A Diazo Linker Ligand Promotes Flexibility and Induced Fit Binding in a Microporous Copper Coordination Network

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Xia Li - , Nankai University, University of Limerick (Author)
  • Debobroto Sensharma - , University of Limerick (Author)
  • Wells Graham - , Wake Forest University (Author)
  • Volodymyr Bon - , Chair of Inorganic Chemistry I (Author)
  • En Lin - , Nankai University (Author)
  • Xiang Jing Kong - , University of Limerick (Author)
  • Tao He - , University of Limerick (Author)
  • Andrey A. Bezrukov - , University of Limerick (Author)
  • Zhenjie Zhang - , Nankai University (Author)
  • Stefan Kaskel - , Chair of Inorganic Chemistry I (Author)
  • Timo Thonhauser - , Wake Forest University (Author)
  • Michael J. Zaworotko - , University of Limerick (Author)

Abstract

Flexible organic linkers represent an intuitive and effective strategy to design flexible metal–organic materials. We report herein a systematic study concerning the effect of varying the central bond of mixed pyridyl-benzoate linkers, L, upon the flexibility of three isostructural kdd topology microporous coordination networks (CNs) of formula ML2: X-kdd-1-Cu, 1 = L = (E)-4-(pyridin-4-yldiazenyl)benzoate; X-kdd-2-Cu, 2 = L = (E)-4-(2-(pyridin-4-yl)vinyl)benzoate; the previously reported X-kdd-3-Cu, 3 = L = 4-(pyridin-4-ylethynyl)benzoate. As revealed by single crystal x-ray diffraction (SCXRD) and gas sorption studies, X-kdd-1-Cu, exhibited gate-opening during CO2 and hydrocarbon (C2 and C8) sorption experiments whereas the other two CNs did not. Insight into these phase transformations was gained from in situ variable-pressure and variable temperature powder X-ray diffraction (PXRD), SCXRD, and modeling. Rotation of ligand 1 around the diazo bond, torsion angle changes between phenyl and carboxylate moieties, and deformation of the Cu-based rod building blocks enabled activated X-kdd-1-Cu to form new phases with C8 isomers and CH2Cl2, CH2Cl2 inducing contraction of the activated phase. Computational studies suggest that 1 enables flexibility thanks to its lower barrier of deformation versus 2 or 3. This study teaches that diazo moieties could offer a general strategy to enhance the flexibility of CNs.

Details

Original languageEnglish
Article numbere202507757
Number of pages9
JournalAngewandte Chemie - International Edition
Volume64 (2025)
Issue number31
Publication statusPublished - 28 Jul 2025
Peer-reviewedYes

Keywords

ASJC Scopus subject areas

Keywords

  • Azo bond, Flexible metal-organic materials, Host-guest chemistry, Induced fit