A square-pyramidal coordinated copper(ii) hydrazine dimeric complex showing reversible phase transition, dielectric anomaly and thermochromism

Abstract

Recently, the development of multifunctional thermochromic materials that exhibit switching characteristics in phase transition and dielectric properties has attracted widespread attention due to their potential application in signal processing and smart devices. But most traditional thermochromic materials tend to be rather than reversible phase change materials. Here, a square-pyramidal coordinated copper complex [Me₃NNH₂CuCl₃]₂ (1) (Me₃NNH₂ = trimethyl hydrazine) showing switchable properties in phase transition, dielectricity and thermochromic properties has been prepared by reaction of Me₃NNH₂I with CuCl₂ in concentrated HCl aqueous solution. Compound 1 has a reversible phase transition temperature of 45 °C. When the temperature exceeds the phase transition temperature, the green color of 1 gradually changed into dark red. Compared with traditional thermochromic materials, the reversible phase transition and dielectric properties within the thermochromic materials will bring additional spectral encryption possibilities for future information processing.