Methyl Maltolate and Ethyl Maltolate Coordinated Oxidovanadium(V) Complexes with N'-(2-Hydroxy-5-methylbenzylidene)-4-trifluoromethylbenzohydrazide: Synthesis, Crystal Structures and Catalytic Epoxidation Property.

A mononuclear methyl maltolate (Hmm) coordinated oxidovanadium(V) complex [VOL1(mm)] (1), and a mononuclear ethyl maltolate (Hem) coordinated oxidovanadium(V) complex [VOL2(em)] (2), where L1 and L2 are the dianionic form of N'-(2-hydroxy-5-methylbenzylidene)-3-trifluoromethylbenzohydrazide (H2L1) and N'-(2-hydroxy-5-methylbenzylidene)-4-trifluoromethylbenzohydrazide (H2L2), respectively, have been prepared. The hydrazones and the complexes were characterized by elemental analysis, FT-IR and UV-Vis spectra. Structures of H2L1 and the two complexes were further characterized by single crystal X-ray diffraction. The two complexes have similar structures, with the V atoms in octahedral coordination. The hydrazones behave as ONO tridentate ligands with the V atoms. Both complexes have interesting properties on the catalytic epoxidation of cyclooctene.