Multidimensional Networks Constructed with Isomeric Benzenedicarboxylates and 2,2‘-Biimidazole Based on Mono-, Bi-, and Trinuclear Units

Three new complexes of [Co(H2biim)2(1,2-bdc)] (1), [Cd(H2biim)(1,3-bdc)]2 (2), and [Cd3(H2biim)2(1,4-bdc)3]·2H2O (3) (bdc = benzenedicarboxylate, H2biim = 2,2‘-biimidazole) have been synthesized and characterized
by single-crystal X-ray diffraction. Complex 1 exhibits a 2-D herringbone architecture with mononuclear building
blocks assembled via a robust hydrogen-bonded synthon R22(9). The homo- and heterochiral assemblies were observed
in 1 between the H2biim ligand and carboxylate group via single and double hydrogen-bonded synthons R22(9).
Complex 2 is a ribbonlike polymer based on a binuclear unit, and the ribbons are alternately decorated by H2biim
ligands on both sides and further packed through intercalation of the lateral H2biim ligands and hydrogen bonds
between the H2biim and carboxylate oxygen atoms into 2-D networks. These layers extend into a 3-D architecture
via π−π stacking interactions. Complex 3 is a 3-D coordination polymer with a α-Po net topology based on linear
trinuclear {Cd3O14N4} clusters. The results indicate that isomeric benzenedicarboxylates give structural diversity
in the presence of auxiliary ligand H2biim, providing a potential tool for crystal engineering.