An oxidovanadium(IV) complex with 4,4′-di-tert-butyl-2,2′-bipyridine ligand: Synthesis, structure and catalyzed cyclooctene epoxidation

The interaction of vanadium(III) chloride (VCl₃) with 4,4′-di-tert-butyl-2,2′-bipyridine (dbbpy) in air resulted in the monomeric oxidovanadium(IV) complex [VOCl₂(dbbpy)(H₂O)] (1) in high yield. The complex was characterized by IR and EPR spectroscopies, by elemental analysis, and by single crystal X-ray diffraction analysis. The vanadium atom has a distorted octahedral coordination environment. The EPR spectrum of 1 in CH₂Cl₂ demonstrates an eight-line signal typical of vanadium(IV) with a d¹ electronic configuration. Complex 1 exhibits catalytic activity in the cyclooctene oxidation with tert-butyl hydroperoxide (TBHP) in CHCl₃. Detailed EPR, NMR and GC–MS studies of the reaction revealed a few mechanistic details and the nature of by-products that are generated by involvement of the chloroform solvent.