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

The reaction between [Pt-II(Ox)(2)](2-) and an appropriate oxidant resulted in the formation of the dimeric unbridged platinum Complex [{Pt-III(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 [{Pt-III(Ox)(2)}(2)](2-) complex with [Pt-II(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 [{Pt-III(Mal)(2)}(2)](2-) complex, where (Mal) is the malonate anion, was also synthesized and studied but was shown to be significantly less stable. (C) 2003 Elsevier B.V. All rights reserved.