Su Feng, Yu Jinyang, Zhou Chengyong, Li Shaodong, Ma Pengyi, Zhang Xuhui, Wang Zhijun
Department of Chemistry, Changzhi University, Changzhi 046011, People's Republic of China.
College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, People's Republic of China.
Acta Crystallogr C Struct Chem. 2020 Jun 1;76(Pt 6):547-556. doi: 10.1107/S205322962000604X. Epub 2020 May 13.
Two new Zn-based metal-organic frameworks (MOFs) based on biphenyl-2,2',5,5'-tetracarboxylic acid, i.e. H(o,m-bpta), and N-donor ligands, namely, poly[[(μ-biphenyl-2,2',5,5'-tetracarboxylato)bis{[1,3-phenylenebis(methylene)]bis(1H-imidazole)}dizinc(II)] dimethylformamide monosolvate dihydrate], {[Zn(CHO)(CHN)]·CHNO·2HO} or {[Zn(o,m-bpta)(1,3-bimb)]·CHNO·2HO} (1) {1,3-bimb = [1,3-phenylenebis(methylene)]bis(1H-imidazole)}, and poly[[(μ-biphenyl-2,2',5,5'-tetracarboxylato)bis{[1,4-phenylenebis(methylene)]bis(1H-imidazole)}dizinc(II)] monohydrate], {[Zn(CHO)(CHN)]·HO} or {[Zn(o,m-bpta)(1,4-bimb)]·HO} (2) {1,4-bimb = [1,4-phenylenebis(methylene)]bis(1H-imidazole)}, have been synthesized under solvothermal conditions. The complexes were characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction and powder X-ray diffraction analysis. Structurally, the (o,m-bpta) ligands are fully deprotonated and combine with Zn ions in μ-coordination modes. Complex 1 is a (3,4)-connected porous network with honeycomb-like [Zn(o,m-bpta)] sheets formed by 4-connected (o,m-bpta) ligands. Complex 2 exhibits a (2,4)-connected network formed by 4-connected (o,m-bpta) ligands linking Zn ions in left-handed helical chains. The cis-configured 1,3-bimb and 1,4-bimb ligands bridge Zn ions to form multi-membered [Zn(bimb)] loops. Optically, the complexes show strong fluorescence and display larger red shifts compared to free H(o,m-bpta). Complex 2 shows ferroelectric properties due to crystallizing in the C polar point group.
基于联苯 - 2,2',5,5'-四羧酸（即H(o,m-bpta)）和含氮供体配体，即聚[[(μ - 联苯 - 2,2',5,5'-四羧基)双{[1,3 - 亚苯基双(亚甲基)]双(1H - 咪唑)}二锌(II)]二甲基甲酰胺单溶剂合物二水合物]，{[Zn(CHO)(CHN)]·CHNO·2HO} 或 {[Zn(o,m-bpta)(1,3 - bimb)]·CHNO·2HO} (1) {1,3 - bimb = [1,3 - 亚苯基双(亚甲基)]双(1H - 咪唑)}，以及聚[[(μ - 联苯 - 2,2',5,5'-四羧基)双{[1,4 - 亚苯基双(亚甲基)]双(1H - 咪唑)}二锌(II)]一水合物]，{[Zn(CHO)(CHN)]·HO} 或 {[Zn(o,m-bpta)(1,4 - bimb)]·HO} (2) {1,4 - bimb = [1,4 - 亚苯基双(亚甲基)]双(1H - 咪唑)}的两种新型锌基金属有机框架（MOF）已在溶剂热条件下合成。通过红外光谱、元素分析、单晶X射线衍射和粉末X射线衍射分析对这些配合物进行了表征。在结构上，(o,m-bpta)配体完全去质子化并以μ - 配位模式与锌离子结合。配合物1是一个(3,4) - 连接的多孔网络，具有由4 - 连接的(o,m-bpta)配体形成的蜂窝状[Zn(o,m-bpta)]片层。配合物2呈现出一个(2,4) - 连接的网络，由4 - 连接的(o,m-bpta)配体在左手螺旋链中连接锌离子形成。顺式构型的1,3 - bimb和1,4 - bimb配体桥连锌离子形成多员[Zn(bimb)]环。在光学性质上，这些配合物显示出强荧光，并且与游离的H(o,m-bpta)相比呈现出更大的红移。配合物2由于结晶于C极性点群而表现出铁电性质。
