A Variety of 1D to 3D Metal−Organic Coordination Architectures Assembled with 1,1′-(2,2′-Oxybis(ethane-2,1-diyl))bis(1<i>H</i>-imidazole)

A new long flexible ligand, L = 1,1′-(2,2′-oxybis(ethane-2,1-diyl))bis(1H-imidazole), has been prepared. The hydrothermal reactions of L with various metal ions (M(II) = Co, Zn, and Cd) as well as a series of aromatic polycarboxylate co-ligands yielded seven new metal−organic frameworks consisting of 1D, 2D, and 3D structures. Complexes 1–5 are constructed by SBU I (a M2L2 metallocycle), while complexes 6 and 7 are assembled by SBU II (left- and right-handed helical [M(L)]n chains). In 1and 2, the SBUs I are bridged by 1,2-BDC (1,2-benzenedicarboxylate) and 3,5-DNP (3,5-dinitrophthalate) anions with the same coordination modes to generate 1D chains with repeated rings. 3 exhibits a typically 3-fold interpenetrated 3-connected (10,3)-b net. In 4, the Co centers are connected by μ3-OH and carboxylic O atoms to form a cobalt−oxygen tetranuclear cluster. 5 represents an uncommon example of a 3,4-connected net with (83)2(85 × 10) topology. In 6, the SBUs II are extended by 1,4-BDC (1,4-benzenedicarboxylate) anions to afford highly undulated 2D (4, 4) layers. In 7, the [Cd3(1,3-BDC)3] ladders connect to SBUs II to form a corrugated 2D network. A comparison of all complexes demonstrates that the structural characteristics of L ligand and organic counteranions simultaneously play an important role in the construction of the complexes. In addition, complexes 3 and 7 exhibit strong blue photoluminescence, and compound 4 is an antiferromagnet.本研究合成了一种新型长柔性配体L，其化学结构为1,1′-(2,2′-氧二(乙烷-2,1-二基))双(1H-咪唑)。将配体L与多种金属离子（M(II)包括Co、Zn、Cd）以及一系列芳香族多羧酸辅助配体进行水热反应，成功制备得到7种具有一维、二维和三维结构的新型金属有机框架材料。配合物1~5由次级构筑单元（Secondary Building Unit, SBU）I（一种M₂L₂金属环）构筑而成，而配合物6和7则由次级构筑单元II（左手与右手螺旋状[M(L)]ₙ链）组装得到。在配合物1和2中，次级构筑单元I通过配位模式一致的1,2-苯二甲酸根（1,2-BDC）与3,5-二硝基邻苯二甲酸根（3,5-DNP）桥连，形成带有重复环结构的一维链。配合物3呈现典型的三重穿插3连接(10,3)-b拓扑网络。在配合物4中，Co中心通过μ3-羟基与羧酸氧原子连接，形成四核钴氧簇。配合物5是一种罕见的3,4-连接拓扑网络，其拓扑类型为(8³)₂(8⁵×10)。在配合物6中，次级构筑单元II通过1,4-苯二甲酸根（1,4-BDC）阴离子拓展为高度褶皱的二维(4,4)层状结构。在配合物7中，[Cd₃(1,3-BDC)₃]梯状结构与次级构筑单元II连接，形成波纹状二维网络。对所有配合物的对比分析表明，配体L与有机抗衡阴离子的结构特征在配合物的构筑过程中同时发挥着关键作用。此外，配合物3和7展现出强烈的蓝色光致发光性能，而配合物4则具有反铁磁特性。