Synthesis, Structure, Luminescence, and Water Induced Reversible Crystal-to-Amorphous Transformation Properties of Lanthanide(III) Benzene-1,4-dioxylacetates with a Three-Dimensional Framework

Abstract

Three crystalline lanthanide(III) coordination polymers and their high quality single crystals with empirical formula [M2(BDOA)3(H2O)4]·6H2O [M = Tb (1), Gd (2), and Sm (3); BDOA = benzene-1,4-dioxylacetate] were obtained via the agar gel diffusion method. Their compositions and structures were determined and analyzed in detail by infrared spectroscopy, elemental analysis, and the single-crystal X-ray diffraction method. The ligand has two crystallographically independent coordination modes, La and Lb (L denotes BDOA); the metal centers are connected with La to form a double helix; these act as secondary building units (SBUs), which are linked by Lb resulting in a plane topology geometry with 54-membered macrorings; and each metal ion is saturated by water molecules to form a nine-coordinated sphere. These planes are further constructed into three-dimensional networks by a complicated H-bond system with an inversion center among the water molecules (coordinated and guest), the carboxylate group, and the p...