3D Uranyl Organic Frameworks Supported by Rigid Octadentate Carboxylate Ligand: Synthesis, Structure Diversity, and Luminescence Properties

• Published in: Chemistry : a European journal 2021-07, Vol.27 (40), p.10313-10322
• Main Authors: Wu, Dai, Mo, Xiu‐Fang, He, Piao, Li, Hai‐Ru, Yi, Xiao‐Yi, Liu, Chao
• Format: Article
• Language: English
• Subjects: Benzene; Carboxylates; Chemistry; Crystal structure; Dimers; fluorescence; Imidazole; Ligands; Luminescence; metal organic frameworks; Molecular structure; Optical properties; Polyoxometallates; Single crystals; topological structure; Transition metals; Uranium dioxide; uranyl compound; Zinc
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202100099

Seven three dimensional (3D) uranyl organic frameworks (UOFs), formulated as [NH4][(UO2)3(HTTDS)(H2O)] (1), [(UO2)4(HTTDS)2](HIM)6 (2, IM=imidazole), [(UO2)4(TTDS)(H2O)2(Phen)2] (3, Phen=1,10‐phenanthroline), [Zn(H2O)4]0.5[(UO2)3(HTTDS)(H2O)4] (4), and {(UO2)2[Zn(H2O)3]2(TTDS)} (5), {Zn(UO2)2(H2O)(Dib)0.5(HDib)(HTTDS)} (6, Dib=1,4‐di(1H‐imidazol‐1‐yl)benzene) and [Na]{(UO2)4[Cu3(u3‐OH)(H2O)7](TTDS)2} (7) have been hydrothermally prepared using a rigid octadentate carboxylate ligand, tetrakis(3,5‐dicarboxyphenyl)silicon(H8TTDS). These UOFs have different 3D self‐assembled structures as a function of co‐ligands, structure‐directing agents and transition metals. The structure of 1 has an infinite ribbon formed by the UO7 pentagonal bipyramid bridged by carboxylate groups. With further introduction of auxiliary N‐donor ligands, different structure of 2 and 3 are formed, in 2 the imidazole serves as space filler, while in 3 the Phen are bound to [UO2]2+ units as co‐ligands. The second metal centers were introduced in the syntheses of 4–7, and in all cases, they are part of the final structures, either as a counterion (4) or as a component of framework (5−7). Interesting, in 7, a rare polyoxometalate [Cu3(μ3‐OH)O7(O2CR)4] cluster was found in the structure. It acts as an inorganic building unit together with the dimer [(UO2)2(O2CR)4] unit. Those uranyl carboxylates were sufficiently determined by single crystal X‐ray diffraction, and their topological structures and luminescence properties were analyzed in detail. Seven 3D uranyl organic frameworks have been hydrothermally prepared using a rigid octadentate carboxylate linker. These UOFs have diverse 3D self‐assembled architectures as a function of pH, co‐ligands, structure‐directing agents and transition metals.