Structural Phase Transition Of The Perovskite-like Azido Coordin-ation Polymers Based On Tetramethyl Ammonium Guest

The polarization behavior of the guest molecules/ions in confinement environments andtheir response to external stimulus is the source of some molecular-based functional materials.As a type of host-guest compounds with unique structure, perovskite-like coordinationpolymers (CPs) are good candidate for the study of the polarization behavior of the guestcation in the well-designed cage-like frameworks. Upon external stimulus such as temperatureor pressure, the induced order disorder change of the guest cation in the cage-like frameworksmay be the dominant driving force for structural phase transition. However, up to now, reportsabout such CPs remain very scarce.In this contribution, we are interested in searching new types of structural phasetransition materials in the perovskite-like CPs, and studying the molecular thermal motionbehavior of the guest cation in the well-designed cage-like frameworks. We selected azide asthe ligand, and tetramethyl ammonium as the cation guest. Our efforts have yielded a series ofperovskite-like azido coordination polymers, namely,(NMe4)[Cd(N3)3](1),(NMe4)2[CrNa(N3)6](2),(NMe4)2[CrK(N3)6](3),(NMe4)2[FeNa(N3)6](4), and (NMe4)2[FeK(N3)6](5).Through the studies on the structures and phase transition mechanism of these perovskite-likeCPs, we have a more in-depth understanding on the assembly of the perovskite-like azido CPs andtheir related properties.