A Highly Stable 3D Porous Lanthanum Metal-organic Framework Constructed From A New Flexible Bis(benzoic acid) Ligand Produced in Situ

By employing diethyl 1,3-propylidenebis(4-oxybenzoate) as a precursor, the new three-dimensional metal-organic framework [La2L2(HL)(2)] n [L = 1,3-propylidenebis(4-oxybenzoate)] was prepared and characterized by single-crystal X-ray diffraction analysis, elemental analysis, infrared spectroscopy, and thermogravimetric analysis. The compound crystallizes in the triclinic space group P (1) over bar, with cell parameters: a = 8.299 (2) angstrom, b = 14.127 (3) angstrom, c = 14.520 (3) angstrom, a = 112.43 (3)degrees, beta = 103.10 (3)degrees, gamma = 95.28 (3)degrees, V = 1502.2 (5) angstrom(3), and Z = 1. Under hydrothermal reaction conditions, two ester groups of the ligand hydrolyzed into carboxylate groups. The carboxylate groups coordinated in situ to metal ions to form the 3D coordination polymer. It exhibits a 10.4 x 10.6 angstrom rhombic channel along the [011] direction. On the basis of the results of TG analysis, the structure is thermally stable up to approximate to 400 degrees C.