Synthesis, Crystal Structure and Magnetic Properties of a Coordination Polymer [Ni(cpna)(bpy)(H2O)]n

A coordination polymer, namely [Ni(cpna)(bpy)(H2O)](n) (1) has been constructed hydrothermally using H(2)cpna (H(2)cpna=5-(2'-carboxylphenyl) nicotic acid), bpy (bpy=2,2'-bipyridine) and Ni(OAc)(2)center dot 4H(2)O. The complex crystallizes in the monoclinic system, space group P2(1)/c with a=1.666(2) nm, b=0.962 2(12) nm, c=1.270 2(16) nm, beta=105.978(12)degrees, V=1.957(4) nm(3), D-c=1.608g center dot cm(-3), Z=4, R=0.038 7 and wR=0.089 3 (1 > 2 sigma(1)). Three Ni(II) atoms, three cpna ligands, three 2,2'-bpy ligands, and three water ligands form a [Ni-3(cpna)(3)(bpy)(3)(H2O)(3)] ring. The rings are connected by the coordination interactions of cpna ligands and Ni(II) ions to generate a 2D sheet, which are further extended into a 3D metal-organic supramolecular framework by pi-pi stacking interactions. Magnetic studies for complex 1 show a weak antiferromagnetic coupling between the nearest Ni(II) centers, with g=2.10 and J=-0.87 cm(-1). CCDC: 816351.