CuII complexes bearing the 2,2,2-tris(1-pyrazolyl)ethanol or 2,2,2-tris(1-pyrazolyl)ethyl methanesulfonate scorpionates. X-Ray structural characterization and application in the mild catalytic peroxidative oxidation of cyclohexane

摘要: Reactions between CuCl2 and the functionalized scorpionate 2,2,2-tris(1-pyrazolyl)ethanol HOCH2C(pz)31 (pz = pyrazolyl) or 2,2,2-tris(1-pyrazolyl)ethyl methanesulfonate CH3SO2OCH2C(pz)32 yield corresponding water soluble CuII complexes [CuCl2{HOCH2C(pz)3}] 3 [CuCl2{CH3SO2OCH2C(pz)3}]24. In ligand shows typical N,N,N-coordination mode, whereas in dinuclear complex 4 it binds metal as a bidentate species. Compounds 1-4 have been characterized by IR, far-IR, elemental analysis (for 2-4) single crystal X-ray diffraction. The new are shown to act catalyst precursors for peroxidative oxidation of cyclohexane cyclohexanol (main product) cyclohexanone, under mild conditions (at room temperature using an aqueous solution H2O2) reaching TON values up 186 NCMe/H2O. Their hydrosolubility allows them operate also pure media (without any organic solvent, although less effectively), rare feature significance towards green alkane process.