Pd(II)-based heteroleptic complexes with N-(acyl)-N', N'-(disubstituted) thioureas and phosphine ligands: Synthesis, characterization and cytotoxic studies against lung squamous, breast adenocarcinoma and Leishmania tropica

A series of palladium (II) complexes (1-8) with N-(acyl)-N',N'-(disubstituted) thioureas and phosphine ligands were synthesized and characterized by FT-IR, multinuclear (H-1, C-13 & P-31) NMR spectroscopy and elemental analysis. The crystal structures of the Pd(II) complexes (1) & (5) of the type Pd-II(L-O,S) (L-P)Cl were determined by single crystal X-ray diffraction analysis. They adopted the square planar geometry, where the N-(acyl)-N', N'-(disubstituted) thioureas showed bidentate coordination mode in a chelating fashion through O and S donor atoms, and phosphine ligands through P atom at palladium centre. In vitro cytotoxic profile of the synthesized palladium(II) complexes (1-8) was determined against lung squamous carcinoma and breast adenocarcinoma cell lines. These complexes were also tested for promastigote forms of Leishmama tropica to evaluate their antileishmanial activity. The complexes bearing 2,4-dichlorophenyl moiety among the screened complexes were the most active with IC50 values 1.72 +/- 0.27, 2.12 +/- 0.44, 1.57 +/- 0.16 gM against the targets MDA-MB-231, H-157, Leishmama tropica, respectively.