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How Can a Hydrophobic MOF be Water‐Unstable? Insight into the Hydration Mechanism of IRMOFs
Author(s) -
De Toni Marta,
Jonchiere Romain,
Pullumbi Pluton,
Coudert FrançoisXavier,
Fuchs Alain H.
Publication year - 2012
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201200455
Subject(s) - physisorption , chemistry , chemical physics , bound water , molecule , cluster (spacecraft) , molecular dynamics , linker , crystallography , computational chemistry , adsorption , organic chemistry , computer science , programming language , operating system
We report an ab initio molecular dynamics study of the hydration process in a model IRMOF material. At low water content (one molecule per unit cell), water physisorption is observed on the zinc cation but the free⇄bound equilibrium strongly favors the free state. This is consistent with the hydrophobic nature of the host matrix and its type‐V isotherm observed in a classical Monte Carlo simulation. At higher loading, a water cluster can be formed at the Zn 4 O site and this is shown to stabilize the water‐bound state. This structure rapidly transforms into a linker‐displaced state, where water has fully displaced one arm of a linker and which corresponds to the loss of the material’s fully ordered structure. Thus an overall hydrophobic MOF material can also become water unstable, a feature that has not been fully understood until now.