Oxidovanadium(V) Complexes Anchored on Carbon Materials as Catalysts for the Oxidation of 1‐Phenylethanol

Six oxidovanadium(V) aroylhydrazone complexes derived from (3,5‐di‐ tert ‐butyl‐2‐hydroxybenzylidene)‐2‐hydroxybenzohydrazide (H 2 L 1 ) and (3,5‐di‐ tert ‐butyl‐2‐hydroxybenzylidene)‐2‐aminobenzohydrazide (H 2 L 2 ), namely, [VOL 1 (OEt)][VOL 1 (OEt) (EtOH)] ( 1 ), [VOL 2 (OEt)] ( 2 ), [Et 3 NH][VO 2 L 1 ] ( 3 ), [VO 2 (HL 2 )] ⋅ 2 EtOH ( 4 ), [(VOL 1 ) 2 (μ‐O)] ( 5 ), and [(VOL 2 ) 2 (μ‐O)] ( 6 ), were synthesized and characterized by elemental analysis, IR, 1 H NMR, and 51 V NMR spectroscopies, ESI‐MS and, for 1 – 5 , single‐crystal XRD. The compounds have VO 3+ ( 1 and 2 ), VO 2 + ( 3 and 4 ), and V 2 O 3 4+ ( 5 and 6 ) cores. They are active homogeneous catalysts in the microwave‐assisted, solvent‐free peroxidative oxidation of 1‐phenylethanol to acetophenone by t BuOOH. The immobilization of the oxidovanadium complexes ( 1 , 2 , 4 , and 5 ) on oxidized carbon materials improved the oxidation efficiency and allowed catalyst reuse with the preservation of activity.