| Crystal engineering is widely involved in the field of metal-organic coordination polymers, and is becoming a powerful strategy for rational structure construction and function improvement. As a result, the knowledge of synthetic chemistry is significant enriched, and a large variety of complex compounds are intruduced, with not only structural diversities but also promising potential applications, such as sorption and hydrogen storage, catalysis, enantiomeric discrimination, optics, magnets and sensors.In recent years, the transition and lanthanide metals are extensively studied in the field of coordination polymers. On the other hand, the actinide elements are less recognized. Among them, the uranium compounds are attracting increasing research efforts, because of their rich structure topologies and numerous properties.Series of uranyl-containing coordination polymers are obtained under hydrothermal conditions and studied from structural and functional perspectives. Meanwhile, a U(IV) phosphate compound is also synthesized and discussed. This thesis is completed by 4 chapters.In the introduction part (Chapter 1), the development of coordination polymers are briefly reviewed, with major emphases on the uranyl compounds, including the synthesis and structures and photoluminescent and photocatalytic properties. Also the goals and achievements of this thesis are summarized.In Chapter 2, a series of 5 uranyl assembly compounds are introduced: (UO2)3(v-BTC)2·4H2O (1), (UO2)6(OH)2(m-BTC)2(m-HBTC)2(H2O)2·7H2O (2), (UO2)4O2(m-BTC)2(NC2H8)2·H2O (3), (UO2)2O(H2BTEC)(NHC2H6)2·H2O (4) and (UO2)3(H2BTEC)3·18H2O (5). The strategy is to employ the sterics between the carboxylate groups to give rise to three-dimensional connectivity of the ligands, in order to cross link the planar uranyl species into 3D frameworks. In fact, Compounds 1, 2 and 3 follow the prediction, and 3D structures are form for these three compounds. In 1, the structure is composed from isolated seven-coordinated and eight-coordinated uranyl sites connected by BTC linkers. In 2 the mononuclear uranyl centers and tetranuclear clusters coexist, and leads to 1D channels within the structure. Upon removal of guest molecules in the channels, 2 exhibits microporous sorption properties. All uranyl sites in 3 polymerize into the same tetranuclear clusters, and result in even larger channels than 2. But the removal of the guest species in 3 is not successful yet. The comparison of pore size between 2 and 3 reveals the relations between guest molecules and pore structures. Compounds 4 and 5 crystallize into layered structures. The uranyl units polymerize into tetranuclear clusters in 4 while stay as isolated monomers in 5. It is noticed that the ligand structure in not the only key to determine the product dimension. In fact, several factors cooperate to control the overall structure. Besides, all these 5 compounds exhibit typical uranyl fluorescent emission.In Chapter 3, a series of 3 compounds are synthesized in association with NDC and bipyridine ligands: (UO2)8(NDC)12(4,4'-bipyH2)3(4,4'-bipyH)3 (6), (UO2)3O[Ag(2,2'-bipy)2]2(NDC)3 (7) and (UO2)2(NDC)2(2,2'-bipy)2 (8). 6 and 7 are layered compounds. The layers of 6 are constructed from seven-coordinated uranyl monomers and NDC linkers. In 7 it consists of both tetranuclear clusters and monomers. The apertures within the layers packed into channels, which are filled with 4,4'-bipy species and Ag(2,2'-bipy)2+ complex ions for 6 and 7, respectively. In 8 both NDC and 2,2'-bipy ligands coordinate to uranyl centers, and results in a 1D chain structure. The photocatalytic activities of 6 and 7 are compared, and the results proves the photocatalytic property is contributed by uranyl ions along, while the Ag(2,2'-bipy)2+species have little contribution to this property. The correlations between photocatalytic degradation rate and oxygen concentration are also elucidated. The photocatalytic degradation reaction is very sensitive to oxygen at low oxygen level. With rising O2 concentration, the photocatalytic degradation accelerates but at descending rate. This phenomenon is in good agreement with the proposed photo- catalytic degradation mechanism.Nowadays the research of uranium compounds expands to uranium-inorganic framework and low valence uranium compounds. Compared to the U(VI) families, the low valence uranium compounds may exhibit interesting properties because of their electron configurations of uranium ions. In a ethylenediamine-phosphoric acid system, a uranium(IV) phosphate layered compound U3(PO4)6(H2en)3 (9) is obtained both form direct one-pot reaction or pre-reduction process. The uranium ions are in slightly distorted octahedron environment, and are stable to air or moisture. Further study reveals the up-conversion fluorescent emission of 9.
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