Rare cis-Dioxido Uranyl Framework Crystalline Complexes: Synthesis, Structure, Characterization and Properties

The trans-dioxido uranyl frameworks named as [(UO2)(Aip)(DMA)] (1), H[(UO2)(Aib)(3)] (2) and rare cis-dioxido [(UO2)Co(Suc)(2)(H2O)(4)] (3), and [(UO2)Ni(Suc)(2)(H2O)(4)] (4) have been synthesized, which based on 5-aminoisophthalic acid (H(2)Aip), 3-aminobenzoic acid (HAib), and succinic acid (H(2)Suc) as ligands. They were characterized by Fourier Transform Infrared spectra, UV-vis absorption spectra, single-crystal X-ray diffraction, powder X-ray diffraction and thermogravimetry analysis. It was found that uranium ion of the complex 1 is in the pentagonal bipyramidal coordination environment, while those of the complexes 2-4 are in the hexagonal bipyramidal coordination environment. Complexes 1, 3, and 4 are 3D network structures, 2 is a discrete structure. In particular, geometry of O=U=O for 1 and 2 are trans, ones for 3 and 4 are cis. The highest removal rate of methylene blue was almost to 96 % by complex 1 as an adsorbent, which illustrates that potential application on dye adsorption.

Automated summary

Different trans-dioxido uranyl frameworks were synthesized and characterized, showing distinct structures and coordination environments. Complex 1 exhibited the highest removal rate of methylene blue, indicating its potential for dye adsorption applications.