Abstract. New cis-dioxomolybdenum (VI) complexes (MoO 2 Y x CH 3 OH) were synthesized using MoO 2 (acac) 2 and 2 [(1-hydroxy-2-methylpropane-2-ylimino) methyl] phenol derivatives as tridentate ONO donor Schiff base ligands (H 2 Y x). MoY 1 was crystallized in orthorhombic space group Pbca. The epoxidation of olefins using tert-butyl hydroperoxide and oxidation of sulfides to the sulfoxides by hydrogen peroxide were efficiently enhanced ...