Su Chang Kai, Zhang Kou Lin
School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu 225002, People's Republic of China.
Acta Crystallogr C Struct Chem. 2018 Apr 1;74(Pt 4):504-512. doi: 10.1107/S2053229618004382. Epub 2018 Mar 26.
Two new Co coordination polymers (CPs), namely, catena-poly[[[(5-amino-2,4,6-tribromobenzene-1,3-dicarboxylato-κO)aquacobalt(II)]-bis[μ-1,3-bis(imidazol-1-ylmethyl)benzene-κN:N']] 4.75-hydrate], {[Co(CHBrNO)(CHN)(HO)]·4.75HO}, (1), and poly[(μ-5-amino-2,4,6-tribromobenzene-1,3-dicarboxylato-κO:O)[μ-1,2-bis(imidazol-1-ylmethyl)benzene-κN:N']cobalt(II)], [Co(CHBrNO)(CHN)], (2), have been synthesized successfully by the assembly of multifunctional 5-amino-2,4,6-tribromoisophthalic acid (HATBIP) and Co ions in the presence of the flexible isomeric bis(imidazole) ligands 1,3-bis(imidazol-1-ylmethyl)benzene (mbix) and 1,2-bis(imidazol-1-ylmethyl)benzene (obix). The isomeric mbix and obix ligands have a big influence on the structures of CPs (1) and (2). CP (1) is composed of chains of nanometre-sized elliptical rings, in which the Co atom exhibits a distorted octahedral coordination geometry and ATBIP acts as a monodentate ligand. Two adjacent chains are interlinked by π-π stacking interactions and hydrogen bonds, resulting in a supramolecular double chain. Hydrogen-bonded R(16) rings extend adjacent supramolecular double chains into a two-dimensional supramolecular layer. Halogen bonding and a hydrogen-bonded R(8) ring further link the two-dimensional supramolecular layers, leading to the formation of a three-dimensional supramolecular network. The Co ion in CP (2) is tetracoordinated, exhibiting a distorted tetrahedral configuration. The ATBIP ligand exhibits a bis(monodentate) coordination bridging mode, linking adjacent Co ions into zigzag chains, which are further bridged by the auxiliary bridging obix ligand, resulting in a two-dimensional (4,4) topological network. Interlayer hydrogen and halogen-halogen bonding further extend the two-dimensional layers into a three-dimensional supramolecular network. A detailed analysis of the solid-state UV-Vis-NIR diffuse-reflectance spectra of (1) and (2) indicates that a wide optical band gap exists in both (1) and (2). CP (1) exhibits an irreversible dehydration-rehydration behaviour.
成功合成了两种新型钴配位聚合物（CPs），即链状聚[[[(5-氨基-2,4,6-三溴苯-1,3-二羧酸根-κO)水合钴(II)]-双[μ-1,3-双(咪唑-1-基甲基)苯-κN:N']] 4.75水合物]，{[Co(CHBrNO)(CHN)(HO)]·4.75HO}，(1)，以及聚[(μ-5-氨基-2,4,6-三溴苯-1,3-二羧酸根-κO:O)[μ-1,2-双(咪唑-1-基甲基)苯-κN:N']钴(II)]，[Co(CHBrNO)(CHN)]，(2)，它们是通过在柔性异构体双(咪唑)配体1,3-双(咪唑-1-基甲基)苯（mbix）和1,2-双(咪唑-1-基甲基)苯（obix）存在下，多功能5-氨基-2,4,6-三溴间苯二甲酸（HATBIP）与钴离子组装而成。异构体mbix和obix配体对CPs（1）和（2）的结构有很大影响。CP（1）由纳米尺寸的椭圆形环链组成，其中Co原子呈现扭曲的八面体配位几何构型，ATBIP作为单齿配体。两条相邻链通过π-π堆积相互作用和氢键相互连接，形成超分子双链。氢键连接的R(16)环将相邻的超分子双链扩展成二维超分子层。卤键和氢键连接的R(8)环进一步连接二维超分子层，导致形成三维超分子网络。CP（2）中的Co离子是四配位的，呈现扭曲的四面体构型。ATBIP配体呈现双(单齿)配位桥连模式，将相邻的Co离子连接成锯齿链，这些链进一步由辅助桥连配体obix桥连，形成二维(4,4)拓扑网络。层间氢键和卤-卤键进一步将二维层扩展成三维超分子网络。对（1）和（2）的固态紫外-可见-近红外漫反射光谱的详细分析表明，（1）和（2）中都存在较宽的光学带隙。CP（1）表现出不可逆的脱水-再水合行为。
