Synthesis Of Terpyridyl Metal-organic Frameworks (MOFs) And Applications In Detection And Catalysis

In recent years,metal-organic framework(MOFs)materials with functionalized reactive groups have attracted extensive attention by scientists.However,most N and O donor atoms of nitrogen-containing heterocyclic rings,polycarboxylic acids and heterocyclic polycarboxylic acid ligands are coordinated with metal ions during the assembly of MOFs,which is not conducive to the post-functionalization of MOFs materials.In this paper,the 3(4)-pyridine ring functionalized terpyridine polycarboxylic acid ligands were synthesized by cyclization reaction using2-acetylpyridine methyl 4-formate as raw materials by introducing carboxylic groups on both sides of the terpyridine ring.And a series of low dimensional metal-organic frameworks(MOF-S1?S5)and a mononuclear complex(SCC-S1)functionalized carboxyl or pyridine ring were constructed by the reaction of M2MTP and M2PTP with transition metal salts.With the machinability of low-dimensional MOFs and the subsequent reactivity of functional MOFs,the colloidal fluorescent probe of nanosheets was obtained,which can sense the novel pesticides with the high sensitivity.At the same time,non-noble heterometallic catalysts with superior performance were also obtained,which can catalyze in situ hydrohydrolysis of vanillin and oxidation of benzyl alcohol effectively.The specific research work is as follows.(1)Two ligands(M2PTP and M2MTP)were synthesized from methyl2-acetylpyridine-4-formate and pyridine-3-formaldehyde(pyridine-4-formaldehyde).With these ligands,five low dimensional MOFs(MOF-S1?S5)and a mononuclear complex(SCC-S1)were synthesized.The data from single crystal X-ray diffraction of them confirmed that MOF-S1?S5 are composed of 2D Zn coordination layer,1D Cu coordination chain,2D double Cu coordination layer,2D Cu coordination layer and1D zigzag Mn coordination chain,respectively.The as-synthesized MOFs and SCC-S1 possess uncoordinated carboxyl or pyridine N,which will be beneficial for the post-functional application of MOFs.(2)MOF-S1 is a three-dimensional structure connected by hydrogen bonds and?-?interactions between coordination layers.In this paper,the bulk MOF-S1 was successfully exfoliated into two-dimensional nanosheets by a simple treatment method of ultrasound.Since MOF-S1 has uncoordinated pyridine N,it may interact with pesticide molecules to generate fluorescence response.In this paper,the exfoliated two-dimensional nanosheets were used to make a colloidal system as a pesticide sensor.It was proved by experiments that the two-dimensional MOF-S1nanosheet colloidal sensing system had high sensitivity to nitro-neonicotinoids,and was sensitive to imidacloprid,dinotefuran The detection limits for amine and nitenpyram were 0.562,0.247,and 0.441?M,respectively.(3)SCC-S1 is a mononuclear complex with tpy-Fe-tpy node,and the carboxyl groups of PTP^2-ligands are uncoordinated,which can bond other metals to afford the mixed-metal MOFs.In this paper,metal-mixed MOFs were obtained by bonding other metals with SCC-S1,and then a series of non-noble heterometallic MOFs-derived catalysts(M-Fe-T and M-Fe-TH:M=Cu,Zn,Co,Ni,etc;T represents the calcination temperature;H represents hydrogen activation treatment)were obtained by calcination.The performance of the catalysts was investigated using the oxidation of benzyl alcohol and the reduction of vanillin as the model reactions.The experimental results showed that the conversion of benzyl alcohol was 99%and the selectivity of methyl benzoate was 87%with Co-Fe-700 as the catalysts in the experiment of oxidizing benzyl alcohol with molecular oxygen as the oxidant at120? for 6 h.The same high conversion rate was obtained when catalyzing the oxidation of other aromatic alcohols.Cu-Fe-700H exhibited excellent catalytic performance in catalyzing the in situ hydrogenolysis of vanillin using isopropanol as hydrogen source.The selectivity of methyl-guaiacol reached 92.2%.