Isomer dependent assembly of Ce(III) and Gd(III) coordination polymers containing 5-(n-pyridyl)tetrazole-2-acetato (n = 3,4)

Abstract

Isomer plays a vital role in the self assembly process of the coordination compounds. Tetrazole-carboxylate ligands with rich nitrogen and oxygen atoms are excellent candidates for the construction of novel coordination architectures. 5-(n-pyridyl)tetrazole-2-acetato potassium salt (denoted as Kn-pytza, n=3,4) was selected to be reacted with LnCl3·6H2O (Ln=Ce, Gd), resulting in the formation of [Ln(3-pytza)2Cl(H2O)2]n [Ln=Ce(1), Gd(2)] and [Ln(4-pytza)3(H2O)2]n·2nH2O [Ln=Ce(3), Gd(4)], respectively. The X-ray diffraction analysis reveals that compounds 1 and 2 are similar with one dimensional zigzag chains while compounds 3 and 4 are isomorphic with one dimensional ladder-like chains consisting of Ln2O6 (Ln=Ce, Gd) secondary building units (SBU) and the bridging 4-pytza, which can be attributed to the different coordination modes adopted by the isomeric ligands. In addition, the photoluminescence properties of the ligands and compounds 1–4 in the solid state were investigated at room temperature.