Synthesis and Catalytic Epoxidation Activity With TBHP and H2O2 of Dioxo-, Oxoperoxo-, and Oxodiperoxo Molybdenum(VI) and Tungsten(VI) Compounds Containing Monodentate or Bidentate Phosphine Oxide Ligands: Crystal Structures of W(O)2(Cl)2(OPMePh2)2, W(O)(O)2(Cl)2(OPMePh2)2, Mo(O)2(Cl)2dppmO2C4H10O, W(O)2(Cl)2dppmO2, Mo(O)(O2)2dppmO2, and W(O)(O2)2dppmO2
