Copper(Ⅰ) Halide Cluster-based Metal Organic Frameworks: Synthesis And Properties

Metal-organic frameworks(MOFs), self-assembled from inorganic components and organic linkers, are new type of organic inorganic hybrid materials. Because both the inorganic and the organic moieties can provide the platforms to generate luminescence, they are certainly very promising as a multifunctional luminescent material. Furthermore, the π-π interactions or some guest molecules within MOFs can also emit and/or induce luminescence. In the inorganic or organic components which are used for constructing luminescent MOFs, the polynuclear copper(I) halide clusters with abundant structural motifs and rich photochemical and photophysical property have been hotspot in inorganic chemistry. The MOFs which constructed by copper(I) halide clusters are a class of promising luminescent materials with potential applications in organic light-emitting diodes, bioimaging and fluorescent chemosensors. However, the copper(I) halide cluster-based MOFs which have successfully been synthesized and displayed excellent luminescence properties are limited. Consequently, it is challenging and significant to construct novel copper(I) halide cluster-based MOFs with various luminescence properties. There are five chapters in this thesis. In the first chapter, the related concepts, research methods, background and developments of copper(I) halide cluster-based compounds are introduced.In the second chapter, five compounds [Cu6I8(C16H32N4)](1), [Cu4I6(C16H32N4)](2), [Cu4I6(I2)2(C16H32N4)](3), [Cu3I4(C16H32N4)]?Cl O4￣(4) and [Cu6I6Br2(C16H32N4)(CH3CN)2](5) have been synthesised by solvothermal reactions. In compound 1, the structure of the copper(I) halide cluster is a two-dimensional(2D) layer. The structure of the copper(I) halide cluster in the other four compounds are one-dimensional(1D) chains. Apart from compound 3, they display excellent solid-sate photoluminescence properties. The emission maximum of compound 4 appears large red-shift at low temperature. The luminescence of compound 5 is reversible when the coordinated CH3 CN molecules in structure are removed by heat and recovered from acetonitrile solvent.In the third chapter, four novel compounds, namely [Gd2(Cu2I2)(C6H4NO2)6(C3H7NO)(H2O)]?(C3H7NO)(6), [Gd2(Cu4I4)(C6H4NO2)6(C3H7NO)2](7), [Gd2(Cu6I6)(C12H8NO2)6(C2H6O)2(H2O)2](8) and [Gd2(Cu8I8)(C12H8NO2)6(H2O)4]?5(C4H8O2)(9) have been solvothermally synthesized. Four copper(I) halide clusters with different size and shape are respectively incorporated in the three-dimensional(3D) frameworks of the four compounds. The four compounds exhibit excellent solid-sate photoluminescence properties at room temperature. Interestingly, compound 8 responds to external mechanical force. After grinding, the fluorescence has obviously quenched. Compound 9 displays reversible luminescence behavior accompany the removal and recovery of the guests molecules in the channel.In the fourth chapter, Four 3d-4f luminescent MOFs, [La2(Cu8I8)(pba)6(C4H8O2)2(H2O)2]?3(C4H8O2)?2(H2O)(10), [Ce2(Cu8I8)(pba)6(H2O)4]?5(C4H8O2)(11), [Eu2(Cu8I8)(pba)6(H2O)4]?5(C4H8O2)(12) and [Tb2(Cu8I8)(pba)6(H2O)4]?5(C4H8O2)(13) are synthesized under the same solvothermal condition. Their structures are the same as compound 9. These analogues display unique photoluminescence property at room temperature. Since compound 13 has displayed two distinct emission bands from different luminescent centers, we mainly focus its luminescent property. Owe to the unique porous structure and dual luminescent centers of compound 13, it can efficiently differentiate different kinds of small organic molecules. The luminescent colour of MOF sensor in different guest solvents has obvious changes. This multicolour luminescence originates from emissions of the dual luminescent centers and the emissions have shifted, enhanced, weakened or quenched in different degree.In the last chapter, we make a summary of this thesis. It involves the design, synthesis and luminescent properties of copper(I) halide cluster-based MOFs. The structures and luminescence of these compounds have been carefully analyzed and studied. Based on these excellent properties, these materials inspire us that copper(?) halide cluster-based MOFs are promising for research in sensor application.