potency of 1-PhPzdtc-Na and 4-BenzPipdtc-Na are generally higher than the corresponding Pd(II) complexes.