Studies On 3d/4f-Coordination Polymers With Carboxylic Acid Ligand

Coordination polymer chemistry is one of the hotspots in coordination chemistry.Coordination polymers have many excellent properties.Porosity is the significant one among these properties.Porosity plays a pivotal role in gas adsorption,fluorescence sensing,ion doping,light color adjustment and other fields.The main contents of this article are as follows:First,the basic concept and development course of coordination polymers are briefly described.And we also introduce the design theory and synthesis principle of coordination polymers.The coordination polymers are the kind of porous materials with extremely diverse species.The corresponding classification of the coordination polymers is introduced according to different standards.We also recommend the application of coordination polymers in different fields and their research development in their own fileds.Second,two kinds of Zn²⁺coordination polymers C₂₅H₂₇N₃O₇Zn₃?1A?and C₂₂H₂₀N₂O₆Zn?1B?were obtained by adjusting crystal growth temperature.These complexs were constructed by bridging ligand 4,4'-???1R,2R?-cyclohexane-1,2-diyl?bis?azobisyl?bis?carbonyl??dibenzoic acid L₁ and Zn²⁺metal ions.The coordination polymer 1A was obtained by solvent volatilization at room temperature with one-dimensional chain structure;and the coordination polymer 1B was obtained by solvothermal method presenting two-dimensional layer structure.In order to explore the property of the transition metal complexes,Cd²⁺took the place of Zn²⁺.The two-dimensional layered coordination polymer C₂₂H₂₀N₂O₆Cd?1C?was obtained by solvothermal method.It was found that these coordination polymers were unfit for luminescence materials due to their poor fluorescence properties.In order to improve the luminescence properties of these coordination polymers,we try to use post-synthesis method to get luminescence materials hoping that luminescent lanthanide ions can doped into the porous structure of the two-dimensional structure1B and 1C.Luminescence spectrum showed that the doping materials emits the characteristic emission peaks of Eu³⁺and Tb³⁺.So we explored the luminescence properties of doping materials.White light emission was achieved by adjusting the excitation wavelength and ratio of Eu³⁺and Tb³⁺in the doped materials.And the Tb³⁺doped luminescent material was used for sensing organic solvent acetone molecules according to the luminescence quenching phenomenon of Tb³⁺.Luminescence properties of 1B were improved greatly by post-synthesis method.The X-ray powder diffraction study showed that the rare-earth doped material holds the structural integrity of the skeleton 1B.In addition,the adsorption capacity of 1B for dyes was also studied.Third,carboxylic acid organic molecules are often used to construct metal-organic-frameworks?MOFs?as bridging ligands.A series of carboxylic acid ligands were designed and synthesized.Their structures are characterized and confirmed by ¹HNMR,¹³CNMR and FT-IR spectrum.We also explored and optimized the synthetic routes of these ligands.Three lanthanides coordination polymers C₁₅H₁₈NO₁₀Ln[Ln=Er³⁺?2A?,Tm³⁺?2B?and Yb³⁺?2C?]were synthesized by solvothermal method using L₂ 2,2'-??5-carboxy-1,3-phenylene?bis?oxy??diacetic acid as bridging ligand and luminescent lanthanide ions as metal centers.The structures of these coordination polymers were revealed by Single crystal X-ray diffraction.The structure of bulk samples were characterized by X-ray powder diffraction?XRD?.We also tested the near-infrared luminescence properties of these coordination polymers.