| Triazole ligands containing pyridine group contain not only nitrogen heterocycles,but also aromatic rings.It has delocalized?electron conjugation system and various coordination modes.It can be used to construct novel coordination polymers with various metal ions,and it is an ideal coordination building unit.In this thesis,two kinds of triazole ligands containing pyridine group are the main ligands,and halogen and pseudo halogen ions are the auxiliary ligands.They have synthesized eight kinds of coordination polymers with different structures with transition metal ions.Their structures,optical properties,thermal stability and luminescence origin are also studied.Using 3,5-bis(4-pyridyl)-1,2,4-triazole ligands(4,4'-Hbpt)as main ligands and halogen ions as auxiliary ligands,three coordination polymerization were synthesized:[Cu Cl(4,4'-Hbpt)]n(1),[Cu2Br2(4,4'-Hbpt)2]n(2),[Cu3I3(4,4'-Hbpt)]n(3).In coordination polymer1,there is a one-dimensional zigzag chain structure,and one-dimensional chains form a two-dimensional layer structure by hydrogen bonding.In coordination polymer 2,the chain is connected into a two-dimensional junction by hydrogen bonding and?-?interaction.In coordination polymer 3,the auxiliary ligands iodine ions bridge copper metal ions to form two kinds of chains with different structures:"single ladder"chain and"double ladder"chain.There is weak interaction between copper ions.The two chains are connected by4,4'-Hbpt to form a wave like two-dimensional structure with alternating single and double chains.The peak shapes and positions of the excitation peaks and emission peaks of coordination polymers 1 and 3 are similar,which may be due to their similar charge transition modes.And their thermal stability is good.So this kind of materials has the potential to be blue light(450 nm-490 nm)materials.Based on the first principle of Density Functional theroy,the band structure and density of states of coordination polymer 1-3 are calculated.By analyzing the band structure and density of states of each coordination polymer,the possible origin of their luminescence is explored,which provides theoretical basis for the preparation of practical optical materials.The luminescent origin of coordination polymers 1 and 2 is mainly the transition from metal ions to ligands.The luminescence origin of 3 is mainly the transition from metal ions to ligands and from a small amount of ligands to ligands.Using 3,5-two(4-pyridyl)-1,2,4-triazole ligand(4,4'-Hbpt)as the main ligand and quasi halogen ion CN-as the auxiliary ligand,three coordination polymerization were synthesized:[Cu4(CN)4(4,4'-Hbpt)]n(4),[Cu5(CN)5(4,4'-Hbpt)]n(5),[Cu2(CN)2(4,4'-Hpbt)·C H3CN·2H2O]n(6).The organic ligand 4,4'-Hbpt connects the one-dimensional chain into a two-dimensional surface,and the two-dimensional surface is stacked into a three-dimensional structure by the disordered CN-and the interlayer?-?interaction in coordination polymer 4.In coordination polymer 5,the one-dimensional chain formed by the disordered CN-bridged Cu3 is embedded in the three-dimensional framework structure.In coordination polymer 6,one dimensional helical chain is connected by 4,4'-Hpbt to form a two-dimensional structure.The thermal stability of 4 and 5 is better,and the thermal stability of 6 crystal structure is relatively poor due to the existence of guest solvent molecules.These three polymers have good fluorescence properties and they have the potential as luminescent materials.The ligands 4-amino-3,5-bis(4-pyridyl)-1,2,4-triazole(Hbpt-NH2)were prepared by a simple organic synthesis method,and two new coordination polymers were synthesized with the ligand as the main ligand and the halogen ion as the auxiliary ligand:[Cu3I3(Hbpt-NH2)]n(7)and[Co Cl2(Hbpt-NH2)]n(8).In coordination polymer 7,the ligand Hbpt-NH2bridges the metal copper ions to form a two-dimensional network structure,and the two-dimensional surfaces accumulate into a three-dimensional structure by abundant hydrogen bonding.In coordination polymer 8,the ligand Hbpt-NH2bridges the metal cobalt ions to form a one-dimensional zigzag chain,and the chains form a two-dimensional structure by hydrogen bonding.Based on the first principle of Density Functional theroy,the band structure and density of states of coordination polymer 7 and 8 are calculated,and the possible luminescence origin is explored.The luminescence origin of 7 is mainly the transition from metal ions to ligands and from a small amount of ligands to ligands.The luminescent origin of coordination polymers 8 is mainly the transition from metal ions to ligands. |
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