Design of lanthanide metal organic frameworks incorporating dicarboxylate ligands

Abstract

The combination under mild and solvo/hydrothermal condition of isophtalate (iso), oxalate (ox) and fumarate (fum) acid with lanthanide salts of La, Ce and Gd leads to the formation in crystalline state, of diverse dimensionality frameworks. The structures of four new metal organic frameworks, determined by single crystal X-ray diffraction, exhibit three different coordination patterns. [Gd2(iso)3(H2O)8]∙2(dmf)∙6H2O (1) (dmf = dimethylformamide) develops a 1D ribbons structure containing rectangular shaped channels filled with water and dmf solvents described by a 3-connected SP 1-periodic net (4,4)(0,2) topology. Compound {K[Gd2(iso)3(ox)(H2O)3]}∙(Hdma)∙H2O (2) ([Hdma]+ = [(CH3)2NH2]+) is an anionic 3D heterometallic framework constructed by mixed iso and ox ligands in diverse coordination modes leading to 1D open channels in which [Hdma]+ and water species are located. This network displays an unprecedented 2,3,14-c connected topology. 3D framework has been also observed for isotructural compounds [La2(fum)2(ox)(H2O)4]∙4H2O (3) and [Ce2(fum)2(ox)(H2O)4]∙4H2O (4) constructed by Ln–μ4–fumarate layers (Ln = La, Ce) interconnected by μ2–oxalate ligand forming intersected channels occupied by guest water molecules. These laters are also isostructural analogues of succinate series. The topological analysis of this network results in a binodal 4,5-c net with a 4,5T12 topology having Schlafli symbol of {44.62}{44.64.82}.