Firth, Francesca CN, Gaultois, Michael W 
ORCID: 0000-0003-2172-2507, Wu, Yue, Stratford, Joshua M, Keeble, Dean S, Grey, Clare P and Cliffe, Matthew J
(2021)
Exploring the Role of Cluster Formation in UiO Family Hf Metal-Organic Frameworks with <i>in Situ</i> X-ray Pair Distribution Function Analysis.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 143 (47).
pp. 19668-19683.
Abstract
The structures of Zr and Hf metal-organic frameworks (MOFs) are very sensitive to small changes in synthetic conditions. One key difference affecting the structure of UiO MOF phases is the shape and nuclearity of Zr or Hf metal clusters acting as nodes in the framework; although these clusters are crucial, their evolution during MOF synthesis is not fully understood. In this paper, we explore the nature of Hf metal clusters that form in different reaction solutions, including in a mixture of DMF, formic acid, and water. We show that the choice of solvent and reaction temperature in UiO MOF syntheses determines the cluster identity and hence the MOF structure. Using <i>in situ</i> X-ray pair distribution function measurements, we demonstrate that the evolution of different Hf cluster species can be tracked during UiO MOF synthesis, from solution stages to the full crystalline framework, and use our understanding to propose a formation mechanism for the <b>hcp</b> UiO-66(Hf) MOF, in which first the metal clusters aggregate from the M<sub>6</sub> cluster (as in <b>fcu</b> UiO-66) to the <b>hcp</b>-characteristic M<sub>12</sub> double cluster and, following this, the crystalline <b>hcp</b> framework forms. These insights pave the way toward rationally designing syntheses of as-yet unknown MOF structures, <i>via</i> tuning the synthesis conditions to select different cluster species.
| Item Type: | Article |
|---|---|
| Divisions: | Faculty of Science and Engineering > School of Physical Sciences |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 10 May 2022 12:26 |
| Last Modified: | 19 Oct 2023 08:49 |
| DOI: | 10.1021/jacs.1c06990 |
| Open Access URL: | https://pubs.acs.org/doi/10.1021/jacs.1c06990 |
| Related URLs: | |
| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3154557 |
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