Reactions of five-coordinate platinum(IV) complexes with molecular oxygen

Article abstract of DOI:10.1021/om4003363

The reactions of various five-coordinate Pt(IV) complexes with molecular oxygen have been studied. In arene solution, the complexes ( ^tBuMe2nacnac⁰)PtMe₃ (1; ^tBuMe2nacnac^- = [((4-tBu-2,6-Me₂C ₆H₂)NC(CH₃))₂CH]^-), (^Me3Me-nacnac)PtMe₃ (2; ^Me3Me-nacnac ^- = [((2,4,6-Me₃C₆H₂)NC(CH ₃))₂CCH₃]^-), and ( ^tBu2PyPyr)PtMe₃ (3; ^tBu2PyPyr^- = 3,5-di-tert-butyl-2-(2-pyridyl)pyrrolide) reacted immediately with oxygen to form peroxo species in which two oxygen atoms bridge between the metal center and a carbon atom in the ligand backbone. In contrast, no reaction between (^iPr2AnIm)PtMe₃ (4a; ^iPr2AnIm^- = [o-C₆H₄-{N(C₆H₃ⁱPr ₂)}(CHi - NC₆H₃ⁱPr ₂)]^-) or (^Me3AnIm)PtMe₃ (4b; ^Me3AnIm^- = [o-C₆H₄-{N(C ₆H₂Me₃)}(CHi - NC₆H ₂Me₃)]⁰) and oxygen was observed. As activation of oxygen by five-coordinate Pt(IV) species was found to involve cooperation between the metal center and the ligand, the ability of the ligand to participate in the oxygen binding appears to be a vital component. Oxygen atom transfer reactions of the novel peroxo species are also presented.