Oxidation of phenyl PtII complexes K [(dpms) PtIIPh2], 1,(dpms) PtIIPh (MeOH), 2,(dpms) PtIIPh (OH2), 3, and methyl PtII complex (dpms) PtIIMe (NH2Ph), 6, with O2 in aqueous or methanol solutions under ambient conditions leads to corresponding (dpms) PtIVR (X) OH