Cadmium–Organic Coordination Polymers Based on N‑Donor Ligands and Small Anions: Syntheses, Crystal Structures, and Photoluminescent Properties

By using two types of arene core-based rigid N-containing ligands, we have solvothermally synthesized two cadmium metal–organic coordination polymers, {[Cd6(dpb)6(HCOO)8(H2O)4]·4NO3·4H2O}n (1) and {[Cd4(tib)4(H2O)4(NO3)6]·2NO3}n (2) (dpb = 1,4-bis-(4-pyridyl)-benzene, tib = 1,3,5-tris­(1-imidazolyl)­benzene), and characterized them. The coordinated small anions HCOO– and NO3– play important roles in the formation of 1 and 2. In 1, the coordinated formate ligand from in situ hydrolysis of DMF binds metal centers to generate a rigid 2D metal–formate honeycomb layer, which is further connected by dpb ligands to generate a 3D pillar–layer complex. Complex 2 possesses a 2-fold interpenetrating 2D framework with an extremely rare (3,4) connected topology. Photochemical properties of these new complexes have been studied.