Synthesis, structure and properties of a new three-dimensional interpenetrated metal–organic framework with 3,3′-azodibenzoic acid (H₂azdc) and 1,4-bis(1H-imidazol-1-yl)butane (bimb): {[Cd(azdc)(bimb)₂]·H₂O}_n

Abstract

A new three-dimensional interpenetrated Cd(II)-organic framework based on 3,3'-azodibenzoic acid [3,3'-(diazenediyl)dibenzoic acid, H2azdc] and the auxiliary flexible ligand 1,4-bis(1H-imidazol-1-yl)butane (bimb), namely poly[[bis[μ2-1,4-bis(1H-imidazol-1-yl)butane-κ(2)N(3):N(3')][μ2-3,3'-(diazenediyl)dibenzoato-κ(2)O:O']cadmium(II)] monohydrate], {[Cd(C14H8N2O4)(C10H14N2)2]·H2O}n, (1), was obtained by a typical solution reaction in mixed solvents (water and N,N'-dimethylformamide). Each Cd(II) centre is six-coordinated by two O atoms of bis-monodentate bridging carboxylate groups from two azdc(2-) ligands and by four N atoms from four bimb ligands, forming an octahedral coordination environment. The Cd(II) ions are connected by the bimb ligands, resulting in two-dimensional (4,4) layers, which are further pillared by the azdc(2-) ligands, affording a threefold interpenetrated three-dimensional α-Po topological framework with the Schläfli symbol 4(12)6(3). The thermal stability and solid-state fluorescence properties of (1) have been investigated.