Cryo-EM structures of atomic surfaces and host-guest chemistry in metal-organic frameworks

Yuzhang Li; Kecheng Wang; Weijiang Zhou; Yanbin Li; Rafael Vila; William Huang; Hongxia Wang; Guangxu Chen; Gong-Her Wu; Yuchi Tsao; Hansen Wang; Robert Sinclair; Wah Chiu; Yi Cui

doi:10.1016/j.matt.2019.06.001

Cryo-EM structures of atomic surfaces and host-guest chemistry in metal-organic frameworks

Matter. 2019 Aug 7;1(2):428-438. doi: 10.1016/j.matt.2019.06.001. Epub 2020 Mar 24.

Authors

Yuzhang Li¹, Kecheng Wang¹, Weijiang Zhou², Yanbin Li¹, Rafael Vila¹, William Huang¹, Hongxia Wang¹, Guangxu Chen¹, Gong-Her Wu³, Yuchi Tsao⁴, Hansen Wang¹, Robert Sinclair¹, Wah Chiu^{2

3

5

6}, Yi Cui^{1

7}

Affiliations

¹ Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
² Biophysics Program, School of Medicine, Stanford University, Stanford, California 94305, USA.
³ Department of Bioengineering, Stanford University, Stanford, California 94305, USA.
⁴ Department of Chemistry, Stanford University, Stanford, California 94305, USA.
⁵ Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305, USA.
⁶ Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
⁷ Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.

Abstract

Host-guest interactions govern the chemistry of a broad range of functional materials, but direct imaging using conventional transmission electron microscopy (TEM) has not been possible. This problem is exacerbated in metal-organic framework (MOF) materials, which are easily damaged by the electron beam. Here, we use cryogenic-electron microscopy (cryo-EM) to stabilize the host-guest structure and resolve the atomic surface of zeolitic imidazolate framework (ZIF-8) and its interaction with guest CO₂ molecules. We image step-edge sites on the ZIF-8 surface that provides insight to its growth behavior. Furthermore, we observe two distinct binding sites for CO₂ within the ZIF-8 pore, which are predicted by density functional theory (DFT) to be energetically favorable. This CO₂ insertion induces an apparent ~3% lattice expansion along the <002> and <011> directions of the ZIF-8 unit cell. The ability to stabilize and preserve host-guest chemistry opens a rich materials space for scientific exploration and discovery using cryo-EM.

Abstract

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