Rare configuration of tautomeric benzimidazolecarboxylate ligands in cadmium(II) and copper(II) coordination polymers
Journal
Journal of Solid State Chemistry
Journal Volume
184
Journal Issue
7
Pages
1740-1748
Date Issued
2011
Author(s)
Wu, J.-Y.
Yang, C.-W.
Chen, H.-F.
Jao, Y.-C.
Huang, S.-M.
Tsai, C.
Tseng, T.-W.
Lee, G.-H.
Lu, K.-L.
Abstract
Two Cd(HBimc)-based isomers, [Cd(HBimcN)(HBimc T)(H2O)]·3.5H2O·EtOH (1a·3.5H2O·EtOH, H2Bimc=1H-benzimidazole-5- carboxylic acid) and [Cd(HBimcN)(HBimcT)(H2O)] (1b), and two Cu(HMBimc)-based coordination polymers, [Cu(HMBimc N)2(H2O)]·1/2H2O (2·1/2H2O, H2MBimc=2-methyl-1H-benzimidazole-5- carboxylic acid) and [Cu(HMBimcT)2] ·2THF·H2O (3·2THF·H2O), were self-assembled from Cd(ClO4)2·6H 2O/H2Bimc and Cu(ClO4)2· 6H2O/H2MBimc systems, respectively. Compound 1a adopts a ladder-like chain structure, comprised of a hydrogen-bond-stabilized Cd 2(HBimcN)2-metallocyclic stair and a 1D straight (CdHBimcT)n edge, whereas compound 1b exhibits a 2D (4,4)-rhombus layered structure, intercrossed by 1D (CdHBimc N)n chains and (CdHBimcT)n chains. Compound 2 shows a 1D double-stranded wave-like chain from two single-stranded wave-like (CuHMBimcN)n chains and compound 3 adopts a 2D (4,4)-topological layer structure, intercrossed by subunits of 1D (CuHMBimc T)n chains. Interestingly, a pair of tautomeric HBimc building blocks - normal (N or HBimcN) and tautomer (T or HBimc T) - is simultaneously included in the structures of 1a and 1b, whilst the N- and T-configured HMBimc building blocks are present as separate entities in Cu species, 2 and 3, respectively. The existence of only a tautomer (T) mode of the benzimidazolecarboxylate-based ligand in a Cu(II) network is observed for the first time. © 2011 Elsevier Inc. All rights reserved.
Type
journal article