Synthesis And Catalysis Properties Of Coordination Polymers Based On Aromatic N-oxide And Benzimidazoles Ligands

The synthesis and properties of coordination polymers is the research hot-spot in the field of self-assembly chemistry.Self-assembly of supramoleculars is the aggregation of molecules through intermolecular interactions to form an ordered structure of the aggregate phenomenon,which often show the unique characteristics and functions that the single molecules or low molecular aggregates do not have.In this work,a series of ligands with N-oxide groups and benzimidazole groups were designed and synthesized.The coordination chemistry based on these ligands and transition metals was investigated.13 new coordination polymers with novel structure and excellent properties were obtained.Then,they were characterized by powder diffraction,X-ray single crystal diffraction,IR and TGA.What's more,the catalytic properties of the representative coordination polymers were studied.? Five complex coordination polymers were obtained by self-assembly between transition metals and the two pyridine N-oxide organic ligands with pyridine as the end coordination groups in our study group.Among them,four of these coordination polymers are different from others,because oxygen atoms in the pyridine N-oxide groups do not coordinate with metals.Thus,the Knoevenagel condensation reaction was catalyzed by the nature of the free N-oxides as Lewis-base sites.They were used as heterogeneous catalysts,which can be reused 5 times,showing the high catalytic efficiency and selectivity.? The carboxylic acid groups were introduced into thepyridine N-oxide organic ligands.Four coordination polymers with the complex and stable structure were obtained by self-assembly with transition metals in the solvent thermal conditions.The coordinated solvent molecules(DMF)were attempted to exchange with other small functionalized molecules,which are expected to be used for the identification of amino acids.? A series of organic ligands with benzimidazoles groups were designed and synthesized,and 4 complex coordination polymers were obtained after self-assembly with transition metal.What's more,in the process of self-assembly,the ligand undergoes a fracture of the carbon-carbon bond,the product after the carbon-carbon bond breaks were speculated and proved.