Synthesis, single crystal structures and efficient catalysis for tetralin oxidation of two novel complexes of Cu(II) with 2-aminomethyl pyridine

Two novel Cu(II) complexes were synthesized through the reaction of 2-aminomethyl pyridine (AMP) with CuCl2·2H2O by changing the metal/ligand ratio. Their structures were thoroughly characterized by FT-IR, elemental analysis and X-ray diffraction method. The results revealed that complex 1 [Cu(AMP)Cl2] consists of isolated binuclear molecules unit and displays distorted tetragonal pyramid. Complex 2 [Cu(AMP)2(H2O)2]Cl2 exhibits a octahedral geometry. The complexes were both evaluated as catalysts in the tetralin oxidation with TBHP as oxidant. Complex 1 showed high catalytic activity and selectivity towards α-tetralone under mild conditions. Thus, under the optimized conditions (acetonitrile 10 ml, catalyst 0.045 mmol, tetralin 4.5 mmol, 65% TBHP 22.5 mmol, T = 50 °C), the conversion of tetralin reached 89% with a selectivity of 71% towards α-tetralone. Compared with complex 1, complex 2 displayed low catalytic activity mainly due to the strong steric hindrance from the two coordinated 2-aminomethyl pyridine molecules.

Two novel Cu(II) complexes were synthesized and evaluated as catalysts in the tetralin oxidation with TBHP as oxidant. Complex 1 showed good performances in the catalytic reaction.Figure optionsDownload high-quality image (93 K)Download as PowerPoint slideResearch highlights▶ Two novel Cu(II) complexes were synthesized and characterized thoroughly. ▶ Complex 1 showed high activity and selectivity in the tetralin oxidation by TBHP. ▶ Their catalysis in tetralin oxidation are related to the structure of the complexes.