Oxidative halogenation of cisplatin and carboplatin: synthesis, spectroscopy, and crystal and molecular structures of Pt(IV) prodrugs.

A series of Pt(IV) prodrugs has been obtained by oxidative halogenation of either cisplatin or carboplatin. Iodobenzene dichloride is a general reagent that cleanly provides prodrugs bearing axial chlorides without the need to prepare intervening Pt(IV) intermediates or handle chlorine gas. Elemental bromine and iodine afford Pt(IV) compounds as well, although in the case of the iodine-mediated oxidation of carboplatin, an amido-bridged Pt(IV) side product also formed. A detailed analysis of the changes in spectroscopic and structural parameters induced by varying the axial halide is presented. A number of recurring motifs are observed in the solid state structures of these compounds.