Self-Assembly of a U(VI)-Containing Polytungstate Tetramer with Lewis Acid-Base Catalytic Activity for a Dehydration Condensation Reaction
- 2 November 2022
- journal article
- research article
- Published by American Chemical Society (ACS) in Inorganic Chemistry
- Vol. 61 (50) , 20358-20364
Abstract
A novel U(VI)-containing polytungstate (U-POW) tetramer, {K1.37Na26.63[K2(UO2)4Cl0.5(OH)5.5(γ-SiW10O36)4]}·ca66H2O (U4), was synthesized using the Keggin-type precursor [γ-SiW10O36]8- and UO2(NO3)2. U4 was further characterized by single-crystal X-ray diffraction, FT-IR, Raman spectroscopy, solid-state diffuse reflection spectroscopy, ICP-OES, ESI-MS, TGA, and PXRD. The central {K2(UO2)4Cl0.5(OH)5.5} chromophore was constructed dexterously from four uranyl, four halves of K ions, 5.5 bridging μ2-OH, and disordered Cl ions, and was further stabilized by four {γ-SiW10} moieties to construct the tetramer [K2(UO2)4Cl0.5(OH)5.5(γ-SiW10O36)4]28-. Notably, U4 could work as an effective bifunctional Lewis acid-base catalyst for the synthesis of pyrazoles via the condensation of hydrazines with 1,3-diketones under mild conditions, which is attributed to the synergetic effect of the Lewis acidity of U(VI) and the Lewis basicity of {γ-SiW10}.Keywords
Funding Information
- East China Institute of Technology (DHBK2019267)
- National Natural Science Foundation of China (22001034)
- Natural Science Foundation of Jiangxi Province (20212BAB213001)
- Guangdong Provincial Key Lab of Green Chemical Product Technology, South China University of Technology (GC202116)
- Jiangxi Province Key Laboratory of Synthetic Chemistry, East China University of Technology (JXSC202008)
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