Syntheses, Characterizations, and Properties of Five Interpenetrating Complexes Based on 1,4-Benzenedicarboxylic Acid and a Series of Benzimidazole-Based Linkers

Five interesting interpenetrating networks, namely, [Co(p-bdc)(beb)0.5] n (1), {[Co(p-bdc)(bmb)]·H2O} n (2), {[Co(p-bdc)(bmp)]·H2O} n (3), {[Zn(p-bdc)(bmp)]·H2O} n (4), and [Zn2(p-bdc)2(bmp)(H2O)2] n (5) [p-H2bdc = 1,4-benzenedicarboxylic acid, beb = 1,4-bis(2-ethylbenzimidazol-1-ylmethyl)benzene, bmb = 1,4-bis(2-methylbenzimidazol-1-ylmethyl)benzene, and bmp = 1,5-bis(2-methylbenzimidazol) pentane], have been synthesized by employing mixed ligands of various benzimidazole-based ligands with p-H2bdc. Complex 1 possesses a 2-fold interpenetrating 3D framework with (412·63)-pcu topology. Complex 2 exhibits a 3-fold interpenetrating 3D network with 66-dia topology, and complex 3 displays a 4-fold interpenetrating 3D diamond network containing Co/bmp left- and right-handed helical chains. Obviously, with the reducing of the steric hindrance of the N-donor ligand, complexes 1–3 show interpenetrating networks from 2-fold to 3-fold and 4-fold. Complex 4 is isostructural to 3 and also forms a 4-connected 3D framework with a diamond topology. Complex 5 features a 3D framework generated by 2D → 3D interpenetration and exhibits (82·10)2 topology. Our study shows that the steric hindrance changing of ligands can tune the final interpenetrating networks directly.