Heterogeneous catalytic oxidation of styrene by an oxo bridged divanadium(V) complex of an acetohydrazide-Schiff base

We have synthesized a μ-oxido divanadium compound [(VOL)2(μ-O)] with an aliphatic hydrazone ligand LH2 = (E)-N′-(1-(2-hydroxyphenyl)ethylidene)acetohydrazide. The complex was characterized by elemental analysis, IR and UV–Vis spectroscopy and the molecular structure was established by single crystal X-ray diffraction technique. The complex has been infused over alumina to prepare a heterogeneous catalyst which was characterized by IR spectroscopy, thermogravimetric and powder XRD analyses. The catalyst has been studied for the oxidation of styrene in presence of H2O2 and appears to be easily recyclable. A conversion of 99.7% and selectivity of 88.1% for benzaldehyde formation and a turnover number of 1354 was detected under the most favorable reaction conditions.

Graphical abstractA μ-oxido divanadium(V) compound has been synthesized with an alkyl hydrazone Schiff base. The [V2O3]4+ core has a unique conformation with considerably small V–O–V bridge angle. The complex, heterogenized over alumina, acts as an efficient catalyst for the oxidation of styrene to benzaldehyde with 88.1% selectivity and TON 1354.Figure optionsDownload full-size imageDownload as PowerPoint slide