Three-Dimensional Cd(II) Coordination Polymers Based on Semirigid Bis(Methylbenzimidazole) and Aromatic Polycarboxylates: Syntheses, Topological Structures and Photoluminescent Properties

To systematically explore the influence of aromatic polycarboxylate coligands on building high-dimensional Cd(II)-bmb (1,4-bis(2-methylbenzimidazol-1-ylmethyl) benzene) coordination polymers, we synthesized six coordination polymers, namely {[Cd(bmb)(o-phda)]·H2O}n (1), [Cd(bmb)0.5(m-phda)]n (2), [Cd(bmb)(p-phda)]n (3), [Cd(bmb)0.5(oba)]n (4), [Cd(bmb)(bpdc)]n (5), [Cd2(bmb)(bta)(mta)0.5]n (6), (H2phda = phenylenediacetic acid, H2oba =4,4′-oxybis(benzoic acid), H2bpdc = biphenyl-4,4′-dicarboxylic acid, H3bta =1,2,4-benzenetricarboxylic acid, and H2mta = 2-(methoxycabonyl)terephthalic acid) by varying aromatic polycarboxylate coligands. Structural analyses reveal that polymers 1–6 display diverse 3D frameworks and topologies, in which all of the N-donor ligands bmb exhibit trans-conformation but with different Ndonor···N–Csp3···Csp3 torsion angles. Polymer 1 shows a 3-fold interpenetrating dia array with a 4-connected 66 topology. Polymer 2 features a (3,4)-connected pillar-layered structure with (63)(65·8...