Poster Presentation The 35th Biennial Conference of the Society of Crystallographers in Australia and New Zealand 2024 (Crystal 35)

Water cluster structure in the MOF CAU-10-X (X = H, OH): a powder diffraction perspective (#221)

Gwilherm Nénert 1 , Stefano Canossa 2 , Davide Rega 3 , Olga Narygina 4 , Monique A. van der Veen 3
  1. Malvern Panalytical B.V., Almelo, the Netherlands
  2. Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, Switzerland
  3. Department of Chemical Engineering, TU Delft, Delft, the Netherlands
  4. Malvern Panalytical, a division of Spectris Australia Pty Ltd, Chipping Norton, NSW, Australia

Several metal-organic frameworks (MOF) excel in harvesting water from the air or as heat pumps as they show a steep step in the water isotherm at 10-30 RH%[1]. Yet, a precise understanding of the water structure within the confined space of such MOF is still lacking. Here, we unravel the structural properties of CAU-10-H under various water content. We show that the water content can be tuned using the relative humidity, temperature, and history of the sample. Previous studies have shown a structural phase transition from hydrated (non-centrosymmetric structure) to dry (centrosymmetric structure)[2]. In this contribution, we show that high resolution powder diffraction allows to locate water molecules and detect the existence of various states of hydrated phases including centrosymmetric one. Besides bringing further insight into the water clusters present in the MOF the study demonstrates the powerfulness of powder diffraction in the analysis of MOF materials.

  1. [1] Wentao, X., and Yaghi, O. M., (2020). ACS Cent. Sci., 6(8), 1348.
  2. [2] Fröhlich, D., et al. (2016). J. Mater. Chem. A, 4, 11859.