Construction of metal–organic coordination networks with various metal-linker secondary building units: structures and properties†
Abstract
One homometallic and two heterometallic coordination networks, namely [Zn2(2,6-PDC)2] (1), [CaPb6(2,6-PDC)6]Cl2 (2) and [Mg1.5Ce(2,6-PDC)3(H2O)3]·3.5H2O (3), have been synthesized via a hydrothermal method, where 2,6-PDC is 2,6-pyridinedicarboxylate. Crystal structure analysis reveals that complexes 1–3 are all made up of metal-linker secondary building units (SBUs) and metal nodes. Complex 1 features an sql net structure, which can be regarded as the combination of two different (4,4) topological 2D networks. One 2D network is composed of flattened tetrahedral [Zn(2,6-PDC)2]2− metal-linker SBUs and penta-coordinated Zn-shared nodes and the other 2D network consists of 2-connected 2,6-PDC ligands and 4-connected Zn(II) nodes. Compared with the 2D structure of 1, 2 and 3 possess 3D framework structures. Complex 2 is composed of 18-connected octahedral [Ca(2,6-PDC)6]10− metal-linker SBUs and 3-connected Pb(II) nodes, displaying a 3,18-connected gez net. Complex 3 has a well-known topological type of 4,6-connected stp net and 1D hexagonal nanochannels, which is composed of 6-connected triangular prismatic [Ce(2,6-PDC)3]3− metal-linker SBUs and 4-connected Mg(II) nodes. Moreover, the luminescence and iodine adsorption properties of complexes are also investigated.