Hydrothermal syntheses, crystal structures, and thermal stability of two new 3D open-framework metal(II) phosphonates

This article reports the hydrothermal synthesis and characterization of two new phosphonate compounds NaCo[O3PCH(OH)CO2] (1) and NaMn[O3PCH(OH)CO2] (2) based on 2-hydroxyphosphonoacetic acid (H3L). Their structures have been characterized by single-crystal X-ray diffraction as well as with elemental analysis, infrared spectroscopy and thermogravimetric analysis. The two isomorphous compounds crystalline in the orthorhombic, space group Pbca: Crystal data for 1: a = 10.1827(8) Å, b = 9.6673(8) Å, c = 10.7853(9) Å, V = 1061.70(15) Å3, Z = 8, R 1 = 0.0252, wR 2 = 0.0577; Crystal data for 2: a = 10.4309(18) Å, b = 9.7913(17) Å, c = 10.9012(19) Å, V = 1113.4(3) Å3, Z = 8, R 1 = 0.0194, wR 2 = 0.0536. In the two compounds, the metal atoms are octahedrally coordinated; all oxygen atoms from the H3L ligand are involved in coordination. The overall structures can be described as a 3D open framework with channels running along the a axis and the charge-compensating Na+ cations being located at the intersections of these channels.