Intrinsic flexibility of the EMT zeolite framework under pressure

Antony Nearchou, Mero Lee U. Cornelius, Jonathan M. Skelton, Zöe L. Jones, Andrew B. Cairns, Ines E. Collings, Paul R. Raithby, Stephen A. Wells, Asel Sartbaeva

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

The roles of organic additives in the assembly and crystallisation of zeolites are still not fully understood. This is important when attempting to prepare novel frameworks to produce new zeolites. We consider 18-crown-6 ether (18C6) as an additive, which has previously been shown to differentiate between the zeolite EMC-2 (EMT) and faujasite (FAU) frameworks. However, it is unclear whether this distinction is dictated by influences on the metastable free-energy landscape or geometric templating. Using high-pressure synchrotron X-ray diffraction, we have observed that the presence of 18C6 does not impact the EMT framework flexibility—agreeing with our previous geometric simulations and suggesting that 18C6 does not behave as a geometric template. This was further studied by computational modelling using solid-state density-functional theory and lattice dynamics calculations. It is shown that the lattice energy of FAU is lower than EMT, but is strongly impacted by the presence of solvent/guest molecules in the framework. Furthermore, the EMT topology possesses a greater vibrational entropy and is stabilised by free energy at a finite temperature. Overall, these findings demonstrate that the role of the 18C6 additive is to influence the free energy of crystallisation to assemble the EMT framework as opposed to FAU.

Original languageEnglish
Article number641
JournalMolecules
Volume24
Issue number3
DOIs
Publication statusPublished - 12 Feb 2019

Keywords

  • Compressibility
  • Crystallization
  • EMC-2
  • Flexibility window
  • Framework materials
  • High pressure
  • Lattice dynamics
  • X-ray diffraction
  • Zeolite

ASJC Scopus subject areas

  • Analytical Chemistry
  • Chemistry (miscellaneous)
  • Molecular Medicine
  • Pharmaceutical Science
  • Drug Discovery
  • Physical and Theoretical Chemistry
  • Organic Chemistry

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Dataset for "Intrinsic flexibility of the EMT zeolite framework under pressure"

Nearchou, A. (Creator), Cornelius, M. (Creator), Skelton, J. (Creator), Jones, Z. (Contributor), Cairns, A. (Contributor), Collings, I. (Contributor), Raithby, P. (Project Leader), Wells, S. (Other) & Sartbaeva, A. (Project Leader), University of Bath, 12 Feb 2019

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  • Cite this

    Nearchou, A., Cornelius, M. L. U., Skelton, J. M., Jones, Z. L., Cairns, A. B., Collings, I. E., Raithby, P. R., Wells, S. A., & Sartbaeva, A. (2019). Intrinsic flexibility of the EMT zeolite framework under pressure. Molecules, 24(3), [641]. https://doi.org/10.3390/molecules24030641