Study On The Constructions And Properties Of Coordination Polymers Based On V-Shaped 2,6-bis(4'-carboxyl-phenyl)pyridine Ligand

Discoveries of novel functional materials have played very important roles to the development of science and technologies and thus to benefit our daily life.Among all kinds of materials,metal-organic frameworks?MOFs?,as a unique porous coordination polymer,have attracted extensive attention due to their inherent advantages such as orderly structure,designable structure and wide application,etc.However,due to the many factors affecting the synthesis of MOFs,the reasonable design and construction of the required structure and performance of MOFs is still a formidable challenge.Therefore,an aromatic V-shaped 2,6-bis?4'-carboxyl-phenyl?pyridine ligand?H₂L?with C₂symmetry,transition metal ions Zn???,Co???,Cd???and alkali metal ions Ba???are chosen to construct six different complexes by solvent thermal method:[Zn₄?L?₃O]�8DMF�H₂O?1?,[Zn_4-xCo_x?L?₃O]�8DMF�H₂O?2?,[Zn?L??H₂O?]?3?,[Ba?L??DMF??H₂O?]�DMF?4?,[Cd?L??H₂O?]�0.5DMF�0.5H₂O?5?,[Cd?L??4,4'-bipy?]�DMF�4H₂O?6?,and the luminescence,adsorption and catalytic properties of the above complexes were investigated.The research content of this paper is divided into four chapters:Chapter 1:The brief introduction,design and synthesis strategies and application prospects of coordination polymers are described,and the significance and research progress of this thesis are discussed.Chapter 2:Complexes 1 and 3 were first synthesized successfully with Zn???ions and H₂L ligand.Then,the isomorphic complex 2 was prepared by partially replacing Zn???ions with Co???ions into the structure of 1 via the direct synthesis method.Complex 1 is a probe used for sensing Fe³⁺,Cu²⁺ions and nitrobenzene and can selectively adsorb methylene blue?MB?dyes.Notably,the CO₂adsorption demonstrated that complexes 1and 2 showed the special gate-opening effect at low temperatures.Chapter 3:Three-dimensional complex 4 was synthesized with ligand H₂L and alkaline earth metal Ba???ions.The study showed that complex 4 had adsorption properties for CO₂at different temperatures,the high catalytic activity for CO₂cycloaddition reaction under mild conditions,and excellent sensing properties for Fe³⁺and Cr₂O₇^2-.Chapter 4:Complex 5 was first synthesized by Cd???ions and H₂L ligand assembly.On this basis,complex 6 was formed by addition of the 4,4'-bipy ligand.Complex 6 exhibits porous structure and excellent catalytic efficiency and recyclability in CO₂cycloaddition reactions.In addition,the two complexes have unique luminescent properties.