Study On Synthesis And Properties Of Coordination Polymers Based On Novel Polydentate Nitrogen-Containing Ligands

With the rapid development of science and technology,coordination polymers have become the focus of research in coordination chemistry,material science,crystal engineering and other fields due to their diverse structures and excellent properties.They have shown broad application in the fields of fluorescence,adsorption separation,sensor,magnetism,energy,and so on.Because the self-assembly process can not be distinctively controlled,it is difficult to realize the directional synthesis of coordination polymers with specific structures and properties.However,the organic ligands play a key role in the structure and performance of coordination polymers.In this paper,we designed and synthesized N-donor ligands with varied conformation to construct 10coordination polymers with novel structures and excellent functions.The results are as follows:1.Synthesis and properties of coordination polymers based on new flexible N-donor ligandIn this chapter,based on a flexible N-donor ligand.1,1’,1’’-tris[（pyrine-4-yloxy）methyl]ethane（L1）,and dicarboxylic acids with different structures as the building unit,five coordination polymers,were synthesized under solvothermal conditions:[Zn₃（bdc）₃（L1）₂]·DMF（1）,[Mn₃（sdc）₃（L1）·H₂O]（2）,[Cd₄（bdc）₃（COO）₂（L1）₂]·7H₂O（3）,[Cd₂（ndc）₂L1]·6H₂O（4）,[Cd（tdc）L1]·2H₂O（5）.Compound 1 shows a two-fold interpenetration of 3,3,4,4,4-connected net;compound 2 forms a 3,6,8-connected three-dimensional network;compound 3 features a self-interpenetrating entangled network;compound 4 presents a 3,7-connected three-dimensional network and compound 5 exhibits a two-fold interpenetrating of 3,5-connected network.In addition,we further explored their photochemical properties in detail.The results show that compound 3 can be used as effective fluorescent probes for the detection of Fe³⁺and Cr₂O₇^2-.2.Synthesis and properties of coordination polymers based on sulfone-based rigid N-donor ligandsIn this chapter,based on two sulfone-based rigid N-donor ligands:4,4’-bipyridyl-2,2’-sulfone（L2）and 4,4’-bisimidazyl-2,2-sulfone（L3）.Five coordination polymers with novel structure and excellent fluorescence are synthesized:[Cd（1,4-bnc）L2]·xsolvent（6）,[Zn₂（bdc）₂（L2）₂]·xsolvent（7）,[Cd₂（sdc）₂（L2）·DMF]（8）,[Zn（bpde）L2]·xsolvent（9）,[Zn（bpde）L3]（10）.Compound 6 shows a three-dimensional sqc topological network.Compund 7 features a two-fold interpenetrating of pcu network.Compund 8 presents a 2D rotaxane-like structure.Compund 9 exhibits a four-fold interpenetrating of pcu network,and compound 10 shows an eight-fold interpenetrating of dia network.The thermal stability of these five compounds was characterized by thermogravimetric analysis（TGA）in details.Their fluorescence detection of metal cations and anions were also further investigated.The results show that compounds 7and 8 can be used as fluorescent probes for the detection of Fe³⁺and Cr₂O₇^2-.Compound9 can be used as a fluorescent probe to detect Cr₂O₇^2-.Compound 10 can be used as a fluorescent probe for detecting Hg²⁺.