Organic Counteranion Co-assembly Strategy for the Formation of γ-Cyclodextrin-Containing Hybrid Frameworks

Dengke Shen, James A. Cooper, Peng Li, Qing Hui Guo, Kang Cai, Xingjie Wang, Huang Wu, Hongliang Chen, Long Zhang, Yang Jiao, Yunyan Qiu, Charlotte L. Stern, Zhichang Liu, Andrew C.H. Sue, Ying Wei Yang, Fehaid M. Alsubaie, Omar K. Farha, J. Fraser Stoddart*

*Corresponding author for this work

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

A class of γ-cyclodextrin-containing hybrid frameworks (CD-HFs) has been synthesized, employing γ-cyclodextrin (γ-CD) as the primary building blocks, along with 4-methoxysalicylate (4-MS-) anions as the secondary building blocks. CD-HFs are constructed through the synergistic exploitation of coordinative, electrostatic, and dispersive forces. The syntheses have been carried out using an organic counteranion co-assembly strategy, which allows for the introduction of 4-MS-, in place of inorganic OH-, into the cationic γ-CD-containing metal-organic frameworks (CD-MOFs). Although the packing arrangement of the γ-CD tori in the solid-state superstructure of CD-HFs is identical to that of the previously reported CD-MOFs, CD-HFs crystallize with lower symmetry and in the cuboid space group P43212 - when compared to CD-MOF-1, which has the cubic unit cell of I432 space group - on account of the chiral packing of the 4-MS- anions in the CD-HF superstructures. Importantly, CD-HFs have ultramicroporous apertures associated with the pore channels, a significant deviation from CD-MOF-1, as a consequence of the contribution from the 4-MS- anions, which serve as supramolecular baffles. In gas adsorption-desorption experiments, CD-HF-1 exhibits a Brunauer-Emmett-Teller (BET) surface area of 306 m2 g-1 for CO2 at 195 K, yet does not uptake N2 at 77 K, confirming the difference in porosity between CD-HF-1 and CD-MOF-1. Furthermore, the 4-MS- anions in CD-HF-1 can be exchanged with OH- anions, leading to an irreversible single-crystal to single-crystal transformation, with rearrangement of coordinated metal ions. Reversible transformations were also observed in CD-MOF-1 when OH- ions were exchanged for 4-MS- anions, with the space group changing from I432 to R32. This organic counteranion co-assembly strategy opens up new routes for the construction of hybrid frameworks, which are inaccessible by existing de novo MOF assembly methodologies.

Original languageEnglish (US)
Pages (from-to)2042-2050
Number of pages9
JournalJournal of the American Chemical Society
Volume142
Issue number4
DOIs
StatePublished - Jan 29 2020

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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    Shen, D., Cooper, J. A., Li, P., Guo, Q. H., Cai, K., Wang, X., Wu, H., Chen, H., Zhang, L., Jiao, Y., Qiu, Y., Stern, C. L., Liu, Z., Sue, A. C. H., Yang, Y. W., Alsubaie, F. M., Farha, O. K., & Stoddart, J. F. (2020). Organic Counteranion Co-assembly Strategy for the Formation of γ-Cyclodextrin-Containing Hybrid Frameworks. Journal of the American Chemical Society, 142(4), 2042-2050. https://doi.org/10.1021/jacs.9b12527