Inorganic–organic hybrid compound with face-sharing iodoplumbate chains showing novel dielectric relaxation

An inorganic–organic hybrid compound, [4′-methyl-1-aminopyridinium][PbI3] (1), has been synthesized and characterized structurally. The hybrid crystal crystallizes in space group P21/c, in which the Pb2 + ion, surrounded by six iodides, adopts the distorted octahedral coordination geometry; the neighboring PbI6 octahedra form the face-sharing PbI6 octahedral chain and the organic cations are aligned into stack along c-axis direction. Hybrid compound shows normal dielectric constant (ε′ < 20) below 130 °C in the frequency range of 1–107 Hz, but higher dielectric constant above 160 °C, especially, in the low-frequency regime. In addition, a novel dielectric relaxation process was observed in the frequency regime f < 106 Hz, which exhibits the characteristic activated or Arrhenius behavior, such a dielectric relaxation process ARISES from the dynamically dipole motion of the 4′-methyl-1-aminopyridinium cations under ac electrical field.