Heteroleptic Pd(II) dithiocarbamates: synthesis, characterization, packing and <i>in vitro</i> anticancer activity against HeLa cell line

<div><p>Two new heteroleptic Pd(II) dithiocarbamates (<b>1</b> and <b>2</b>) have been synthesized by reaction of equimolar quantities of palladium(II) chloride, sodium 4-(3-methoxyphenyl)piperazine-1-carbodithioate, and appropriate substituted triphenylphosphines. The synthesized complexes have been characterized by their physical, spectral (IR, ¹H, ¹³C, and ³¹P NMR), and X-ray crystallographic data. Complexes <b>1</b> and <b>2</b> showed square-planar geometry both in solution and solid states. The crystal packing of both complexes revealed similar 3-D-supramolecular networks comprised of 1-D chains. However, the nature and strength of various non-covalent interactions of these networks were slightly different. The DNA interaction studies of the complexes have been carried out by UV–visible spectroscopy to evaluate their anticancer potential. The study suggested intercalative interaction with 2.402 × 10⁴ and 2.713 × 10³ M⁻¹ binding constants, respectively. The complexes have also been evaluated for their anticancer activity against HeLa cell line. Both complexes showed higher activity with IC₅₀ values much lower (22.176 and 26.166 μM for <b>1</b> and <b>2</b>, respectively) than the standard cisplatin (78.075 μM). Furthermore, the complexes induced stronger DNA fragmentation as investigated by DNA ladder assay for apoptosis. Our findings suggested that the anticancer action of these compounds stems from their interaction with DNA leading to DNA damage and apoptosis. The excellent activity of <b>1</b> and <b>2</b> deserves to be a focus for further research and <i>in vivo</i> studies.</p></div