Synthesis, Structures And Properties Of Cu⁺/cu²⁺/zn²⁺ Complexes Based On Diazole Ligands

In this work, three diazole ligands, 3,3',5,5'-tetramethyl- 4,4'-bipyrazole (hereafter shorten for H2Bpz), 2,2'-biimidazole (H2biim), 3,5-pyrazoledicarboxylic acid (H3Pzdc) were designed and synthesized. Using these ligands to react with copper or zinc salts in the absence or presence of secondary ligands, we obtained eleven coordination complexes, ranging from zero-dimension (0D) to 3D. The single crystal structures and the powder X-ray diffraction, luminescence and thermoproperties of these products were investigated preliminarily, through which some conclusions and suggestion to design functional of analogous complexes, were drawn. This paper consists of five chapters, presented as following.Chapter 1 introduces briefly the research progress of coordination chemistry and the general preparation and typical synthesis of coordination compounds and the factors affecting the structures of complexes. Subsequently a survey on the on-going advance of H2Bpz and H2biim coordination chemistry is made and finally the aim of the present work is elucidated.In Chapter 2, the synthetic details and structures of complexes 1-3 are described. The main aim of this lab work is to probe the discrimination of the hydrothermal reactions of diimidazole in the presence of secondary ligands as well as in different solvents, and it led to three diversely dimensioned Zn(II) complexes. X-Ray single crystal diffraction reveals that 1 (Zn2(H2biim)2(HBtc)2) is a 0D dinuclear annunation, in which the tetraazo diimidazole ligands are serving as chelating bidentate ligands, while 2 ([Zn2(Hbiim)(H2biim)(1,2-Bdc)0.5(H2O)2]n) exists as a 3D coordination polymer, in which diimidazoles coordinated as bridged ligands, and 3 ([Zn3(Btc)2(H2O)6]2H2O)n is a 1D polymer with the absence of diimidazole. Based on the facts, we analyzed the effects of coligand and solution acidity on the construction of products.Chapter 3 gives the detail of the synthesis, crystal structures and fluorescence of complexes 4 and 5. The arrangement is mainly aiming to explore the hydrothermal reaction behavior of diimidazole with CuI in different stoichiometries. The endeavor resulted in two coordination polymers, of which 4 ([Cu8(μ2-I)(μ3-I)6(μ6-I)(1,1'-DMBIM)3]n) forms as a 1D polymer, while 5 as a 3D one. Interestingly, the products show respectively a symmetric and an asymmetric dimethylation of diimidazole. More than that, 4 gives a novel vertex-sharing bicubane Cu8I7 cluster and 5 shows a two-fold interpenetration of the Cu4I4 cubane-based networks. Functionally the solids are both ambient photoluminous, giving off the emissions based on Cu-Cu interaction.In Chapter 4, the synthesis, structures and thermogravimetric property of complexes 6 and 7 are reported. The work aims to explore the influence of temperature on the assembly of coordination polymer. Under different temperatures, the reactions of bipyrazole and benzene-1,3-dicarboxylic acid with copper sulfate gave the 1D triple helical complex [Cu(μ2-H2Bpz)(μ2-1,3-Bdc)]n (6) and a 2D saddle catenation [Cu(μ2-H2Bpz)0.5(μ2-1,3-Bdc)]n (7). With the structural evidences it is proved that the high temperature is beneficial to the formation of thermodynamically favored product and that one can prepare the products with different structures and functionalities from the same starting material by controlling temperature.Chapter 5 presents the synthesis and structures of complexes 8-11 and the fluorescence of 9 and 11. Of the products, 8 [Zn2(Pzdc)2(H2O)4][(H3biim)2] forms as a 0D dimetallic complex,in which the biimidazoles are free coordination and exist as cocrystallizing molecules. However, the complex [Zn2(Pzdc)(μ2-H2O)(μ2-biim)0.5]n (9) is in 3D and contains biimidazoles as bridging ligands. The practice is to probe the coordination behaviors of diimidazole and bipyriazole. The product [Zn2(μ2-H2Bpz)2Cl4·2H2O]n(10) is a 1D helical structure with the bipyrazole as bridging. Likewise, the 2D complex 11 [Zn(μ2-H2Bpz)(HPzdc)]n contains also the dipyrazole as bridging.