Synthesis, characterization and in vitro cytotoxicity of homobimetallic complexes of palladium(II) with 2‐thiouracil ligands. Crystal structure of [Pd 2 (TU)(PPh 3 ) 3 Cl 2 ]

Square planar metallic and homonuclear bimetallic complexes of Pd(II) with 2‐thiouracil (HTU) and organophosphines have been synthesized and characterized by FT‐IR and multinuclear 1 H, 13 C, 31 P NMR spectroscopy. The thiouracil ligand TU acts as bidentate, is bound through the thioxo moiety and the endo amino group and forms a bridge between a PdCl(R 3 P) and a PdCl(R 3 P) 2 moiety [R 3 P = Ph 3 P ( o ‐tolyl) 3 P, ClPh 2 P] in the homonuclear bimetallic complexes. The square planar geometry around Pd(II) has been confirmed for these complexes by a single‐crystal X‐ray diffraction study of compound 1 , [Pd 2 (TU)(PPh 3 ) 3 Cl 2 ]. These compounds were also screened against human tumor cell lines and showed promising in vitro cytotoxicity. Copyright © 2007 John Wiley & Sons, Ltd.