An Zhixuan, Li Xiaohui, Zhang Zhong, Wang Xiuli
College of Chemistry and Materials Engineering, Bohai University, Jinzhou 121013, P. R. China.
Inorg Chem. 2024 Oct 21;63(42):19956-19963. doi: 10.1021/acs.inorgchem.4c03482. Epub 2024 Oct 10.
The design and synthesis of efficient and environmentally friendly heterogeneous catalysts for the oxidation of phenols to benzoquinones are of great significance. Considering the highly catalytic activity of mixed-valence metals and polyoxometalates (POMs), a three-dimensional polyoxometalate-based metal-organic complex with mixed-valence Cu/Cu, [CuCu(pyca)(OH)(PMoOCu)(HO)]·3.5HO (, Hpyca = 2-pyrazinecarboxylic acid) has been successfully synthesized under solvothermal conditions. Surprisingly, complex not only combines the desired mixed-valent Cu/Cu and POM sites but also contains a rare double Cu-capped POM structure. Due to the ternary synergistic effect of Cu, Cu, and POM, complex exhibits excellent catalytic activity in the oxidation reaction of 2,3,6-trimethylphenol to the corresponding -benzoquinone. The conversion and selectivity can reach 98 and 99% within 5 min, respectively, and the turnover frequency (TOF) value is as high as 8167 h, which is superior to most catalysts.
设计和合成用于将苯酚氧化为苯醌的高效且环境友好的多相催化剂具有重要意义。考虑到混合价金属和多金属氧酸盐（POMs）具有高催化活性，一种具有混合价Cu/Cu的三维基于多金属氧酸盐的金属有机配合物，即[CuCu(pyca)(OH)(PMoOCu)(H₂O)]·3.5H₂O（Hpyca = 2-吡嗪羧酸）已在溶剂热条件下成功合成。令人惊讶的是，配合物不仅结合了所需的混合价Cu/Cu和POM位点，还包含罕见的双Cu封端POM结构。由于Cu、Cu和POM的三元协同效应，配合物在将2,3,6-三甲基苯酚氧化为相应的对苯醌的反应中表现出优异的催化活性。转化率和选择性在5分钟内分别可达98%和99%，周转频率（TOF）值高达8167 h⁻¹，优于大多数催化剂。
