Synthesis And Property Characterization Of Uranyl Organic Framework Complex Based On Semirigid Ligand Of Tricarboxylic Acid

Series of novel uranyl Mononuclear coordination polymers[?CH₃?₂NH₂]UO₂?BTPCA??1?,[?CH₃?₂NH₂]UO₂?BTPCA??2?,[?CH₃?₂NH₂]₂[UO₂?BTPCA?][UO₂?BTPCA?]·?H₂O?_5.5?3?,[?CH₃?₂NH₂]₂?UO₂?₂?BTPCA?₂·?H₂O?₃?4?,[?CH₃?₂NH₂]UO₂?BTPCA??5?,were synthesized by the utilization of semirigid ligand 1,1',1''-?benzene-1,3,5-triyl?tripiperidine-4-carboxylic acid?H₃BTPCA?and uranyl nitrate at solvothermal conditions.Single-crystal X-ray diffraction analysis reveals that the five compounds share the similar structure composition and local coordination mode to the exclusion of disordered water or DMF molecules.Each UO₂?COO?₃^-motif is connected to six neighboring units through three BTPCA^3-ligands,generating an infinite uranyl honeycomb?6,3?net.The structures of all the five compounds consist of 2D honeycomb nets of various degrees of distortions,which are induced by the flexibility of piperidine rings.The dimethylamine cations and solvent molecules fill in the space between layers.Therefore,these five compounds are isomers from a broad sense.Notably,both compounds 3 and 4 possess 2-fold interpenetrated structures.For compound 5,the distance between the neighboring 2D honeycomb nets is7.253?.This is the largest distance between the 2D honeycomb nets in uranyl-based coordination polymers,to the best of our knowledge.In addition,compounds 1,2 and 4 are characterized by Infrared spectroscopy?IR?,thermogravimetric analysis?TG?,powder X-ray diffraction?PXRD?and luminescence properties.We also acquire two kinds of novel uranyl Tetranuclear coordination polymers:[UO₂?BTPCA??CH₃?₂OH]?6?,[UO₂?BTPCA??CH₃?₂OH]₂?7?.Due to the flexibility of piperidine rings of H₃BTPCA ligand,We acquire different uranyl coordination polymers in the aspect of dimensionality.Therein compound 6 is two-dimensional and uranyl Tetranuclear coordination polymers,but compound 7 is three-dimensional and uranyl Tetranuclear coordination polymers.Using semirigid ligand and charging experiment condition can make coordination mode more versatile and be beneficial to synthetize uranyl coordination polymers of high dimensionality.In addition,compounds 6 and 7 are also characterized by Infrared spectroscopy?IR?,thermogravimetric analysis?TG?,powder X-ray diffraction?PXRD?and luminescence properties.