Molecular Design,Syntheses,Structural Characterizations And Properties Of Actinide Complexes Based On Rigid And Flexible Aromatic Polycarboxylate Ligands

In recent years,the coordination chemistry of uranyl-bearing hybrid materials has already attracted extensive attention from numerous researchers not only due to the diverse chemical compositions and architectures of uranyl-organic frameworks(UOFs),but also a wide range of potential applications in photochemistry,magnetism,and catalysis.In this thesis,six novel microporous uranyl complexes have been designed and synthesized by utilizing a series of aromatic polycarboxylate ligands.The samples are characterized using X-ray single-crystal diffraction,elemental analyses,infrared spectra,UV-vis spectra,TG and powder X-ray diffraction.Furthermore,the physicochemical properties are investigated in detail for understanding the relationship between the structures and properties.The main work includes two parts as follows:1.Three UOFs have been obtained by the hydrothermal reaction based on the flexible 1,3,5-triazine-2,4,6-triamine hexaacetic acid(H6TTHA).These complexes exhibit three distinct 3D self-assembly architectures as a function of pH by single-crystal structural analysis.Surprisingly,all of the coordination modes of the ligand H6TTHA in this work are firstly discovered.The photoluminescent(PL)results show that these complexes all exhibit characteristic emission of(UO2)2+ and display high-sensitivity luminescent sensing functions for nitrobenzene,which may be used for nitrobenzene sensing application.In addition,the surface photovoltage spectra show that complexes 1-3 possess photovoltage characteristic,which could be applied as extended p-type semiconductors.2.Three other porous UOFs have been designed and synthesized under solvothermal and hydrothermal reaction conditions based on a series of aromatic polycarboxylate ligands,5-((4-carboxybenzyl)oxy)isophthalic acid(H3L1),4,4'-oxydiphthalic acid(H4L2),and 4,4'-((6-chloro-1,3,5-triazine-2,4-diyl)bis(azanediyl))dibenzoic acid(H2L3).The X-ray crystal structure analysis reveals that complex 4 and complexes 5-6 possess the anionic and neutral 2D framework structures,respectively.Complex 6 could be further extended to a 3D supramolecular network through the hydrogen-bond interaction.We investigate the main factors on the uranyl hydrolysis systematically and discussed the in situ reaction mechanism in 6 in detail.For photoluminescence,complexes 5 and 6 exhibit characteristic emission of(UO2)2+,and 5 further exhibits the unusual characteristic five-peak of(UO2)2+ influenced by organic solvents polarity and conjugacy.The surface photovoltage spectra show that only complexes 5 and 6 can behave as potential p-type semiconductors.In addition,the experimental results of dye absorption and separation show that the anionic framework 4 displays the remarkable advantages for selective adsorption towards cationic MB dye by comparison with the neutral ones 5 and 6.{[(U02)2(H2TTHA)(H20)]·4,4'-bipy~2H2O}n(1){[(UO2)3(TTHA)(H20 3]}n(2){[(U02)5(TTHA)(HTTHA)(H2O)3]·H3O}n(3){[(CH3)2NH2]2[(U02)(L1)]2·H2O}n(4){[(U02)(?2-OH)(?3-OH)(L2)2(H20)3]}n(5){[(U02)4(?3-OH)2(L3*)3 2H20}n(6)Note:H2L3*=4,4'-((6-(dimethylamino)-1,3,5-triazine-2,4-diyl)bis(azanediyl))dibenzoic acid;4,4'-bipy=4,4'-bipyridine...