Nanoparticles silica anchored Cu(II) and V(IV) scorpionate complexes for selective catalysis of cyclohexane oxidation

Silica nanoparticles (SiNPs) with the average size of 8.4 nm have been synthesized and functionalized with the reaction of Cl-sulfonylphenylethyl tri-methoxysilane. These functionalized SiNPs have been anchored in scorpionate compounds i.e., [CuCl2{HOCH2C(Pz)(3)}], [V=OCl2{HOCH2C(Pz)(3)}], and [V(acac) {HOCH2C(Pz)(3)}] as hybrid nano-catalysts. The presence of metal compound over support was confirmed with FIR, EPR, TGA, TEM, XRD, MS, and TEM-EDS. These catalysts have produced remarkable high TONs ca. 1216-2607 with yields 13.7-27.3% for the selective oxidation of cyclohexane (Cy-hx) with molecular oxygen under relatively mild conditions. Very high about 95% products selectivity of Cy = O and Cy-OH was also attained. The TGA analysis indicates that all the catalysts were thermally stable under operating reaction temperature and reusable up to five more cycles. (C) 2015 Elsevier B.V. All rights reserved.