Tuning Structures And Properties Of Metal Complexes With Pyrazine-Based Tetrazolate/Carboxylate Ligands

In this dissertation, a series of structurally related pyrazine-based ligands containing tetrazole, bis-tetrazole or carboxylate coordination groups have been designed and synthesized, and forty-five complexes of these ligands with various structures have been prepared and characterized. Luminescent, gas adsorption, magnetic and the solid-state circular dichroism (CD) properties of selected complexes have been studied. The results show that coordination modes, substituting groups and coordination affinity of ligands, the binding nature of metal ions, and reaction conditions have significant influences on the formation and related properties of complexes. The main results have been summarized as follows:1.2-(1H-tetrazol-5-yl)pyrazine ligand (HL) and its six ZnⅡ, CdⅡ, HgⅡcomplexes have been synthesized and characterized. The luminescent properties of some complexes have been investigated. The influences of the nature of metal ions and reaction conditions, as well as the intramolecular/intermolecular weak interactions in the formation of such complexes have been investigated.2. A series of structurally related 2,3-substituded-5,6-di(1H-tetrazol-5-yl)-pyrazine ligands bearing different terminal groups, such as alkyl, aryl, pyridine have been designed and prepared, and twenty-three coordination complexes with these ligands have been synthesized and characterized. The luminescent properties of these ligands and some of their complexes in solid state at room temperature, magnetic properties and the solid-state circular dichroism(CD) properties of some complexes have been also studied and discussed. The effects of substituting groups of these ligands and synthesis conditions, as well as other factors on the formation of their coordination complexes have also been discussed. The results show that the variety of substituting groups of the bis(tetrazole)ligands can cause dramatic changes in the formation of their complexes.3. Four pyrazine-2,3-dicarboxylate ligands with different substituting groups which have similar skeleton to those of pyrazine-based ligands mentioned above and their sixteen metal complexes were synthesized and characterized. The luminescent properties of ZnⅡ, CdⅡcomplexes and the corresponding ligands, magnetic properties of some complexes have also been investigated. The effects of substituting groups of ligands and reaction condinations on the structures and properties of the complexes have been discussed.