摘要
A novel uranyl-containing polytungstate,{K_(4.2)Na_(18.9)H_(0.9)(H_(2)O)_(20)[K_(4)(UO_(2))_(3)(H_(2)O)_(6)(α-SiW_(9)O_(34))(γ-SiW_(10)O_(36))_(3)]}·ca.16H_(2)O(U_(3)),was synthesized using the Keggin-type precursor[γ-SiW_(10)O_(36)]^(8-)({γ-SiW_(10)})and UO_(2)(OAc)_(2) and was further characterized by single-crystal X-ray diffraction and various techniques.Single crystal X-ray diffraction analysis showed a quadrahedron-like structure of U_(3) with interesting tarot-like(top view)and crown-like(side view)views,among which one central{K_(4)(UO_(2))_(3)(H_(2)O)_(3)}cluster was surrounded by one{α-SiW_(9)}and three{γ-SiW_(10)}building units.In addition,a more significant aspect is that U_(3) shows good catalytic activity in the dehydration condensation of aldehydes,acetoacetates,and urea to green synthesize dihydropyrimidin-2(1H)-ones.The advantages of this transformation include solvent-free conditions,water as the sole by-product,available starting materials,good compatibility,and operational simplicity.
基金
supported by the National Natural Science Foundation of China(22001034)
the Jiangxi Provincial Natural Science Foundation(20212BAB213001)
the Natural Science Foundation of Guangxi(2022GXNSFGA035003).
