Mechanical Tunability via Hydrogen Bonding in Metal–Organic Frameworks with the Perovskite Architecture

Two analogous metal–organic
frameworks (MOFs) with the perovskite
architecture, [C­(NH2)3]­[Mn­(HCOO)3] (1) and [(CH2)3NH2]­[Mn­(HCOO)3] (2), exhibit significantly different
mechanical properties. The marked difference is attributed to their
distinct modes of hydrogen bonding between the A-site amine cation
and the anionic framework. The stronger cross-linking hydrogen bonding
in 1 gives rise to Young’s moduli and hardnesses
that are up to twice those in 2, while the thermal expansion
is substantially smaller. This study presents clear evidence that
the mechanical properties of MOF materials can be substantially tuned
via hydrogen-bonding interactions.