Three transition metal cluster-based coordination polymers based on 1,4-naphthalenedicarboxylate and pyridine ligands

Abstract

Three new cluster-based coordination polymers (CPs), namely, [Co2(1,4-NDC)2(py)2(H2O)] (1), [pyH]4[Ni6.5(1,4-NDC)8(OH)(py)4(H2O)3]∙H2O (2) and Zn4(1,4-NDC)3(OH)2(py)2 (3) (1,4-NDCH2=1,4-Naphthalenedicarboxylic acid, py=pyridine) have been hydrothermally synthesized and structurally characterized. Compound 1 is constructed from the tetranuclear clusters of [Co4(COOR)8(H2O)2]; while compound 2 contains trinuclear [Ni3(COOR)8(H2O)2]2− or tetranuclear [Ni4(COOR)8(OH)2]2− units owning to the disorder of metal ions. Both compounds feature three-dimensional (3D) structures with the eight-connected bcu networks. Compound 3 is the first 1,4-NDCH2-based 3D CP based on the rarely octanuclear [Zn8(μ3-OH)4(COOR)12] clusters with the six-connected pcu net. The three compounds are all constructed from the NDC2− and py ligands but their structures are quite different, revealing the significance of metal ions in the structural modulation of CPs. In addition, the thermal stabilities of the three compounds were investigated.