Synthesis, characterization, DFT calculations, and catalytic epoxidation of two oxovanadium(IV) Schiff base complexes

Authors : Asha WADY, Mohammed KHALİD, Mohammed ALOTAİBİ, Yusuf AHMED

Pages : 163-208

Doi:10.18596/jotcsa.1008578

View : 9 | Download : 5

Publication Date : 2022-02-28

Article Type : Research Paper

Abstract :The present paper reports the synthesis, characterization, and DFT calculations of two oxovanadium insert ignore into journalissuearticles values(IV); Schiff base complexes symbolized as VOL1 and VOL2, which prepared by the reaction of bivalent tridentate Schiff base ligands insert ignore into journalissuearticles values(E);-2-insert ignore into journalissuearticles values(insert ignore into journalissuearticles values(5-chloro-2-hydroxybenzylidene);amino);acetic acid and insert ignore into journalissuearticles values(E);-2-insert ignore into journalissuearticles values(insert ignore into journalissuearticles values(2-hydoxy-5-nitrobenzylidene);amino);acetic acid and VOinsert ignore into journalissuearticles values(acac);2 as vanadium source. The Schiff base ligands and its oxovanadium insert ignore into journalissuearticles values(IV); complexes were characterized by the elemental analysis insert ignore into journalissuearticles values(C, H, N);, FTIR, 1H NMR and 13C NMR, DFT calculations were performed to derive some of their molecular properties. Schiff base ligands coordinated to vanadium center via nitrogen from the azomethine group and one oxygen from the hydroxyl attached to the benzene ring and one oxygen from hydroxyl of carboxyl group. The catalytic activity of the two complexes were tested against cyclooctene and found that both complexes were highly effective and selective in optimized conditions when used as cyclooctene epoxidation catalysts with the conversion percentage of 91.85% insert ignore into journalissuearticles values(with VOL1); and 87.40% insert ignore into journalissuearticles values(with VOL2); at 78 °C within a period of ten hours. To understand the structural properties of the two complexes, the two complexes were well optimized at B3LYP/6-31Ginsert ignore into journalissuearticles values(d,p); level of theory, structural parameters such as electron affinity, global electrophilicity, global hardness, electronegativity, ionization potential, and electron chemical potential based on HOMO and LUMO energy values were calculated.
Keywords : Schiff base, DFT calculations, Epoxidation catalysis, Geometry optimizations, Oxovanadium complexes, Global chemical reactivity