Construction and photoluminescence properties of a three-dimensional ZnII coordination network based on naphthalene-1,4-dicarboxylic acid and 1,6-bis(pyridin-3-yl)-1,3,5-hexatriene.

Abstract

In recent years, coordination polymers constructed from multidentate carboxylate and pyridyl ligands have attracted much attention because these ligands can adopt a rich variety of coordination modes and thus lead to the formation of crystalline products with intriguing structures and interesting properties. A new coordination polymer, namely poly[[μ2-1,6-bis(pyridin-3-yl)-1,3,5-hexatriene-κ2N:N'](μ3-naphthalene-1,4-dicarboxylato-κ4O1,O1':O4:O4')zinc(II)], [Zn(C12H6O4)(C16H14N2)]n, has been prepared by the self-assembly of Zn(NO3)2·6H2O, naphthalene-1,4-dicarboxylic acid (1,4-H2ndc) and 1,6-bis(pyridin-3-yl)-1,3,5-hexatriene (3,3'-bphte) under hydrothermal conditions. The title compound has been structurally characterized by IR spectroscopy, elemental analysis, powder X-ray diffraction and single-crystal X-ray diffraction analysis. Each ZnII ion is six-coordinated by four O atoms from three 1,4-ndc2- ligands and by two N atoms from two 3,3'-bphte ligands, forming a distorted octahedral ZnO4N2 coordination geometry. Pairs of ZnII ions are linked by 1,4-ndc2- ligands, leading to the formation of a two-dimensional square lattice (sql) layer extending in the ab plane. In the crystal, adjacent layers are further connected by 3,3'-bphte bridges, generating a three-dimensional architecture. From a topological viewpoint, if each dinuclear zinc unit is considered as a 6-connected node and the 1,4-ndc2- and 3,3'-bphte ligands are regarded as linkers, the structure can be simplified as a unique three-dimensional 6-connected framework with the point symbol 446108. The thermal stability and solid-state photoluminescence properties have also been investigated.