Preparation,crystal structure and thermal stability of porous lanthanide complexes with 5-methyl isophthalic acid

Three lanthanide complexes 1–3 with 5-methyl isophthalic acid (5-CH₃-H₂bdc) were prepared under hydrothermal conditions, two have formula Eu₂(5-CH₃-bdc)₃(EtOH) (2) and [Er(5-CH₃-bdc)_1.5] · (H₂O) (3) and were characterized by X-ray single crystal diffraction. In 2, there are two europium(III) ions in seven-coordinate pentagonal bipyramid and eight-coordinate bicapped trigonal prism geometries. Complex 2 is a 3-D porous structure with 1-D channels (potential solvent area = 453 ų, 15.7%). One crystallographic independent erbium(III) ion exists and lies in a pentagonal bipyramidal geometry in 3, in which one-dimensional channels are rectangular (potential solvent area = 470 ų, 16.4%). TG-DTG experiments show that these complexes have stability to 750–880°C decomposing to corresponding Ln₂O₃.