Direct X-ray observation of trapped CO2 in a predesigned porphyrinic metal-organic framework

Jacob A. Johnson, Shuang Chen, Tyler C. Reeson, Yu Sheng Chen, Xiao Cheng Zeng, Jian Zhang

Research output: Contribution to journalArticlepeer-review

40 Scopus citations


Metal-organic frameworks (MOFs) are emerging microporous materials that are promising for capture and sequestration of CO2 due to their tailorable binding properties. However, it remains a grand challenge to pre-design a MOF with a precise, multivalent binding environment at the molecular level to enhance CO2 capture. Here, we report the design, synthesis, and direct X-ray crystallographic observation of a porphyrinic MOF, UNLPF-2, that contains CO2-specific single molecular traps. Assembled from an octatopic porphyrin ligand with [Co2(COO)4] paddlewheel clusters, UNLPF-2 provides an appropriate distance between the coordinatively unsaturated metal centers, which serve as the ideal binding sites for in situ generated CO2. The coordination of CoII in the porphyrin macrocycle is crucial and responsible for the formation of the required topology to trap CO2. By repeatedly releasing and recapturing CO2, UNLPL-2 also exhibits recyclability. CO 2-Specific traps are generated in a rationally designed porphyrinic MOF, UNLPF-2 (see figure). With a precise binding environment, CO2 trapping is directly observed by X-ray crystallography. More remarkably, UNLPF-2 can repeatedly release and recapture CO2, exhibiting a good recyclability.

Original languageEnglish (US)
Pages (from-to)7632-7637
Number of pages6
JournalChemistry - A European Journal
Issue number25
StatePublished - Jun 16 2014


  • carbon dioxide
  • carboxylate ligands
  • metal-organic frameworks
  • porous materials
  • porphyrins

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry


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