Syntheses,Structures,Catalytic And Luminescent Properties Of Coordination Polymers Constructed From Polycarboxylic Acid Ligands

Coordination polymers?CPs?are an emerging class of crystal material constructed from coordination bonding connections between metal ions/clusters and organic linkers,featuring high porosity,high surface area and tunable pores'size and nature.By tuning the pore structures and modify the functional groups,CPs have been realized in applications in various fields,such as gas storage and separation,magnetics,biomedicine,sensing,non-linear optics and heterogeneous catalysis.CPs display excellent activity and selectively in a great number of reactions including oxidation,reduction,photocatalysis,electrocatalysis,etc.According to the structural features of CPs,the catalytic active centers are usually located at metal nodes,organic linkers or in the pores.The available pristine CPs catalysts and the suitable reaction types are very limited.Pore surface engineering is demonstrated to be an efficient way to design and prepare catalytic active CPs by creating more active sites and modulating the catalytic behaviors such as creating coordinatively unsaturated metal sites?CUSs?,ligand exchange,post-metalation,etc.In the field of optics,the white-light-emitting?WLE?and photoluminescent color-tuning?PLCT?properties can be easily achieved by fully applying coordination polymers?CPs?or MOFs.Lanthanide coordination polymers have special optical characteristics,including longer fluorescence lifetime,higher photoluminescence efficiency,and narrow emission bands.We can use Eu³⁺ions and Tb³⁺ions to emit red and green light-emitting properties in the visible region,and select suitable organic ligands to sensitize rare earth ions through"antenna effect"to obtain luminescent coordination polymer materials.According to the principle of three primary colors,we can control the concentration of different rare earth ions in the same skeleton,and realize the color modulation and white light emission of the material.The various components contribute to the final structural design of the framework,including organic linkers'design,linkage chelation,binding affinity,number of open metal sites,strength of metal-organic bonds,and partial symmetry.In this paper,on the one hand,by selecting carboxylic acid ligands and metal ions,we designed and constructed In,Sc-CPs with different structures under hydrothermal conditions,and studied their syntheses,structures and catalytic performance in Strecker reaction.The performance of coordinatively unsaturated metal sites as catalytic centers and different substrates in catalytic reactions were investigated in detail.On the other hand,we selected lanthanide luminescent ions and organic ligands to synthesize a series of luminescent coordination polymers.Based on the luminescent advantages of lanthanide ions,by adjusting the proportion of luminescent ions reasonably,we successfully synthesized lanthanide coordination polymer materials with tunable luminescence emissions including white-light emitting.The main research works are as follows:1.Two compounds were synthesized from rigid benzimidazole dicarboxylic acid?H₃bidc?ligands and metals indium?In?and scandium?Sc?,[InCl?H₂bidc?₂?H₂O?]_n?1?and[Sc?Hbidc??OH??H₂O?]_n?2?.Compound 1 exhibited 1D chain structure,and finally formed 3D supramolecular structure through intramolecular hydrogen bonding.2 shows a 3D supramolecular structure,built from left-and right-handed chiral layers along the c axis with the left-and right-handed chiral spiral chains.Interactions of?-?stacking between benzene ring and imidazole rings make the 3D supramolecular more stable.Both compounds 1 and 2 exhibited heterogeneous catalytic activity in the Strecker reaction of aldimine.The catalytic ability of compound 1 in different size reaction substrates was investigated in detail.2.Four compounds were synthesized by using the derivatives of isophthalic acid,5-amino-isophthalic acid?H₂aip?and 5-nitroisophthalic acid?H₂nip?.Their syntheses,structures and catalytic properties in the Strecker reaction were investigated in detail.The compound 3-5 contains helical structure and is obtained by solvent induction methods.The 3D structure of compound 3 contains not only left-and right-handed helical chains,but also 1D channels.Under the action of solvent induction,the helical structure can be modulated from compound 3 of left and right-handed helical chains to compound 4 of single helix chain.In addition,by changing the groups of ligands and changing the polarity of solvents,compound 5 with a single helix chain structure was obtained.In addition,CD spectrum showed that a large number of compounds 5were optically active.Compound 6 is a 3D open framework constructed by metal indium ions and contains abundant lewis acid catalysis sites.By studying the catalytic properties of the compound 3-6 in the Strecker reactions,it was found that the compound 3 exhibited more excellent catalytic activity than the 4-6 containing the catalytic site of the unsaturated coordination metal,mainly because the compound 3 was not only contains Lewis acid?unsaturated coordination metal center?and Lewis base?NH₂ group?dual catalytic active centers,and also contains 1D pores.In addition,compounds 3 and 6 can maintain high active after several catalytic cycles.3.A series of lanthanide compounds[Ln?PPDA??C₂O₄?_0.5?H₂O?₂]_n?nH₂O?Ln=Tb?7?,Eu?8?and Gd?9?Yb?10??with the same structure were constructed with semi-rigid ligand 4-?pyridin-3-yloxy?-phthalic acid?H₂PPDA?and lanthanide ions.These compounds exhibit isomorphic 2D layered network with rhombic windows.7and 8 show characteristic green and red emissions of the corresponding Ln³⁺ions,respectively,while 9 exhibits blue emission arising from PPDA^2-ligand.Since compounds 7-9 emit three primary colors,by adjusting the co-doping ratio of different Ln³⁺ions into the well-defined host framework,a series of codoped Ln-CPs Eu³⁺-doped 7 and Eu³⁺,Tb³⁺-doped 9 are synthesized,showing tunable luminescence emissions including white-light emitting.Compound 10 exhibits near-infrared luminescence property.4.Four compounds,[M?L?_0.5?4,4'-bipy?]_n?M=Co?11?,Cu?12?,Zn?13?,Cd?14??weresynthesizedfromtheligand5,5'-?biphenyl-4,4'-diylbis?methylene??bis?oxy?diisophthalic acid?H₄L?and transition metals.In the structure of the compounds 11-14,ligand L is decomposed in situ into carboxylic acid derived ligand?L¹ and L²?.Compounds 11-14 are the same 3D structures.Compounds 13 and 14 emit intense blue light under ultraviolet lamps,and we studied their fluorescence properties.Compound 13 exhibited fluorescence quenching effect on nitro compounds,while compound 14 exhibited quenching effect on organic solvents.