Binuclear cobalt complex with Schiff base ligand: Synthesis, characterization and catalytic properties in partial oxidation of cyclohexane

A new binuclear cobalt complex with Schiff base ligand and amino acid was synthesized and characterized using XRD, elemental analysis, IR spectroscopy, XPS and electrochemical measurements. The presence of cobalt in the oxidation state 3+ in this complex was proved. The catalytic activity of this complex was investigated in the reaction of partial cyclohexane oxidation with air, and high activity and selectivity for cyclohexanol and cyclohexanone formation were demonstrated. The possibility of complex reuse in cyclohexane oxidation was studied and it was shown that the activity slightly decreases in a second oxidation cycle along with changes in main product distribution due to partial transfer of Co3+ to Co2+.

The complex CoL with structure shown in abstract catalyzes partial oxidation of cyclohexane (CyH) with formation of cyclohexyl hydroperoxide (CyOOH), cyclohexanol (CyOH), cyclohexanone (CyO) and acids. The comparison of main product selectivities for noncatalytic and CoL catalyzed CyH oxidation are given.Figure optionsDownload as PowerPoint slideHighlights
► New binuclear cobalt complex with Schiff base was synthesized.
► The complex structure was characterized by IR spectroscopy and X-ray diffraction.
► Oxidation state of Co was studied by electrochemical measurements and XPS.
► Cobalt complex is an active and selective catalyst in partial cyclohexane oxidation.