The first chelating phosphorus–nitrogen dioxo ligand: complexation of an MoO(O 2 ) 2 fragment

2-Diphenylphosphinoyl-N,N-dimethylaniline is oxidized at nitrogen by a dilute solution of H2O2 in the presence of MoO(O2)2·(H2O)x; the resulting phosphorus–nitrogen dioxo-ligand forms a molybdenum oxobisperoxo complex, which is structurally characterized by single crystal X-ray diffraction.