ja411673b_si_001.pdf (1.4 MB)
On the Flexibility of Metal–Organic Frameworks
journal contribution
posted on 2014-02-12, 00:00 authored by Lev Sarkisov, Richard
L. Martin, Maciej Haranczyk, Berend SmitOccasional,
large amplitude flexibility in metal–organic
frameworks (MOFs) is one of the most intriguing recent discoveries
in chemistry and material science. Yet, there is at present no theoretical
framework that permits the identification of flexible structures in
the rapidly expanding universe of MOFs. Here, we propose a simple
method to predict whether a MOF is flexible, based on treating it
as a system of rigid elements, connected by hinges. This proposition
is correct in application to MOFs based on rigid carboxylate linkers.
We validate the method by correctly classifying known experimental
MOFs into rigid and flexible groups. Applied to hypothetical MOFs,
the method reveals an abundance of flexibility phenomena, and this
seems to be at odds with the proportion of flexible structures among
experimentally known MOFs. We speculate that the flexibility of a
MOF may constitute an intrinsic impediment on its experimental realization.
This highlights the importance of systematic prediction of large amplitude
flexibility regimes in MOFs.