Hydrothermal syntheses, structures and properties of five rare earth coordination polymers with (1,3,4-thiadiazole-2,5-diyldithio)diacetic acid

Hydrothermal reactions of rare earth ions(III) with a flexible building unit (1,3,4-thiadiazole-2,5-diyldithio)diacetic acid (H2tzda) lead to five novel coordination polymers with 1D chain and 3D network structures, namely, {[Y2(tzda)3(H2O)10] · 5H2O}n (1) and [Ln2(tzda)3(H2O)5]n [Ln = Er (2), Pr (3), Nd (4), Eu (5)]. Compound 1 has one-dimensional ribbon-like chain structure constructed by [Y2(tzda)3] units through the syn–anti bidentate bridging mode of carboxylate groups. Compounds 2–5 possess compact three-dimensional network structures which are made up of [Ln2(tzda)3] (Ln = Er, Pr, Nd and Eu) units bridged by carboxylate groups. In these compounds, the flexible tzda2− ligand is versatile and displays six different coordination fashions to meet the requirement of the coordination preference of the metal center. Furthermore, the magnetic behaviors for 2–5 in the temperature range of 5.0–300 K and photoluminescent property of 5 are significantly investigated in this paper.