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

• Published in: Inorganica Chimica Acta Vol. 357; no. 3; pp. 853 - 858
• Main Authors: Keller, Barbara J, Hurst, Stephanie K, Dunham, Steven O, Spangler, Lee, Abbott, Edwin H, Peterson, Eric S
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 20.02.2004
• Subjects: Dimer; Oxalato; Partially oxidized; Platinum; Polymer; Polymer; Dimer; Oxalato; Platinum; Partially oxidized
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2003.09.009

Oxidation of a solution of [Pt II(Ox) 2] 2− leads to formation of an unbridged Pt III dimer, followed by formation of longer oligomers upon reaction with [Pt II(Ox) 2] 2− in the presence of H +. The solution equilibria of the oligomers and their acidity dependence was studied spectroscopically. 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.