Syntheses And Catalytic Properties Of Metal-Organic Frameworks Constructed From Porphyrin Ligands

Metal-organic frameworks?MOFs?,as a new class of porous material,have been quickly developed into a fruitful research field in the past decades.The introdiction of porphyrin or metalloporphyrin into MOFs can prepare novel materials with excellent excellent photoelectric and catalytic properties.In this paper,four MOFs constructed from three porphyrin ligand have been synthesized under solvothermal conditions.Each as-synthesized compound has unique structure and catalytic active sites.Based on the characteristics of each MOF,the catalytic performance toward different reactions were studied in detail.In addition,the general applicability and recyclability of MOFs were also explored.1.By using a new porphyrin-based linker 5,10,15,20-tetra?4-?3-?pyrazin-2-yl?-1H-pyrazo-1-yl?phenyl?porphyrin?H₂tppp?,two unusual mixed-valent Cu?I,II?-and Ag?I,II?-organic networks,namely,[Cu?I?6I6?Cu?II?-tppp?]·2DMF?1?and [Ag?I??NO3?0.5?Ag?II?-tppp?]·0.5NO3·DMF?2?,were successfully synthesized under solvothermal conditions.In 1,each Cu?II?-tppp ligands bridge six [Cu6I6] clusters to afford a charming 2D network.In 2,adjacent Ag?I?ions are linked by Ag?II?-tppp ligands into a unique 1D chain.Most strikingly,catalytic activities for the azide-alkyne cycloaddition reaction and oxidation of ethylbenzene were examined using catalysts 1 and 2.The catalytic results demonstrate that 1 has excellent catalytic capability for azide–alkyne cycloaddition and oxidation of ethylbenzene as a recycled heterogeneous catalyst.2.A new porous rtl MOF [Mn5L?H₂O?6·?DMA?2]·5DMA·4C2H5OH?3??H10L = 5,10,15,20-tetra?4-?3,5-dicarboxylphenoxy?-phenyl?porphyrin and DMA = N,N'-dimethylacetamide?was synthesized by employing a new porphyrin-based octacarboxylic acid ligand.3 exhibits high Mn?II?density in the porous framework,providing it great Lewis-acid heterogeneous catalytic capability for the cycloaddition of CO₂ with epoxides under atmospheric and high pressure.Strikingly,3 features excellent catalytic activity to the cycloaddition of CO₂ to epoxides under 20 atm,with a remarkable initial turnover frequency 400 per mole of catalyst per hour at 20 atm.The synthesized 3 also exhibits size selectivity to different epoxide substrates on account of their steric hindrance.3.A porous 4-fold interpenetrated mog MOF [Cd3?tipp??bpdc?2]·DMA·9H₂O?4??H₂tipp = 5,10,15,20-tetra?4-?imidazol-1-yl?phenyl?porphyrin,H₂ bpdc = biphenyl-4,4'-dicarboxylic acid?has been synthesized under solvothermal conditions.The incorporation of Cd and carboxylate oxygen affords 4 rich Lewis acid and basic sites.Such MOF 4 was then applied as an efficient heterogeneous catalyst for the cyanosilylation of aldehydes and Knoevenagel condensation reactions.4 features substrate selectivity and recyclability for the both C-C bond formation reactions.