Controlled Synthesis, Structure Regulation And Fluorescence Of CuI-Based Inorganic-Organic Hybrid Materials

Metal-Organic Frameworks(MOFs) have attracted extensive interests in the field of chemical materials due to their potential applications in gas adsorption, gas storage, gas separation, heterogeneous catalysis, molecular detection, drug delivery, and so on. Especially, those complexes based on cuprous iodide are currently at the forefront of coordination chemistry and crystal engineering research because of the potential applications in luminescence and lighting filed.In this dissertation, we successfully prepared series of novel Cu I-based MOFs by using different bridging ligands and modulating reactions conditions. Their structure and optical properties were also studied. Specific contents are as follows:(1) Two cuprous iodide pseudo-polymorph,(Cu4I4)(MBI)2(1) and(Cu4I4)(MBI)2(C2H3N)(H2O)8(2), with cuprous iodide clusters(Cu4I4) as building block and organic imidazole as bridging ligands were successfully synthesized by modulating the reactions conditions. Although compound 1 and 2 have the same secondary building units and bridging ligands, they have quite different structures. The structures of compound 1 and 2 are two-dimensional layered structure and three-dimensional open framework structure, respectively.Compound 1 and 2 have similar fluorescence properties due to their same secondary building units and bridging ligands. The average Cu···Cu distances in those compounds are shorter than the sum of the Vander Waals radii of copper, so compound 1 and 2 only exhibit a single broad low-energy cluster-centered(3CC) triplet emission band at both room temperature and 77 K. Compounds 1 and 2 both have thermochromic properties. Upon lowering the temperature, the maximum emission peaks of two compounds have a red shift. In order to gain further insight into the influence of ligands on luminescence properties, we also synthesized molecular complex(Cu4I4)(MIM)4(3). The fluorescence properties of the compound are mainly affected by Cu···Cu distance.(2) Two novel compounds,(Zr6O8)(OH)8(Cu4I4)2L8(4) and(Zr6O8)(OH)8(Cu Cl2)6L12(5), with zirconium oxide clusters and cuprous iodide clusters as building units were synthesized through solvothermal reactions. Interestingly, the structural difference between these two compounds is only caused by different addition sequence of raw materials. Compound 4 is based on 8-connected Zr6O8 clusters and 4-connected Cu4I4 clusters. This is the first example of a porous MOF with flu topology constructed from Cu4I4 clusters. Compound 5 is composed of the 12-connected Zr6O8 cluster and 2-connected Cu Cl2 nodes. The topology of compound 5 is similar to Ui O-66.(3) Up to now, many fascinating Cu I-based MOFs with DABCO ligands have been synthesized. However, Cu I-based MOFs with both Cu8I6 and Cu4I4 clusters as building units and DABCO as bridging ligands have not been reported. Herein, we synthesized a novel compound((Cu8I6)(Cu4I4)2(DABCO)8(6)) through solvothermal reaction. The 8-connected Cu8I6 cluster and 4-connected Cu4I4 cluster are linked by DABCO ligands to form three dimensional structures with flu topology. Similar to other Cu I-based MOFs with DABCO ligands, the fluorescence properties of compound 6 are dominated by triplet LE emission. When lowering the temperature, the maximum emission has a red shift.