| Summary: | 碩士 === 國立中正大學 === 化學暨生物化學研究所 === 103 === The goal of this study was to develop a self-assembly synthetic strategy for preparing coordination polymers using two ligands: orotic acid and urocanic acid. The synthetic method, structures and some properties of the products were investigated.
Because both of these ligands contain carboxylate, imide and imidazole functional groups, respectively, they offer a very rich coordination chemistry. Thus, the numerous binding modes of the ligands can be expected to give rise to materials with drastically differing structures.
The reaction of CaCl2•H2O with H2Or at 80 ℃ resulted in the formation of a 3D coordination polymer {[Ca(Or)(H2O)]}n (1); and the reaction of Co(NO3)2•6H2O with H2Or and 4,4′-bipyridine at 50 ℃ resulted in the formation of a 0D monomer
{[Co2(Or)2(bpy)(H2O)6]•H2O} (2).
The reaction of Cd(NO3)2•4H2O with HIA and H2bdc at 80 ℃ gave a 3D coordination polymer {[Cd(IA)(bdc)0.5(DMF)]}n (3), and, under the same conditions, but changing the metal ions to Co(NO3)2•6H2O and Ni(NO3)2•6H2O, two isostructure monomers {[Co(IA)2(H2O)4]} (4) and {[Ni(IA)2(H2O)4]} (5) are produced. The reaction of Zn(NO3)2•6H2O with HIA and KCl at 80 ℃ for 1 day gave a 3D coordination polymer {[Zn(IA)2]•4H2O}n (6). Interestingly, when transparent crystals 6 are allowed to stand in the reaction system for 6 days, they were transformed into a pale yellow compound {[Zn(IA)2]•H2O}n (7). Some non-coordinated salts like KF, KCl, KBr, NaCl can be added to control the time required for crystal transformation.
The structures of the seven coordination polymers were characterized by IR spectroscopy, elemental analysis and single-crystal or powder X-ray diffraction methods. The thermal stability of the products were examined by TGA.
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