A Metal‐Organic Complex Constructed from Co(II), Azo‐amide‐pyridyl and Benzenetricarboxylate Mixed Ligands: Efficient Catalysis for Selective Oxidation of Benzyl Alcohols to Benzyl Acids

Abstract

AbstractBy using one‐step hydrothermal synthesis, a novel metal‐organic complex containing Co(II), the azo‐amide‐pyridyl ligand (E)‐4,4′‐(diazene‐1,2‐diyl)bis(N‐(pyridin‐3‐yl)benzamide (DABA) and benzenetricarboxylate was synthesized, with a molecular formula of [Co2(DABA)0.5(MTC)(μ3‐OH)(H2O)2] ⋅ 2H2O (namely 1, DABA=(E)‐4,4′‐(diazene‐1,2‐diyl)bis(N‐(pyridin‐3‐yl)benzamide, H3MTC=1,2,4‐benzenetricarboxylic acid) which was characterized by single crystal X‐ray diffraction, PXRD, IR spectroscopy, TGA, and XPS. In the structure of complex 1, tetranuclear Co(II) clusters were connected by MTC to form a 2D bilayer structure and further constructed a 3D structure with DABA ligand. Complex 1 was used as an efficient heterogeneous catalyst for the oxidation of benzyl alcohol, and the conversion rate of benzyl alcohol reached 98.6 % and the selectivity of benzoic acid reached 94.8 %. In addition, complex 1 can be reused 5 times without significant loss of activity. The oxidation of benzyl alcohol with different substituents also showed satisfactory conversion and selectivity, indicating that complex 1 had good catalytic performance.