Solid-state thermochromism studied by variable-temperature diffuse reflectance spectroscopy. A new perspective on the chromism of salicylideneanilines
Solid-state thermochromism studied by variable-temperature diffuse reflectance spectroscopy. A new perspective on the chromism of salicylideneanilines
复制标题
DOI：
10.1021/jp037438g
复制
发表时间：
2004-04-01
影响因子：
3.3
通讯作者：
Ogawa, K
中科院分区：
文献类型：
--
作者：
Fujiwara, T;Harada, J;Ogawa, K
本文报道了变温漫反射光谱法在研究水杨醛缩苯胺类化合物固态热致变色和光致变色性方面的成功应用。这项研究反驳了已经被广泛接受长达40年的基本方面，并提供了一个新的视角。亚水杨基苯胺的烯醇形式被错误地认为是浅黄色，实际上是无色的，浅黄色是由于痕量的顺式酮形式，其与烯醇形式处于平衡状态。首次观察到顺式酮向反式酮的光转化。虽然人们已经接受，水杨叉基苯胺的给定的修改是光致变色或热致变色，但不是两者兼而有之，这项研究表明，这种排他性的性质上的变色不存在，水杨叉基苯胺通常是热致变色的固态，无论它们是光致变色或没有。这项研究表明，材料的颜色是由微量的有色物质控制的，变温漫反射光谱是一种非常有效的工具，用于检测，因此在固态的变色研究。
This paper reports a successful application of variable-temperature diffuse reflectance spectroscopy for the study of the solid-state thermo- and photochromism of salicylideneanilines, which belong to a class of the most well-known chromic organic compounds. This study disproves fundamental aspects that have been widely accepted for as long as 40 years and provides a new perspective on the chromism. The enol form of salicylideneaniline, which has been wrongly regarded as pale yellow, is in fact colorless, and the pale yellow is due to a trace of the cis-keto form, which is in equilibrium with the enol form. The phototransformation from the cis-keto to the trans-keto form was observed for the first time. Although it has been accepted that a given modification of salicylideneanilines is either photochromic or thermochromic but not both, this study reveals that such an exclusive property on the chromism does not exist and that salicylideneanilines are generally thermochromic in the solid state, whether they are photochromic or not. This study demonstrates that the color of materials is controlled by a trace of colored species and that the variable-temperature diffuse reflectance spectroscopy is quite an effective tool for its detection and therefore for the study of the chromism in the solid state.