Abstract

Two new metal-organic frameworks (MOFs) {[Cu₃(timb)₂(chtc)₂]·14H₂O}_n, (I) and {[Co₃(timb)₂(chtc)₂]·6H₂O}_n, (II) were hydrothermally synthesized by corresponding metal salt with mixed organic ligands of 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene (timb) and cyclohexane-1,3,5-tricarboxylic acid (H3chtc). Crystal structural analysis reveals that they exhibit varied structures. In the MOFs (I), Cu^II adopts an four coordination geometry, timb and cyclohexane-1,3,5-tricarboxylate ligands bridge neighboring Cu^II centers to result in two different one-dimensional knotted chains along the [0 − 1 2] and [1 0 − 1] directions, respectively. The two kinds of chains intersect each other vis Cu^II centers, resulting in a two-dimensional layered structure running parallel to the (1 2 1) plane. Adjacent layers are further linked by water moleculars via classical O–H…O hydrogen-bonding interactions, giving rise to a three-dimensional supramolecular network structure in the solid state. While in MOFs (II), the cyclohexane-1,3,5-tricarboxylate anions link the Co^II cations to generate a two-dimensional sheeted metal-organic structure running parallel to the bc plane. Adjacent sheets are further bridged by timb ligands, forming a porous three-dimensional metal-organic framework with a rare (3, 4)-connected (6.8²)₂(6².8⁴)₃(6².8)₂ topology. The solvent water molecules guest in the micropores of porous framework via water-carboxylate O–H…O hydrogen bonds. In addition, their thermal stabilities have also been investigated.

摘要

两种新型金属有机骨架（MOF）{[Cu ₃ (timb) ₂ (chtc) ₂ ]·14H ₂ O} _n , (I) 和{[Co ₃ (timb) ₂ (chtc) ₂ ]·6H ₂ O } _n , (II) 是由相应的金属盐与 1,3,5-三[(1H-咪唑-1-基)甲基]苯 (timb) 和环己烷-1,3,5-的混合有机配体水热合成的三羧酸（H3chtc）。晶体结构分析表明它们表现出不同的结构。在 MOFs (I) 中，Cu ^II采用四配位几何结构，timb 和环己烷-1,3,5-三羧酸盐配体桥接相邻的 Cu ^II中心以分别沿 [0 - 1 2] 和 [1 0 - 1] 方向产生两个不同的一维打结链。两种链在Cu ^{II中心处相互}交叉，形成平行于 (1 2 1) 平面的二维层状结构。相邻层通过经典的 O-H…O 氢键相互作用由水分子进一步连接，从而形成固态的三维超分子网络结构。而在 MOFs (II) 中，环己烷-1,3,5-三羧酸根阴离子连接 Co ^{II阳离子以产生与}bc平行的二维片状金属有机结构飞机。相邻片层进一步被 timb 配体桥接，形成具有稀有 (3, 4) 连接 (6.8 ² ) ₂ (6 ² .8 ⁴ ) ₃ (6 ² .8) ₂拓扑结构的多孔三维金属有机骨架. 溶剂水分子通过水-羧酸盐 O-H…O 氢键客体在多孔骨架的微孔中。此外，还研究了它们的热稳定性。