Schiff base complexes of methyltrioxorhenium (VII): Synthesis and catalytic application

Schiff bases coordinate smoothly with methyltrioxorhenium (MTO) to yield the corresponding MTO–Schiff base adducts, which were characterized by IR, NMR and elemental analysis. The X-ray structure of one of the complexes was exemplary determined. The compounds were used as catalysts for cyclooctene epoxidation in ionic liquids with UHP (urea hydrogen peroxide adduct) as oxidant at room temperature. The results show that (N-salicylidene)aniline derived Schiff base complexes of MTO displayed higher catalytic activity and selectivity than di-nitrogen Schiff base complexes of MTO. No diol byproduct formation is observed.