Copper Functionalized Metal-Organic Framework as Catalyst for Oxidant-Controlled Partial Oxidation of Cyclohexene

Microwave irradiation was exploited for the facile, one-step functionalization of Cu(acac)2 to -NH2 pendant groups of MIL-53(Al)-NH2, a metal-organic framework material, under mild reaction condition and short reaction time. PXRD, XPS, XAS, and EPR spectroscopies were used to investigate the structure and chemical nature of the copper species on the framework. The copper center exists in +2 oxidation state with a square planar geometry and NO3 coordination environment. The copper complex is anchored to the framework via imine bond formation. This copper functionalized MIL-53(Al)-NH2 or MIL-53[Cu] was employed in the catalytic oxidation of olefins using molecular oxygen (O2) or tert-butyl hydroperoxide (TBHP) as oxidants. The chemoselectivities of the oxidation products depend on types of oxidant and substrate. When O2 was used as the oxidant and isobutyraldehyde as the co-oxidant in the oxidation of cyclohexene with MIL-53[Cu], cyclohexene oxide was the major product. However, when TBHP was employed as the oxidant, 2-cyclohexen-1-one was the major product. Furthermore, the catalyst can be reused for at least three times without a significant loss in activities.

from #MedicinebyAlexandrosSfakianakis via xlomafota13 on Inoreader http://ift.tt/2AbHi2i
via IFTTT