A Porous Coordination‐Polymer Crystal Containing One‐Dimensional Water Chains Exhibits Guest‐Induced Lattice Distortion and a Dielectric Anomaly

Ice one : A porous molecular crystal with guest water molecules in the channels—[La 2 Cu 3 {NH(CH 2 COO) 2 } 6 ](H 2 O) n (see picture)—exhibits a distinct peak for the dielectric constant at 180 K ( ε r ≈150) with the electric field parallel to the channel direction. This crystalline compound also shows a large enhancement of ε r above 250 K and a characteristic antiferroelectric hysteresis coupled with a liquid–solid transition of the guest water molecules at around 350 K.