Oxygen atom transfer to platinum(II): A 2-pyridyloxaziridine and a 2-pyridylnitrone as potential oxygen atom donors

The oxygen atom transfer reactions of 2-pyridyl-N-t-butyloxaziridine, pyox, with the dimethylplatinum(II) complex [Pt2Me4(μ-SMe2)2], 1, have been studied. In the presence of methanol or water, proton coupled oxygen atom transfer occurs, with displacement of dimethylsulfide ligands by the product ligand 2-pyridyl-N-t-butylmethanimine, pyim, to give initially the complexes [Pt(OH)(OR)Me2(pyim)], R = Me or H, respectively, which were slowly oxidized further to give the binuclear picolinate complexes [Pt2(μ-OR)2Me4(2-pyCO2)2], R = Me or H, respectively, and t-butylamine. The complex [Pt(OH)2Me2(pyim)] is also formed by oxidative addition of H2O2 to [PtMe2(pyim)], and the complex [Pt2(μ-OMe)2Me4(2-pyCO2)2] is also formed by reaction of 2-pyridyl-N-t-butylnitrone, pyNO, with complex 1 in methanol solution. The structures of several of the above complexes, as well as model complexes [PtXRMe2(pyim)], X = R = Cl; X = Cl or I, R = Me; X = Cl, R = CH2Cl, [PtMe(2-pyCO2)(dmso)] and [PtCl2(SMe2)(pyNO)], were determined to aid in characterization of new compounds. In the absence of a protic solvent, the oxaziridine group is still activated on reaction of pyox with complex 1 but a more complex mixture of products is formed.