Chelation and Analytical Application of Thiosemicarbazides Toward Platinum(IV) Ions

N(1)H derivatives of ethyl- and phenyl-thiosemicarbazides have been prepared and identified so as to produce new complexes with H^sub 2^PtCl^sub 6^. The obtained complexes have been investigated by thermal, magnetic and spectral studies. They were found to be diamagnetic and to have an octahedral structure. The IR data reveal different modes of coordination for the investigated ligands. The thermal decomposition of some complexes ended with PtS^sub 2^ as a final product. The formation of a green associate with 1-phenyl-4-ethylthiosemicarbazide (HPETS) was found suitable for the preconcentration and determination of Pt(IV). A simple and effective separation-determination procedure was achieved through the use of the flotation technique. The deprotonation constants of the ligands and the stability constants of the complexes formed in solution were evaluated by electrochemical methods, Methylthiosemicarbazide (HMTS) complexes were found to be the most stable in solution.[PUBLICATION ABSTRACT]