| The rational design and synthesis of metal-organic coordination complexes with specific network structures (including multi-nuclear discrete coordination architectures and polymeric coordination networks) and physicochemical properties by using the experience and method of crystal engineering has currently been a hot research topic in coordination chemistry, supramolecular chemistry, material chemistry, and other relevant areas. As a new type of molecular-based crystalline materials, metal-organic coordination complexes (especially microporous coordinaton polymers) have exhibited potentially various applications in many fields such photoluminescence, electric conductivity, magnetism, adsorption/separation, and selective catalysis. The appropriate choice of well-designed organic tectons (building blocks) and metal ions or clusters (metal nodes) is one of the most effective ways. That is, utilizing suitable organic tectons with various functional groups that are capable of bridging metal centers to construct such crystalline materials has demonstrated to be an active area of multidisciplinary research, being in connection with crystal engineering, coordination/supramolecular chemistry, and material science. Thus far, the theoretical forecasting of the corresponding structures and functions of such complexes is still remained to be very difficult because they might be affected by many factors. Therefore, it is still necessary to systematically study the synthesis and structures of such complexes by carefully design and selection of suitable ligands, as well as the relationships between the ligand natures and complex structures.In comparison with the usually aromatic benzene-based carboxylic acids, however, far less common has been the studies on bulky aromatic ring-based and saturated alicyclic or heteroalicyclic-based carboxylic acid ligands whose coordination chemistry of transition metals has been rarely investigated to date. One the one hand, such ligands bearing the bulky aromatic skeletons have several typically characteristics: (1) the electronic nature of its extendedπ-conjugated system and the steric hindrance of the bulky naphthalene ring that may affect the coordination modes of carboxylate, and thus, determine the final coordination arrays; (2) the extendedπ-conjugated system that normally results in C–H???πand/orπ???πstacking interactions from the viewpoint of the electronic nature, along with the increased overlap of the aromatic surface areas, play an important role on forming the final supramolecular lattices, namely, extending the low-dimensional coordination entities into higher-dimensional supramolecular networks. On the other hand, flexible alicyclic or heteroalicyclic multicarboxylate ligands generally have richer coordination modes and more flexible ring skeletons, which may not only affect the coordination abilities and modes of relevant carboxylic groups but also remain largely unexpected in the process of constructing metal-organic frameworks (MOFs), and also make them more difficult to predict and control the final coordination polymers.Considering all the aspects mentioned above, in this dissertation, several carboxylic ligands with differently novel ring skeletons (naphthalene, tetrahydrofuran, oxirane, and etc) were selected to react with some transition metal ions, and related metal complexes with 0D, 1D, 2D or 3D structures have been obtained and characterized by elemental analyses, IR, and X-ray crystallography. Moreover, the corresponding luminescent/magnetic/thermal properties of the complexes have also been investigated in detail. Also, the factors governing the framework formations of these complexes were discussed. The main contents consisting of four chapters have been summarized as following:In chapter 1, a brief introduction of the backgrounds and relative concepts of this work were presented. The progress of the coordination chemistry of the related carboxylic ligands was concisely reviewed, and the research significance and main conclusions of this dissertation were summarized.In chapter 2, three series of six CdⅡ, three ZnⅡ, and three AgⅠcoordination complexes were synthesized by using naphthalene-2,3-dicarboxylic acid (H2L1) and different N-donor auxiliary co-ligands (chelating or bridging) such as 2,2′-bipyridine, 1,10-phenanthroline, 4,4′-bipyridine, rans-4,4′-azobis(pyridine), and 1,3-bis(4-pyridyl) propane, and structurally characterized by elemental analyses, IR, and X-ray diffraction analysis. Also, the luminescent properties of the corresponding d10 complexes mentioned above have been further investigated.In chapter 3, in order to systematically investigate the influence of the ring skeleton with flexible heteroatomic multicarboxylic acid ligands on the related structures and properties of their complexes, we synthesized and characterized nine CuⅡ, three MnⅡ, five CdⅡ, and two AgⅠcomplexes with tetrahydrofuran-2,3,4,5-tetracarboxylic acid (H4L7), cis-epoxysuccinic acid (H2L8), and (+/-)-trans-epoxysuccinic acid (H2L9), respectively, and sometimes incorporating different auxiliary ligands. The results reveal that, in comparison with structurally related aromatic ring-based multicarboxylic acid ligands, the small bulk flexible alicyclic-based multicarboxylic acid ligands of H4L7 H2L8, and H2L9, have the more flexible ring skeletons, from the viewpoint of geometry requirements, for the formation of the intra- and/or inter-network hydrogen-bonding (O–HO or C–HO) interactions, especially in the process of linking the low-dimensional entities into higher-dimensional supramolecular frameworks.In chapter 4, along that line of research in chapters 2 and 3, we, by employing the 5,6-dihydro-1,4-dithiin-2,3-dicarboxylic anhydride as a primary ligand, also synthesized and characterized four CuⅡ, two MnⅡ, one AgⅠ, and four CdⅡcomplexes, and sometimes together with different auxiliary ligands. The related luminescent/thermal properties of such complexes have been further investigated and discussed in detail.In chapter 5, Conclusion remarks on my dissertation. |
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