A new oxidovanadium(Ⅳ) Schiff base complex containing asymmetric tetradentate ONN0O0Schiff base ligand:Synthesis,characterization,crystal structure determination,thermal study and catalytic activity

After synthesis of an asymmetric tetradentate ONN0O0 Schiff base ligand(H2L) followed by reaction of the synthesized H2 L with an equimolar mixture of methanolic solutions of the VO(acac)2, a new oxidovanadium(IV) Schiff base complex(VOL) was synthesized. The Schiff base ligand and its complex were characterized by FT-IR and UV–vis spectra and C, H, N analysis. The crystal structure of VOL was also determined by single crystal X-ray analysis. The VOL complex crystallizes in monoclinic space group Cc. The Schiff base ligand acts as a tetradentate ligand through its two iminic nitrogens and two phenolic and acetylacetonate oxygens. Thermogravimetric analysis of the VOL showed that it decomposes in two steps and converts to mixed vanadium oxides at 477 8C. In addition, thermal decomposition of the VOL complex in air at 660 8C leads to formation of V2O5 nanoparticles with the average size estimated from XRD 49 nm. The catalytic activity of the VOL complex was investigated in the epoxidation reaction and different reaction parameters were optimized. The results showed that the cyclic alkenes were efficiently converted to the corresponding epoxides, whereas the VOL did not appreciably convert the linear alkenes.