Hybrid open frameworks (MIL-n).: Part 5 -: Synthesis and crystal structure of MIL-9:: a new three-dimensional ferrimagnetic cobalt(II) carboxylate with a two-dimensional array of edge-sharing Co octahedra with 12-membered rings

Co-5(OH)(2)(C4H4O4)(4), a new cobalt(II) succinate with an open framework, was prepared hydrothermally (180 degrees C, 72 h, autogenous pressure) from a 2:3 :8: 120 mixture of Co(II) chloride, succinic acid, potassium hydroxide and water. Its monoclinic structure was solved by single crystal X-ray diffraction [space group P2(1)/c (no. 14) with a = 9.5631(2) Angstrom, b = 9.4538(2) Angstrom; c = 12.5554(2) Angstrom, beta = 96.968(1)degrees, V = 1126.72(4) Angstrom(3), Z = 4] from 3077 unique reflections [I greater than or equal to 2 sigma(I)], R1 = 0.020 and wR2 = 0.054. The three-dimensional structure is built up from layers of edge sharing octahedra pillared by succinate ions. Within the layers, cobalt octahedra form 12-membered ring windows. Below 10 K, Co-5(OH)(2)(C4H4O4)(4), exhibits ferrimagnetic behavior.