Oxidation of Dimethylplatinum(II) Complexes with a Dioxirane: The Viability of Oxoplatinum(IV) Intermediates

The complexes [PtMe2(NN)] (NN = 2,2′-bipyridine
= bipy, 1a; NN = di-2-pyridylamine = dpa, 1b; NN = di-2-pyridyl ketone = dpk, 1c) react with dimethyldioxirane
in moist acetone to give the hydroxoplatinum­(IV) complexes [Pt­(OH)2Me2(NN)] (NN = bipy, 2a; NN = dpa, 2b, or [Pt­(OH)­Me2(dpkOH)], 3). Complex 2a crystallizes as the hydrate 2a·7H2O, which has a complex supramolecular network structure formed
through hydrogen bonding between PtOH groups and water molecules.
Attempts to trap a potential oxoplatinum­(IV) intermediate in these
reactions were unsuccessful, and computational studies suggest that
oxoplatinum­(IV) intermediates are improbable. It is suggested that
oxygen atom transfer from the dioxirane to platinum is coupled to
proton addition to give the hydroxoplatinum group directly.