Wydział Chemii

Neda Heydari

Rahman Bikas

Maryam Shaterian

Marta S. Krawczyk

Tadeusz Lis

2023

Applied Organometallic Chemistry

37

e6976/1-e6976/18

10.1002/aoc.6976

Naukowa

Angielski

Artykuł

Vanadium coordination compounds, [VO₂L]·(CH₃OH) (1a and 1b), were prepared from the reaction of tridentate hydrazone ligand, [HL=(E)-4-amino-N′-(1-(pyridin-2-ylethylidene)benzohydrazide] with NH₄VO₃ and V₂O₅, respectively. These compounds were characterized by various analytical methods, and the structures of 1a and 1b were determined by single crystal X-ray analysis which indicated that they have the same composition but crystallized in different unit cells and can be considered as polymorphs. The silica-supported catalyst (Si-VO₂L) was obtained by immobilization of 1 on the surface of silica using propionyl chloride-functionalized silica gel. Si-VO₂L was characterized by thermal gravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared (FT-IR) spectroscopy, diffuse-reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and X-ray diffraction analysis (XRD) and was employed as heterogeneous catalyst in the oxidation of styrene derivatives, and aqueous H₂O₂ was used as the green oxidant. Si-VO₂L was recovered several times, and characterized by various analytical methods. The results indicated its high stability. The effects of parameters such as temperature, the ratio of reagents, and nature of solvent on selectivity and activity of Si-VO₂L were investigated. The results indicated that both of the steric and electronic effects of the substituents on the phenyl ring of styrene can affect the selectivity and activity of the products. Electron withdrawing groups decrease the activity of the substrate and electron donating groups increase the activity.

http://dx.doi.org/10.1002/aoc.6976

onlinelibrary.wiley.com