화학공학소재연구정보센터
Inorganic Chemistry, Vol.57, No.8, 4492-4501, 2018
Semirigid Tripodal Ligand Based Uranyl Coordination Polymer Isomers Featuring 2D Honeycomb Nets
We report five novel uranyl coordination polymers, [(CH3)(2)NF[(2)]UO2-(BTPCA) (1), [(CH3)(2)NH2]UO2(BTPCA) (2), [(CH3)(2)NH2](2)[UO2(BTPCA)]-[UO2(BTPCA)]center dot(H2O)(5.5) (3), [(CH3)(2)NH2](2)(UO2)(2)(BTPCA)(2)center dot(H2O)(3) (4), and [(CH3)(2)NH2]UO2(BTPCA) (5), by the utilization of semirigid ligand 1,1',1''-(benzene-1,3,5-triyl)tripiperidine-4-carboxylic acid (H(3)BTPCA) and uranyl nitrate through solvothermal reactions. Single-crystal X-ray diffraction analysis reveals that the five compounds share a 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 in 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 is 7.253 (A) over bar. 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 also characterized by infrared spectroscopy (IR), thermogravimetric analysis (TG), powder X-ray diffraction (PXRD), and luminescence properties.