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

Abstract

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}_<i>n</i> (<b>1</b>) and {[Cd₄(tib)₄(H₂O)₄(NO₃)₆]·2NO₃}_<i>n</i> (<b>2</b>) (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 <b>1</b> and <b>2</b>. In <b>1</b>, 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 <b>2</b> possesses a 2-fold interpenetrating 2D framework with an extremely rare (3,4) connected topology. Photochemical properties of these new complexes have been studied