Hydrothermal synthesis of 3D porous architectures

A novel porous lanthanide-organic coordination polymer, [Nd(H2O)(HnicO)(TP)]·2H2O (1) (H2nicO=2-hydroxynicotinic acid, TP=terephthalate), was prepared under hydrothermal condition and characterized by single-crystal X-ray diffraction, thermogravimetric analysis and infrared spectroscopy. Compound 1 exhibited a flexible coordination geometry of lanthanide ions, which possessed a three-dimensional (3D) open framework with one-dimensional (1D) channels containing lattice water molecules. This framework structure exhibited a high stability up to 330 °C after removing free water molecules. A homometallic supramolecular framework (Zn(HnicO)2(H2O)2 (2)) was obtained due to the competitive reaction between organic ligands, Nd3+ and Zn2+ ions. The results showed that on the basis of the soft-hard/acid-base principle the coordination selection between metal ions and organic ligands played an essential role in the smart construction of lanthanide architectures.