Reversible Switching between Nonporous and Porous Phases of a New SIFSIX Coordination Network Induced by a Flexible Linker Ligand

Published

April 15, 2020

Author(s)

Bai-Qiao Song, Qing-Yuan Yang, Shi-Qiang Wang, Matthias Vandichel, Amrit Kumar, Clare Crowley, Naveen Kumar, Cheng-Hua Deng, Victoria GasconPerez, Matteo Lusi, Hui Wu, Wei Zhou, Michael J. Zaworotko

Abstract

Closed-to-open structural transformations in flexible coordination networks are of interest for their potential utility in gas storage and separation. Herein, we report the first example of a flexible SiF₆^2--pillared square grid material, [Cu(SiF₆)(L)₂]_n (L = 1,4-bis(1-imidazolyl)benzene), SIFSIX-23-Cu. SIFSIX-23-Cu exhibits reversible switching between nonporous (β1) and several porous (α, γ1, γ2 and γ3) phases triggered by exposure to N₂, CO₂ or H₂O. In addition, heating β1 to 433 K resulted in irreversible transformation to a closed polymorph, β2. Single-crystal X-ray diffraction (SCXRD) studies revealed that the reversible switching is enabled by a hinge-like motion from rotation and geometrical contortion of L and bending at metal-L coordination sites. The irreversible transformation was accompanied by anti-to-syn isomerization of L and a swing motion of SIFSIX pillars. In situ neutron powder diffraction studies provided insight into these sorbate-induced phase changes. SIFSIX-23-Cu combines stability in water for a year, high CO₂ uptake (ca. 216 cm³/g, 195 K) and good thermal stability.

Citation

Journal of the American Chemical Society

Volume

142

Issue

15

Pub Type

Journals

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Keywords

Porous material, Phase transition, Gas storage

Citation

Song, B. , Yang, Q. , Wang, S. , Vandichel, M. , Kumar, A. , Crowley, C. , Kumar, N. , Deng, C. , GasconPerez, V. , Lusi, M. , Wu, H. , Zhou, W. and Zaworotko, M. (2020), Reversible Switching between Nonporous and Porous Phases of a New SIFSIX Coordination Network Induced by a Flexible Linker Ligand, Journal of the American Chemical Society, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=929753 (Accessed October 21, 2025)