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