The complexing ability of n-substituted thiourea derivatives as chelating ligands in the reaction with PdCl2

The complexation reactions of N-substituted thiourea derivatives with PdCl2 have been investigated in the present work. The functionally substituted thiourea derivatives are found to be effective chelating agents, in which the nature of substituents has a significant impact to the compositions and structures of complexes. Thus, (N-pyridine-2-yl)thioureas in the interaction with PdCl2 form two types of complexes in the molar ratio of M:L 1:1 and 1:2, in which they act as S,N-bidentate ligands coordinated to the palladium ion by thione sulphur and the nitrogen atom of the pyridine ring. The reaction of N-allylthioureas with PdCl2 in the equimolar ratio results in formation of the π-complexes where the ligands are coordinated by the thione sulphur and the C=C double bond of the allylic moiety. The preparative methods for the synthesis of this type of complexes have been developed. The composition of the products synthesized and the ligands coordination mode have been determined by elemental analysis and 1H NMR spectroscopy. Furthermore, the structure of compounds 4, 5 has been confirmed by the X-ray diffraction study. The biomedical studies have proven that the complex compounds 5 and 6 in vitro have the cytostatic and cytotoxic activity against tumour HeLa cells.