The Construction Of Coordination Polymers Containing Carboxylic Acids And Dual-triazole Ligands, Structure And Nature Of The Study

Until now, imidazole and 1,2,4-triazole ligands, especially their derivatives, have been extensively employed in the construction of metal-organic coordination polymers with beautiful architectures and interesting properties because of their strong capacity of coordination, variously bridging fashions and biochemical property. In this thesis, a new flexible conformational 1,2,4-trizaole-based ligand 4,4'-bis((1,2,4-triazol-1-yl)methyl) biphenyl(btmb) (1) has been successfully synthesized from literature methods. With the aim of understanding of the coordination behavior of btmb, we select different polycarboxylates ligands act as auxiliary bridging ligands, nineteen new coordination polymers have been synthesized under hydrothermal conditions. All crystalline polymers have been structurally characterized by single-crystal X-ray diffraction, elemental analysis, IR, TGA and XRD. Moreover, the properties of these polymers have also been discussed in detail, such as thermal stability, luminescent and molecular magnetic behavior. The research content of this thesis consists of three sections:(1) Seven coordination polymers have been synthesized by the combination of three flexible V-shaped carboxylate ligands and btmb with different metal ions. All polymers display the similar 2D layer structure with different topologies. Further structural investigation shows that distinct conformational btmb and carboxylate ligands play important roles in the formation of resulting frameworks. Their thermal analyses reveal that the 1,2,4-triazole-based frameworks have high thermal stability. The luminescent properties of 2, 5 and 7 have also been investigated.(2) The simultaneous hydrothermal reaction of three related aromatic organic acids (H3btc, H3bta, H4btec) and long btmb ligand with metal ions affords six novel coordination polymers. All such polymers show intriguing structures and topological frameworks. The structural diversities indicate that distinct nature of organic acid ligands, metal ions and pH value play crucial roles in modulating the formation of resulting coordination complexes and the connectivity of the ultimate topological nets. Moreover, their thermal stabilities and luminescent property of 9 have been studied, magnetic susceptibility measurement of 13 indicates the presence of weak ferromagnetic interactions between the Co(II) ions bridged by carboxylate groups.(3) As an extension of our work, we have reported here a series of new coordination polymers 15-20 containing adamantane dicarboxylates (H2ADC and H2ADA) and flexible bis-triazole ligands with Zn(II)/Co(II)/Cd(II)-ions have also been synthesized. Structural diversities indicate that distinct adamantane dicarboxylates, conformational bis-trizaole ligand and nature of metal ions play crucial roles in modulating structures and topologies of the final polymers. Moreover, the thermal stability property of crystalline sample 15 has been investigated through TGA and VT-XRD measurements. The luminescent properties of 15,17, 18 and 20 have been studied.The systemic studies show 4,4'-bis((1,2,4-triazol-1-yl)methyl)biphenyl ligand is also a good candidate for construction coordinarion polymic framework due to its stronger coordination ablitily and flexible comformations. The thesis not noly gathers experience for the design and synthesis of founctional coordination polymers, but also provides important experimental basis and theoretical foundations for the the synthesis and property of triazole-based coordination polymers.