Solution equilibria leading to the formation of metal–metal bonds in partially oxidized bisoxalatoplatinate(II) systems

The reaction between [PtII(Ox)2]2− and an appropriate oxidant resulted in the formation of the dimeric unbridged platinum complex [{PtIII(Ox)2 }2]2− where (Ox) is oxalate. This complex was moderately stable under ambient conditions and was studied via a variety of NMR and spectrophotometric techniques. Reaction of the [{PtIII(Ox)2}2]2− complex with [PtII(Ox)2]2− in the presence of H+ lead to the formation of a series of longer platinum oligomers with non-integral oxidation states, culminating in the formation of partially oxidized platinum polymers of general formula [{Pt(Ox)2}n]n−. The concentration of H+ was an important factor leading to higher oligomers and the approximate number of protons associated with each oligomer was determined. The analogous [{PtIII(Mal)2}2]2− complex, where (Mal) is the malonate anion, was also synthesized and studied but was shown to be significantly less stable.