Fine tuning of the Cd(II)-bis(benzimidazole) networks by changing carboxylate anions.

Three new polymeric frameworks, [Cd(bbbi)(ita)(H2O)] · H2O (1), [Cd(bbbi)(fma)] (2), and [Cd(bbbi)(fma)(H2O)] · 2H2O (3) (bbbi = 1,1-(1,4-butanediyl)bis-1 H-benzimidazole, H2ita = itaconic acid, and H2fma = fumaric acid), have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Complex 1 is a 2-D (4,4) network containing infinite 1-D zigzag Cd(II)-bbbi chains linked by auxiliary ita ligands. In the structure of 2, infinite 1-D linear Cd(II)-bbbi chains are linked by fma ligands to generate an undulated 2-D (4,4) network. In 3, an in situ ligand transformation occurred with malate converted to H2fma by dehydration. Thus, a 2-D (4,4) grid network constructed from bbbi and fma was obtained. The carboxylates with different substituents play an important role in the formation of the final frameworks and coordination modes of Cd(II). Thermal stability and luminescent properties of 1-3 were investigated. [ABSTRACT FROM AUTHOR]