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

• Functionalized nanoperticles SiNPs support preparation.
• Immobilized tri(pyrazolyl) ethanol Cu and V-complexes as supported catalyst.
• Nano-catalysts test in gas–liquid phase O2 oxidation of cyclohexane.
• High catalytic TONs and selective product.

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}], [VOCl2{HOCH2C(pz)3}], and [V(acac) {HOCH2C(pz)3}] as hybrid nano-catalysts. The presence of metal compound over support was confirmed with FTIR, EPR, TGA, TEM, XRD, AAS, 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.

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