Charged dioxomolybdenum(VI) complexes with pyridoxal thiosemicarbazone ligands as molybdenum(V) precursors in oxygen atom transfer process and epoxidation (pre)catalysts

► Charged MoVI and MoV complexes derived from pyridoxal thiosemicarbazones. ► OAT agents. ► MoVI complexes as precatalysts. ► Good results in solvent free epoxidation of cyclooctene (0.05% [Mo] loading versus olefin).