Construction of six coordination networks based on a flexible bis(methylbenzimidazole) ligand and isomeric benzenedicarboxylates

To explore the influence of isomeric benzenedicarboxylates on the self-assembly of coordination frameworks, six mixed-ligands Zn(II)/Co(II) coordination complexes, [Zn(pbmb)(1,4-bdc)]n (1), {[Co(pbmb)(1,4-bdc)]·1.5H2O}n (2), [M(pbmb)(1,3-bdc)]n [M = Zn (3) or Co (4)], and [M(pbmb)(1,2-bdc)]n [M = Zn (5) or Co (6)] (pbmb = 1,1′-(1,3-propane)bis-(2-methylbenzimidazole), 1,2-bdc = 1,2-benzenedicarboxylic acid, 1,3-bdc = 1,3-benzenedicarboxylic acid, and 1,4-bdc = 1,4-benzenedicarboxylic acid), have been obtained and structurally characterized. Structural analyses reveal that complexes 1 and 2 display 2D (4, 4) networks, of which complex 1 contains left- and right-handed helical chains arranged alternately and 2 owns a well-known paddle-wheel binuclear clusters. Complexes 3 and 4 feature 2D networks with 63 topologies, and complexes 5 and 6 exhibit 1D double-chain structures. Additionally, complexes 1–6 present high thermal stabilities, as well as 1, 3, and 5 show different photoluminescence behaviors in the solid state.