二乙胺四氯合铜相变的FTIR和2D-COS分析

Thermochromic Process of[(C_2H_5)2NH_2]_2CuCl_4 Probing by FTIR and 2D-COS Analysis

具有热致变色性能的化合物二乙胺四氯合铜[(C_2H_5)2NH_2]_2CuCl_4在52℃附近发生从绿色变为黄色的热致变色现象。本文采用傅里叶变换红外光谱(FTIR)和二维相关性分析(2D-COS)研究在加热和冷却过程中相转变过程中有机部分的铵离子和乙基所起的作用。随着温度的升高,分子中产生N—H…Cl氢键的强度减弱和烷基链的热扰动两种作用。2D-COS分析表明N—H…Cl氢键首先对温度升高有反应,可能作为[CuCl_4]^(2-)阴离子结构变化的主导驱动力。

Thermochromic compound[（C2 H5）2 NH2]2 CuCl4 displays a solid-solid phase transition at 52℃apparent with color changing from green to yellow,induced by the geometry of[CuCl4]2-anion（regarded as chromophore of the compound）ranging from square-planar to flattened tetrahedral structure.Fourier transform infrared（FTIR）spectroscopy and two-dimensional correlation（2D-COS）analysis have been applied to study the role played by the amine and ethyl group of the ammonium cation during the phase transition process in heating and cooling process.With temperature increasing,strength weakening of the N—H…Cl H-bond and thermal disordering of the alkyl chain both occur in the phase transition.2D-COS analysis reveals the N—H…Cl H-bond responds to increasing temperature in the first place and may the dominating driving force for the structure variation of[CuCl4]2-anion.