Dioxomolybdenum(VI) complexes of hydrazones of two substituted salicylaldehydes: synthesis, structures, and catalytic properties

Dioxomolybdenum(VI) complexes [MoO₂L(CH₃OH)] (L = L¹ = N′-(2-hydroxy-5nitrobenzylidene)isonicotinoylhydrazide for 1, L = L² = N′-(4-diethylamino-2-hydroxybenzylidene)-4-methylbenzohydrazide for 2) were prepared and structurally characterized by physicochemical and spectroscopic methods and single-crystal X-ray determination. Mo in the complexes is octahedrally coordinated. Both complexes show effective catalysis in oxidation of cyclohexene, vinylbenzene, 1-butylene, and 1-pentene, to their corresponding epoxides. In general, high epoxide yields (over 89%) and selectivity (100%) were observed for all aliphatic and aromatic substrates.