  By virtue of their open network structures and low densities, metal--organic
frameworks (MOFs) are soft materials that exhibit elastic instabilities at low
applied stresses. The conventional strategy for improving elastic stability is
to increase the connectivity of the underlying MOF network, which necessarily
increases material density and reduces porosity. Here we demonstrate an
alternative paradigm, whereby elastic stability is enhanced in a MOF with an
aperiodic network topology. We use a combination of variable-pressure
single-crystal X-ray diffraction measurements and coarse-grained
lattice-dynamical calculations to interrogate the high-pressure behaviour of
the topologically aperiodic system TRUMOF-1, which we compare against that of
its ordered congener MOF-5. We show that the topology of the former quenches
the elastic instability responsible for pressure-induced framework collapse in
the latter, much as irregularity in the shapes and sizes of stones acts to
prevent cooperative mechanical failure in drystone walls. Our results establish
aperiodicity as a counterintuitive design motif in engineering the mechanical
properties of framework structures, relevant to MOFs and larger-scale
architectures alike.
