Synthesis, Structure Characterization And Efficient Catalysis For Tetralin Oxidation Of Cu(Ⅱ) Complexes

Complexes c1 and c2 were synthesized through the reaction of 2-aminomethyl pyridine (s1) with CuCl₂·2H2O by changing the metal/ligand ratio. Complex c3 was synthesized by the combination of CuCl₂·2H2O with tri-nitrogen ligand (s2) which was obtained through a reduction reaction with 2-aminomethyl pyridine and 2-pyridinecarboxaldehyde as starting materials and NaBH4 as reducing agent. Structures of the complexes were characterized by 1H NMR, IR, UV, elemental analysis and X-ray diffraction method. The results revealed that complexes c1 and c3 displayed distorted tetragonal pyramid. Complex c2 exhibited an octahedral geometry.Complex c1 was used as catalyst in the oxidation of tetralin to tetralon with tert-butyl hydroperoxide as an oxidant. The effects of solvent, reaction temperature, oxidant and material ratio were investigated. An optimum condition was obtained (acetonitrile 10 mL, catalyst 0.045 mmol, tetralin 4.5 mmol, tert-butyl hydroperoxide 22.5 mmol, T = 50℃). Under this reaction condition, complexes c2 and c3 were evaluated as catalysts in the tetralin oxidation compared with c1. It was found that the catalytic performances of the catalysts depended on their structures. The purpose of controlling the conversion of the reaction and the selectivity of the target product could be carried out by changing ligand.In the second part, esoporous molecular sieve MCM-41 was functionalized by a multi-step grafting method. Then CuCl₂ was assembled in MCM-41 through the coordination of CuCl₂ with the supported functional groups, which afforded two novel heterogenized CuCl₂ catalysts. The resulting catalysts were characterized by FT-IR, UV-Vis, AAS, XRD and nitrogen adsorption, and were evaluated in the tetralin oxidation with tert-butyl hydroperoxide as an oxidant. The heterogenized catalysts performed well at the first time but poor in the case of recycle run.