Synthesis of superparamagnetic carbon nanotubes immobilized Pt and Pd pincer complexes: highly active and selective catalysts towards cyclohexane oxidation with dioxygen.

Single-walled carbon nanotubes (SWNTs) with Ni/Co have been prepared using an arc discharge technique and Ni/Co–carbon composite rods in an inert atmosphere and were surface modified using 3-aminophenyl trimethoxysilane. These NH2-functionalized magnetic carbon nanotubes have been used as a novel support for Pd(II) and Pt(II) pincer complexes immobilized as magnetic nano-catalysts. The morphology of the support and the catalysts have been characterized by IR, EPR, SEM, TGA, TEM, XRD, AAS and EDS analysis. These magnetic nano-catalysts have been tested on the industrially important cyclohexane (Cy-hx) oxidation with O2 and significantly high TONs of 1678 to 1946 were achieved under solvent free and relatively mild conditions. The SWNTs/Pd catalyst provided the best conversion, 22.7%, but the SWNTs/Pt system also provided a good conversion of 20.7%.