Synthesis, Characterization and X-Ray Crystal Structures of Two Schiff Base Copper(II) Complexes with Catalytic Property

Two new copper(II) complexes, [Cu₂(L^a)₂(OAc)₂]·2H₂O (1) and [Cu(L^b)₂] (2), where L^a and L^b are the deprotonated monoanionic form of 5-bromo-2-(ethylaminoethylimino)methyl)phenol (HL^a) and 5-bromo-2-cyclohexyliminomethylphenol (HL^b), respectively, have been synthesized and characterized by elemental analysis, infrared and electronic spectroscopy. Structures of both complexes were further determined by single crystal X-ray diffraction. Complexes 1 and 2 were synthesized from copper acetate with HL^a and HL^b, respectively in methanol. The Cu atoms in complex 1 are in octahedral coordination, while that in 2 is in square planar coordination. The two complexes have high catalytic property for the epoxidation of styrene, with conversions over 90% and selectivity over 85%.