A three-dimensional Zn^IIcoordination framework: poly[[μ₂-(E)-1,2-bis(pyridin-4-yl)ethene][μ₄-(E)-2,2′-(diazene-1,2-diyl)dibenzoato][μ₂-(E)-2,2′-(diazene-1,2-diyl)dibenzoato]dizinc(II)]

Abstract

In the title coordination polymer, [Zn2(C14H8N2O4)2(C12H10N2)]n, the asymmetric unit contains one Zn(II) cation, two halves of 2,2'-(diazene-1,2-diyl)dibenzoate anions (denoted L(2-)) and half of a 1,2-bis(pyridin-4-yl)ethene ligand (denoted bpe). The three ligands lie across crystallographic inversion centres. Each Zn(II) centre is four-coordinated by three O atoms of bridging carboxylate groups from three L(2-) ligands and by one N atom from a bpe ligand, forming a tetrahedral coordination geometry. Two Zn(II) atoms are bridged by two carboxylate groups of L(2-) ligands, generating a [Zn2(CO2)2] ring. Each loop serves as a fourfold node, which links its four equivalent nodes via the sharing of four L(2-) ligands to form a two-dimensional [Zn2L4]n net. These nets are separated by bpe ligands acting as spacers, producing a three-dimensional framework with a 4(6)6(4) topology. Powder X-ray diffraction and solid-state photoluminescence were also measured.