Synthesis, structure and catalytic activity of new oxovanadium(V) complexes with deferiprone and N,N-donor ligands

Facile synthesis and structural characterization of two new dioxovanadium(V) complexes containing deferiprone and diimine as ligands are described. The complexes displayed remarkable catalytic efficiency in the selective epoxidation of styrene with H2O2, at room temperature under organic solvent-free condition. The developed catalytic strategy is simple, high yielding, and eco-compatible. [Display omitted] •Synthesis of new dioxovanadium(V) complexes with deferiprone and diimine ligands.•Structural characterization of the complexes with single crystal X-ray diffraction.•Complexes efficiently catalyzed selective epoxidation of styrene with 30% H2O2.•Styrene epoxidation occurred with > 99% selectivity at room temperature in absence of organic solvent.•The catalysts are recyclable for multiple cycles of oxidation. A pair of new water-soluble oxovanadium(V) complexes comprising of deferiprone (def) and N,N-donor ligands, 2,2ʹ-bipyridine (bpy) or 1,10-phenanthroline (phen), [VO2(def)(bpy)]⋅H2O (1) and [VO2(def)(phen)]⋅4H2O (2) were synthesized. The complexes were characterized by elemental analysis, spectral studies and single crystal X-ray diffraction analysis. The X-ray crystal structures of 1 and 2 reveal that both the complexes possess distorted octahedral coordination geometries with O4N2 coordination sphere around the vanadium center, and the deprotonated deferiprone occupying the equatorial plane. The complexes 1 and 2 efficiently catalyzed selective epoxidation of styrene with 30% H2O2 under ecologically sustainable organic solvent-free conditions, at ambient temperature. The catalysts afforded good styrene conversion and high TON value along with excellent epoxide selectivity (>99%). Recyclability of the catalysts at least up to three consecutive cycles without significant alteration in activity or selectivity, is an additional remarkable feature of the developed catalytic protocol.