Design,Syntheses,Structures and Properties of Porous Coordination Polymers Based on Pyridyl-carboxylate Ligands

Author:Zhou Hui Fang

Supervisor:wang yao yu


Degree Year:2018





Porous coordination polymers are a new type of porous crystal materials constructed by selfassembling metal ions/clusters with multifunctional organic ligands in appropriate conditions.Compared with conventional porous materials,porous coordination polymers possess extraordinarily high surface areas,designable frameworks and modified internal surface properties.In the past two decades,porous coordination polymers have shown great potential applications in gas separation and storage,sensing,dye degradation and drug delivery.Porous coordination polymers,owing to the high-density unsaturated metal active sites and the high porosity,exhibit excellent performance in heterogeneous catalysis.Because the structure of the porous materials is much more complex and diverse than the traditional porous materials,it is particularly important to study the structure-property relationship,and the design and synthesis of function-oriented porous coordination polymers is still a challenge.This dissertation concentrated on the construction of porous coordination polymers based on reduced symmetry pyridylcarboxylic ligands and explored suitable synthesis strategy for giving full play to the function of pyridine and carboxylic groups in the framework to prepare porous materials with stable structure and excellent performance;and it was also explored about the effect of the pyridyl groups and carboxyl groups on the structure and properties to provide new ideas and methods for the construction of novel pyridyl-carboxylate porous frameworks.Based on the above ideas,a series of pyridyl-carboxylate porous coordination polymers have been synthesized and characterized.The main details are as follows:Chapter 1 gives a summary of the development,synthesis and application of porous coordination polymers,as well as a brief review of research progress on pyridyl-carboxylate porous coordination polymers and the research ideas and progress of this dissertation.In Chapter 2,by shifting the coordination sites of ligands,the solvothermal reactions of four positional isomeric asymmetrical pyridyldicarboxylatic acids with Cd(NO3)2 generated four coordination polymers,of which Structures,luminescence,and gas adsorption properties were comparative studied through systematically tuned the carboxyl and pyridyl groups of the positional isomeric.This work not only explores the essential factors of positional isomeric ligands for regulating structural assembly and properties,but also provides further insight into the rational design of new functional crystalline materials from the positional isomeric ligands.Chapter 3 introduces a new strategy to build porous pillared-layer frameworks based on predesigned ligands.Three pillared-layer coordination polymers with high porosity were successfully synthesized by employing bipyridyl and tricarboxylic acid mixed ligands and pyridyldicarboxylate ligands.All materials exhibit high uptake capacities for C2H4 and CO2 and high selectivity for C2H4 and CO2 over CH4 gases.The results open a new blueprint on the synthetic design of pillared-layer MOFs for future applications.Chapter 4 presents a chemically stable Zn4O-based self-penetrating metal–organic framework based on a carboxylate ligand derived from benzene-1,4-dicarboxylate,which exhibits outstanding chemical stability and can be well retained in not only diverse boiling solvents and water but also the aqueous solutions with p H ranging from 3 to 12,showing a rare case of super-stable Zn4O-MOF.Based on the structure with permanent porosity,high-density metal catalytic sites and excellent stability.It showed high CO2 capture and efficient catalytic conversion for CO2 cycloaddition with epoxides under mild conditions and outstanding recyclability.Chapter 5 reports two microporous coordination polymers based on quaternary SBUs with new(3,3,4,6)-connected topology,which were constructed by using the mixed ligand of pyridyldicarboxylate and tetrazole.Both frameworks possess high porosity with suitable pore sizes and highly polar pore systems,leading to remarkable uptake for CO2 and significant selectivity for CO2 over CH4,especially for the NH2-decorated framework.This work confirms the effective strategy to improve the adsorption uptake and selectivity for CO2 by imbedding-NH2 groups in porous materials.A brief summary of this work.