Syntheses and Structures of the First Examples of Lanthanide Complexes with 6‐Hydroxypicolinic Acid

Abstract

AbstractThree new complexes [La(HpicO)3(H2O)]n·0.5nH2O (1), [Eu(HpicO)3(H2O)3]n·3nH2O (2), and [Yb(HpicO)3(H2O)5]·4H2O (3) (H2picO = 6‐hydroxypicolinic acid) have been synthesized and characterized by single‐crystal x‐ray diffraction. Complexes 1 and 2 consist of 1D infinite chains, which are further assembled into 3D microporous coordination polymers by hydrogen bonds. Crystal water molecules stay in the channels. The complex 3 is of 3D supramolecular architecture self‐assembled via coordination bonds and hydrogen bonds. In these complexes, the carboxylate groups of HpicO— ligands act as tridentate, bidentate, and monodentate modes to coordinate to lanthanide ions. The thermogravimetric analyses of these complexes show that all coordinated and crystal water molecules are lost at the first weight loss. And final residues are lanthanide oxides.