Dynamics of Water Molecules in a 3‑Fold Interpenetrated Hydrogen-Bonded Organic Framework Based on Tetrakis(4-pyridyl)methane

The
3-fold interpenetration of the β-quartz-type hydrogen-bonded
organic framework (HOF) from the dication salts of tetrakis­(4-pyridyl)­methane
develops a host–guest system featuring flexibility and durability
in accordance with the state change of guest molecules. Water molecules
are incorporated into HOF and form a one-dimensional helical-shaped
molecular chain in nanopores. X-ray crystallographic analysis and
the dielectric dispersion in the impedance measurements revealed that
guest water molecules behave dynamically and show a concerted freezing
process to produce water pentamers at 100 K. Structural changes in
the host framework mediate interactions between guest water molecules
within and between the nanopores through the weak host–guest
interactions based on hydrogen-bonding interaction. In addition, the
triangular arrangement of nanopores gives rise to the topologically
unsettled guest molecules in the freezing process.