On the Role of Enthalpic and Entropic Contributions to the Conformational Free Energy Landscape of MIL-101(Cr) Secondary Building Units

Loukas Kollias, David C. Cantu, Vassiliki Alexandra Glezakou, Roger Rousseau, Matteo Salvalaglio

Research output: Contribution to journalArticle

Abstract

The thermo-structural behavior of metal-organic framework (MOF) precursors is responsible for regulating the introduction of defects in MOF structures during synthesis. In this paper, factors affecting the flexibility of MIL-101(Cr) half-secondary building units (half-SBUs) are evaluated in solution using enhanced sampling methods. In particular, entropic and enthalpic contributions to the conformational free energy landscape of isolated MIL-101(Cr) half-SBUs are calculated in water, in the presence and absence of ionic species (Na+ and F), and in N, N-dimethylformamide (DMF). This analysis leads to the observation that the interplay between enthalpy and entropy determines the most probable conformational state for half-SBUs. This observation extends to the most relevant SBU intermediate, in which conformational entropy plays a key role in stabilizing configurations that differ from those found in the MIL-101(Cr) crystal structure. The findings highlight the importance of explicitly considering entropic effects, associated with finite-temperature sampling when estimating the relative stability of different conformers of SBUs.

Original languageEnglish
JournalAdvanced Theory and Simulations
DOIs
Publication statusAccepted/In press - 2020

Keywords

  • entropy
  • metal-organic frameworks
  • molecular dynamics

ASJC Scopus subject areas

  • General
  • Modelling and Simulation
  • Numerical Analysis
  • Statistics and Probability

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