Abstract
•Four new heteroleptic Pd(II) complexes containing a bidentate carbodithioate and a monodentate organophosphine were synthesized.•The synthesized complexes were tested for anticancer activity against HepG2 and found with excellent anticancer potential.•The complexes demonstrated low lethal effects and good antioxidant properties.
Four new potent anticancer palladium(II) complexes containing PdClPS2 coordination sphere have been synthesized and characterized by different analytical techniques. Here, P is the donor atom from organophosphine (triphenylphosphine (1 and 3) and tris(p-chlorophenyl)phosphine (2 and 4)) and S2 chelate is from carbodithioate (N,Nʹ-dibenzyl-1-carbodithioate (1 and 2) and 4-(2-hydroxyethyl)piperazine-1-carbodithioate (3 and 4)). All complexes exhibited distorted square planar geometry around Pd center owing to the chelate restriction of carbodithioate. The complexes are more potent anticancer (1-4) and antioxidant (3) agents than the standard drugs ((anticancer activity against HepG2: IC50 (µM) =23.39 (1) < 77.27 (3) < 82.62 (2) < 86.65 (4) < 110 (doxorubicin) and (antioxidant activity against DPPH 65.6 (%) (3) and total antioxidant capacity expressed as equivalent of ascorbic acid (3) 51.4 µg/mg, respectively)). Interestingly, the complexes demonstrated low lethal effects as determined by brine shrimp assay. The lethality sequence is opposite to that observed in anticancer (LD50 (ppm): 102.87 (1) > 65.54 (3) > 62.50 (2) > 39.82 (4)) indicating high selectivity of 1 and 3 towards cancer cells. Anticancer activities were found to depend on the molecular stability and axial protection offered by organophosphine of the complexes.
Pseudo square-planer geometry around Pd center was observed for complexes 1 and 2 with the help of single crystal analysis. The synthesized complexes were tested for their anticancer activity against HepG2 and found with excellent anticancer potential. The in vitro data was found to have good correlation with the theoretical and experimental data of molecular stability. [Display omitted]