Highly efficient divanadium(V) pre-catalyst for mild oxidation of liquid and gaseous alkanes

• New binuclear V(V) complex bearing an NO2-donor Schiff base ligand is synthesized.
• This compound is highly active catalyst precursor in the oxidation of alkanes by H2O2.
• 2-Pyrazinecarboxylic acid acts as an efficient co-catalyst.
• High yields (up to 45% based on alkanes) and TONs (up to 7800) are achieved.
• Oxidation proceeds via radical mechanism with participation of hydroxyl radicals.

A new binuclear oxovanadium(V) complex bearing an NO2-donor Schiff base ligand, [{VO(EtO)(EtOH)}2(1κ2O,κN:2κ2O,κN-L)]·2H2O (H4L = bis(2-hydroxybenzylidene)oxalohydrazonic acid) was prepared and fully characterized by IR, 1H NMR and electronic spectroscopies, elemental analysis and single crystal X-ray diffraction. In the presence of 2-pyrazinecarboxylic acid (PCA) or another acid promoter, this compound acts as a highly efficient pre-catalyst towards the oxidation of gaseous and liquid alkanes by aqueous H2O2 under mild conditions, in aqueous MeCN. Total yields of oxygenates up to 45% and overall turnover numbers up to 7.8 × 103 are achieved.

Figure optionsDownload high-quality image (174 K)Download as PowerPoint slide