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

Abstract

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.