Unprecedented water addition to the α,β-unsaturated enone bond, mediated by the combination of carbonate and platinum(II).

The cytostatic compounds cis-[Pt(A9pyp)(dmso)Cl(2)] (1) and [Pt(A9pyp)(dmso)(cbdca)] (2) (A9pyp=(E)-[1-(9-anthryl)-3-(2-pyridyl)-2-propenone) as carrier ligand; cbdca=cyclobutane dicarboxylate) have been found to add water across the enone C==C bond of the ligand A9pyp. The water addition occurs in the presence of carbonate buffer, and has been followed in detail using NMR and ESI-MS spectroscopy. The spectroscopic data clearly indicate that the platinum(II) ion, the carbonate species, and the proximity of the enone C==C bond to the metal ion, are all required for this unusual hydration. A difference in kinetics is observed between chloride and cbdca, showing that the Pt-ligand dissociation plays an important role in the hydration kinetics.