Syntheses, structures and magnetic properties of two isostructural metal-phosphonate frameworks

Two isostructural 2-dimensional (2D) layered metal phosphonates, [M5(Hptz)2(ptz)4]n (where M = Co(II) (1) and Mn(II) (2)) have been hydrothermally synthesized by using 4-(1,2,4-triazol-4-yl)phenylphosphonic acid (H2ptz) as a novel ligand. The magnetism studies over the temperature range 2-300 K showed pronounced antiferromagnetic interactions between the combined oxo- and diazo-bridged metal centers in both 1 and 2.