ABX3-Type Organic–Inorganic Hybrid Phase Transition Material: 1-Pentyl-3-methylimidazolium Tribromoplumbate

A new one-dimensional ABX3-type organic-inorganic hybrid phase transition compound, 1-pentyl-3-methylimidazolium tribromoplumbate (1), where the Pb(II) ion exhibits hemicoordination geometry, resulting in anionic (PbBr3)n chains of an edge-shared PbBr5 polyhedron, has been successfully synthesized. 1 undergoes a reversible second-order phase transition at about 136 K. The dielectric constants of 1 exhibit an obvious steplike anomaly tuned between a high dielectric state in the high-temperature phase and a low state in the low-temperature phase. The origin of its phase transition is ascribed to the order-disorder transformation of the cation coupled with the relative displacement of the Br atoms. These findings provide a new approach to exploring a novel ABX3-type compound with functional phase transition properties.