High-valent oxo complexes of osmium as selective oxidants for cyclohexene oxidation. Complexation of the bisamide tetradentate ligand bpb to osmium and the X-ray structure of trans-[os III (bpb)(PPh 3 )Cl][bpbH 2 =N,N′-bis(2′-pyridine-carboxamide)-1,2-benzene]

The reaction of N,N′-bis(2′-pyridinecarboxamide)-1,2-benzene (bpbH2) with K2[OsO2(OH)4] yielded trans-[OsVI(bpbH2)O2]2+ which in turn gave trans-[OsIII(bpb)(PPh3)Cl] upon treatment with PPh3; the OsIII complex has been characterized by X-ray crystallography and found to catalyse the epoxidation of cyclohexene in the presence of iodosobenzene.