两种由萘二酰亚胺衍生物构建的配位聚合物的合成、结构和光致变色性能

Synthesis,structure,and photochromic properties of two coordination polymers built from 1,4,5,8-naphthalenediimide derivative

具有可逆颜色变化和适当变色寿命的光致变色材料对于无墨水和可擦除打印技术十分重要。我们将1,4,5,8-萘四羧酸二酐与甲硫氨酸结合,设计了一种基于1,4,5,8-萘二酰胺(NDI)的桥联有机配体(H2ncm),并以Zn^(2+)和H2ncm为原料,通过溶剂热反应合成了2种配位聚合物。化合物[Zn(ncm)(H_(2)O)_(4)]·2DMF(1)包含1个Zn^(2+)、1个ncm^(2-)配体、4个配位水分子和2个DMF分子。Zn^(2+)处于八面体的配位环境中,并通过ncm^(2-)配体连接形成链状结构。化合物[Zn_(2)(ncm)2(H_(2)O)_(4)](2)包含2个Zn^(2+)、2个ncm^(2-)配体和4个配位水分子。2个Zn^(2+)原子通过2个羧基桥联形成双核结构,并进一步通过ncm^(2-)配体连接形成二维层结构。2显示出从黄色到深棕色的光致变色现象。这种光诱导产生的颜色可以稳定至少3周,但在70℃加热时在5 min内即可恢复本来的颜色。我们证明了这种光致变色是源于光照射下NDI·自由基的产生。

Photochromic materials of reversible color change and appropriate photo-generated color lifetime are important for inkless and erasable printing technology.We designed a naphthalene diimide-based(NDI-based)ligand(H2ncm)by combining 1,4,5,8-naphthalenetetracarboxylic dianhydride with methionine and synthesized two coordination polymers from Zn^(2+)and H2ncm through solvothermal reactions.Compound[Zn(ncm)(H_(2)O)4]·2DMF(1)is composed of one Zn^(2+)ion,one ncm^(2-)ligand,four coordinated water,and two DMF solvent molecules.The Zn^(2+)ion is in an octahedral coordination environment and linked by ncm^(2-)ligands into a linear chain.Compound[Zn_(2)(ncm)2(H_(2)O)4](2)contains two Zn^(2+)ions,two ncm^(2-)ligands,and four coordinated water molecules.The two Zn^(2+)ions are bridged by two carboxylate groups into a binuclear Zn_(2)unit,which are linked by ncm^(2-)ligands into a layer structure.2 showed a photo-induced color change from yellow to dark brown.The photo-induced brown color could be stable for up to three weeks in the air but changed back to yellow within 5 min upon heating at 70℃.We showed that this photochromism originates from the generation of NDI·radical upon light irradiation.CCDC:2257324,1;2257325,2.