Synthesis, crystal structure and disorder–order phase transition of a new diamine templated metal sulfate, (C3H12N2)2[Cu(H2O)4(SO4)2](HSO4)2

Abstract

An inorganic–organic hybrid compound, (C₃H₁₂N₂)₂[Cu(H₂O)₄(SO₄)₂](HSO₄)₂ (1), was synthesized by slow evaporation based on 1,3-propanediamine as the template. Differential scanning calorimetry measurement showed that compound 1 underwent a reversible phase transition at 277 K with a hysteresis width of 3 K. The temperature dependence of the dielectric permittivity also confirmed the phase transition. Single crystal X-ray diffraction demonstrated that the disorder–order transformation of the C atoms in the (C₃H₁₂N₂)²⁺ cation may drive the structural phase transition. The dielectric permittivity of 1 can be switched between two states, which will be used in switchable dielectric devices.