Hydro-Ionothermal Synthesis of Lanthanide-Organic Frameworks with 1,4-Phenylenebis(methylene)diphosphonate

A synthetic approach combining hydrothermal and ionothermal (eutectic mixture of choline chloride and malonic acid) procedures is proposed that allowed the isolation of the first lanthanide-organic frameworks with residues of 1,4-phenylenebis(methylene)diphosphonic acid (H4pmd), [Ln(Hpmd)(H2O)] (where Ln3+ = Ce3+ and Pr3+), exhibiting an unprecedented trinodal topology with 3- and 8-connected nodes. The structural details were unveiled from single-crystal X-ray diffraction and the materials were characterized using standard techniques.