Liu Jian Jun, Liu Teng, Huang Chang Cang
Center for Yunnan-Guizhou Plateau Chemical Functional Materials and Pollution Control, Qujing Normal University, Qujing 655011, People's Republic of China.
College of Chemistry, Fuzhou University, Fuzhou 350108, People's Republic of China.
Acta Crystallogr C Struct Chem. 2017 Jun 1;73(Pt 6):437-441. doi: 10.1107/S2053229617006544. Epub 2017 May 9.
Naphthalene diimides, which are planar, chemically robust and redox-active, are an attractive class of electron-deficient dyes, which can undergo a single reversible one-electron reduction to form stable radical anions in the presence of electron donors upon irradiation. This makes them excellent candidates for organic linkers in the construction of photochromic coordination polymers. Such a photochromic one-dimensional linear coordination polymer has been prepared using N,N'-bis(3-carboxyphenyl)naphthalene-1,8:4,5-tetracarboximide (HBBNDI). Crystallization of HBBNDI with magnesium nitrate in an N,N'-dimethylformamide (DMF)/ethanol/HO mixed-solvent system under solvothermal conditions afforded the one-dimensional coordination polymer catena-poly[[bis(dimethylformamide-κO)magnesium(II)]-bis[μ-N-(3-carboxylatophenyl)-N'-(3-carboxylphenyl)naphthalene-1,8:4,5-tetracarboximide-κO:O']], [Mg(CHNO)(CHNO)]. The asymmetric unit contains half of a magnesium cation, one HBBNDI ligand and one DMF molecule. Two partially deprotonated HBBNDI ligands bridge two magnesium cations to form a one-dimensional chain. Strong inter-chain π-π interactions between the naphthalene rings of the HBBNDI ligand and the imide rings of adjacent chains provide a two-dimensional structure. The supramolecular three-dimensional framework is stabilized by π-π interactions between naphthalene rings of neighbouring two-dimensional supramolecular networks. The complex exhibits a reversible photochromic behaviour, which may originate from the photoinduced electron-transfer generation of radicals in the HBBNDI ligand.
萘二亚胺具有平面结构、化学稳定性高且具有氧化还原活性，是一类极具吸引力的缺电子染料，在光照下，在电子供体存在的情况下，它可以进行单一的可逆单电子还原反应，形成稳定的自由基阴离子。这使其成为构建光致变色配位聚合物的有机连接体的理想候选物。使用N,N'-双(3-羧基苯基)萘-1,8:4,5-四羧酸二亚胺(HBBNDI)制备了这种光致变色的一维线性配位聚合物。在溶剂热条件下，HBBNDI与硝酸镁在N,N'-二甲基甲酰胺(DMF)/乙醇/H₂O混合溶剂体系中结晶，得到一维配位聚合物链状聚[[双(二甲基甲酰胺-κO)镁(II)]-双[μ-N-(3-羧基苯基)-N'-(3-羧基苯基)萘-1,8:4,5-四羧酸二亚胺-κO:O']]，[Mg(CH₃NO)(CH₃NO)]。不对称单元包含半个镁阳离子、一个HBBNDI配体和一个DMF分子。两个部分去质子化的HBBNDI配体桥连两个镁阳离子形成一维链。HBBNDI配体的萘环与相邻链的酰亚胺环之间强烈的链间π-π相互作用提供了二维结构。相邻二维超分子网络的萘环之间的π-π相互作用稳定了超分子三维框架。该配合物表现出可逆的光致变色行为，这可能源于HBBNDI配体中自由基的光诱导电子转移生成。
