Porous Metal-organic Framework Materials Constructed From Ligand With C₃Symmetry

Metal-organic frameworks （MOFs） is refers to periodical network thatconstructed from metal ions and organic ligands through self-assembly. It has beenpaid more attention because of its various topology structures and the potentialapplication in the fields of gas storage, gas separation, catalytic, optical and magneticproperties, and so on. Especially, the carboxylic acid ligand with symmetry of C3receiving more and more attention because it can form MOFs with large pore size andhigh surface area by coordination with metal ion. In this paper, we have designed andsynthesized a carboxylic acid ligand with symmetry of C3, and have obtained threeMOFs by using it basic building unit to coordinate with zinc nitrate, cobalt chlorideand cadmium nitrate. Apart from this, we also obtained another three coordinatepolymers by using1,3,5-Benzenetricarboxylic acid react with nickel chloride,manganese acetate and manganese chloride. We summaries and analyzes some rulesin the process of synthesis, and the properties are analyzed selective. This paper isdivided into five parts:In the first part, we systematically introduced not only the basic conception,history, development, synthesis methods and the influence factors, but also theapplication of the coordination polymers and given our aims in this topic.In the second part, we showed how to synthesis a carboxylic ligand with C3symmetry which named2,4,6-tri（4-carboxyphenyl）pyridine and its modified product2,4,6-tri（4-carboxyphenyl）pyridine triethylcarboxylate from4-methylbenzaldehydeand4-methylacetophenone. We have succeeded in getting a pyridine derivative byusing nine amines in a solvent-free method, maybe provide a new process forsynthesis pyridine derivatives, and then we got the corresponding carboxylic acidusing two oxidation method. All the products of each step have been character by IRand1H NMR, and the crystal structures of2,4,6-tri（4-carboxyphenyl）pyridine and itsmodified product2,4,6-tri（4-carboxyphenyl）pyridine triethylcarboxylate wereconfirmed by single X-ray.In the third section, we use2,4,6-tri（4-carboxyphenyl）pyridine react with zinc nitrate, cobalt chloride and cadmium nitrate, and successfully obtained three MOFs.The Zn₃O（HPTB）₂（H₂O） has rhombus channel in c axis and circular channel in a axis,but the Co₃O（HPTB）₂（H₂O） has rhombus channel in a axis and rectangle channel in baxis, more interesting is the Cd3（PTB）3（DMF）8has bilayer structure. And then wecharacter them by single crystal X-ray, power XRD and TG. Last we summarizes theligand symmetry can influence the symmetry of the structure by comparing theZn₃O（HPTB）₂（H₂O） to the reported MOF-39.In the fourth part, we get three coordination polymers from BTC react withnickel chloride, manganese acetate and manganese chloride, and characterized bysingle crystal X-ray, power XRD, TG and magnetic. In especial, we preparednanometer level layered coordination polymers from the product which obtained fromBTC react with nickel chloride, and characterized by power XRD and SEM.Finally, the method of synthesis2,4,6-tri（4-carboxyphenyl）pyridine besummarized, and compared the obtained coordination polymers to the reportedMOF-39. Last we not only summarizes the ligand symmetry can influence thesymmetry of the structure but also other factor, such as deprotonation agent, solventand metal salt, and so on.