| Metal-organic frameworks(MOFs)are a series of multi-functional crystalline materials with novel structures,which are combined by metal ions or metal clusters and organic ligands for self-assembly.These materials possess large surface area and different pore size distribution and can synthesize with different organic groups,which make them obtain more and more attention in many aspects,such as gas adsorption and separation,gas storage,catalysis,magnetic properties,small molecules sensing,batteries,etc.Now,how to design and predict the structure of the metal-organic framework we need is still challenging.The choices of metal cations and ligands,the mixing conditions of the selected mixed solvents,the acid-base environment of the overall system,the temperature conditions for the synthesized materials,etc.are critical to the degrees of crystallization and crystal structures.Many works are focused on getting the desired target products to meet the material characteristics required for practical applications.At the same time,due to the presences of the pores in the MOFs materials,it is possible to introduce the guest molecules into the channels to synthesize the composites,which greatly improve the performances of the composites in different fields.However,there are still many problems in the fields of MOFs that are worthy of our exploration,such as how the framework achieves higher stability,the objective factors that affect the amount of gas adsorption,and the interactions between the host and guest frameworks for the potential application of predicting material in different areas.In this paper,twelve kinds of metal-organic frameworks were synthesized by different metal ions and different organic ligands.Their designs and syntheses,small molecules sensing and mercury ion detection,conductivity,dye adsorption and separation,detection of explosives were studied.1.Five new coordination polymers,compounds 1-5,were synthesized using different metal ions,1,4-naphthalene dicarboxylic acid and N-containing ligands.The diversities of the structures of the five compounds demonstrate that the 1,4-naphthalene dicarboxylic acid can be further formed as a multifunctional structural unit.And in the process of syntheses,the choices of ligand,and the systems of pH will be crucial to the synthesized coordination polymers.In addition,compound 3 exhibits an antiferromagnetic interaction between adjacent copper ions,and compound 4 represents the antiferromagnetic interaction between Co(II)ions and the presence spin orbit coupling.The solid-state fluorescence spectra show that compounds 1,2 and 5 have a strong emission at room temperature.[Cd2(1,4-ndc)2(bpy)2]·0.5H2O(1)[Cd(1,4-ndc)(phen)]·0.5H2O(2)[Cu2(1,4-ndc)2(L1)]·H2O(3)[Co3(H2O)2(1,4-ndc)4(HL2)2](4)[Cd2(L3)2(1,4-H2ndc)]·H2O(5)L1 =(1,2,4-triazol-1-yl)propane,L2 = 1,6-bis(imidazole)hexane,L3 =4,4'-bis(1H-imidazol-1-yl),1,4-H2 ndc = 1,4-naphthalene dicarboxylic acid2.In this chapter,a stable metal-organic framework,compound 6 was synthesized by solvothermal method.The structure of the compound shows a three-dimensional porous structure.At the same time,the compound also exhibits good chemical stability and thermal stability,can be stable up to 400 °C,and can withstand acid and alkaline solution.Meanwhile,the compound can efficiently detect small molecules and can be used as a fluorescent probe to selectively detect certain explosives and divalent mercury ions.[Cd(BPDC)0.5(L1)(NO3)]·3.4DMF(6)BPDC = 4,4'-biphenyldicarboxylic acid;L1 = 1-(3,5-bis(1H-imidazol-1-yl)phenyl)-1H-imidazole)3.In this paper,we synthesized a stable,highly conductive three-dimensional supramolecular structure,[Ag(H2O)(2,6-ndc)0.5(L)0.5]n(7),and carried out some basic characterizations.The material has an excellent electrical conductivity.Because of the presence of Ag(I)ions in the structure,it has fluorescence properties,and further confirmed that the compound can be used as a fluorescent probe to effectively detect the dichloromethane molecules.4.We selected a new ligand,that is,1-(1-(1H-imidazol-1-yl)naphthalen-4-yl)-1H-imidazole and 1,4-naphthalenedicarboxylic acid ligands to synthesize a stable three-dimensional metal-organic framework material,namely [Cu4(1,4-ndc)4(L)2]·H2O·2DMF(8).The structure of compound 8 can be considered as a two-fold interpenetrating pcu network structure constructed by binuclear {Cu2} units.At the same time,compound 8 is an excellent material that can be used to separate Rhodamine B(RB)and Methylene Blue(MB)dye molecules.In addition,compound 8 is an antiferromagnetic material.5.In conclusion,four MOFs with different topologies have been synthesized in this chapter by using tricyclic rigid ligands tib and different carboxylic acid ligands.They show different structural features.The fluorescent properties of compounds 9 and 10 mean that these two materials can be used to detect some explosives or explosives-like,such as NB and TNP,with good sensitivity and selectivity,and they are excellent fluorescent probes.Meanwhile,compounds 11 and 12 are antiferromagnetic materials.[Cd2(tib)(btb)(H2O)2]·NO3·DMF(9),[(CH3)2NH2][Cd(tib)(H2dhbqdc)0.5(NO3)]·2H2O(10),[Co(tib)(1,4-ndc)]·2DMF(11),[Cu1.5(tib)(2,6-ndc)]·NO3·H2O(12)tib = 1,3,5-tris(1-imidazolyl)benzene;btb = 1,3,5-benzenetribenzoic acid;H4dhbqdc =3,6-dihydroxy-2,5-benzoquinone-dicarboxylic acid;1,4-H2 ndc = 1,4-naphthalenedicarboxylic acid;2,6-H2 ndc = 2,6-naphthalene dicarboxylic acid... |
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