Synthesis, Structure, and Magnetism of a Highly Thermally Stable Microporous Metal Organodiphosphonate with Reversible Dehydration/Rehydration Behavior

The synthesis and crystal structure of a novel organic–inorganic hybrid material Co 2 (H 2 O) 2 [O 3 PCH 2 (C 6 H 4 )CH 2 PO 3 ] is described. It crystallizes in the orthorhombic space group Pca 2(1) [ a = 9.6214(19), b = 5.6855(11), c = 21.725(4) Å, V = 1188.4(4) Å 3 ], which consists of two‐dimensional cobalt–oxygen inorganic layers pillared by p ‐xylylenediphosphonateto form a three‐dimensional framework, which has 10.850 × 5.687 Å channels running along the b ‐axis. The material is exceptionally stable, even when heated up to 500 °C in air. More interestingly, the framework components display a reversible dehydration/rehydration behavior. There is an antiferromagnetic interaction between the cobalt ions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)