Three Lanthanide-Carboxylate Coordination Polymers with Conformation Variation Based on Flexible Ligands: Syntheses, Structures and Photoluminescence Properties

Reactions of flexible dicarboxylate ligands 2,2-(1,4-phenylenebis (methylene))bis(sulfanediyl)dibenzoic acid (H2L1) and 2,2-(2,3,5,6-tetramethyl-1,4-phenylene)bis (methylene)bis (sulfanediyl) dibenzoic acid (H2L2) with lanthanide metal salts under solvothermal conditions give rise to three lanthanide-organic coordination polymers (CPs), namely, {[(NH2 (CH3)(2)] [Nd (L-1)(2) (DMF)] center dot 2DMF}(n) (1) and {[Ln (L-2)(1.5) (H2O)(DMF)(2)] center dot 2DMF}(n) [Ln = Ce (2), Pr (3)] (DMF=N,N-dimethylformamide). All of the complexes have been structurally characterized by single-crystal X-ray diffraction analyses and characterized by elemental analysis, infrared spectra (IR), powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). All the complexes have two-dimensional (2D) layer structures, which can be simplified as (4,4) net. The ligands display different conformation. (L-1)(2-) in complex 1 exhibits two kinds of conformations: syn- and anti-conformation, while (L-2)(2-) in complexes 2 and 3 exhibits anti-conformation. Furthermore, the thermal stabilities and photoluminescence properties of the complexes were investigated. CCDC: 1482586, 1; 1482588, 2; 1482587, 3.