Two new 1,2,4,5-cyclohexanetetracarboxylate-bridged frameworks with metal hydroxide subunits. Synthesis, structures, magnetism and adsorption.

The hydrothermal synthesis, X-ray crystal structures and thermal and magnetic properties of a layered coordination polymer, [Ni(3.9)Mn(1.1)(μ(3)-OH)(2)(L(I))(2)(H(2)O)(10)]·2H(2)O (1) (L(I) = 1e,2a,4a,5e-cyclohexanetetracarboxylate), and a porous 3D coordination polymer, [Ni(4)(μ(2)-OH)(2)(μ(6)-H(2)L(IV))(2)(pymc)(4,4'-bpy)(H(2)O)(2)](OH)·9H(2)O (2) (pymc = 2-pyrimidinecarboxylate, 4,4'-bpy = 4,4'-bipyridine, L(IV) = 1e,2e,4e,5e-cyclohexanetetracarboxylate), are reported in this paper. The structure of 1 has packed separated layers, each layer being formed of M(3)(μ(3)-OH)(2) chains bridged by M(L(I))(2)via hydrogen bonds. The magnetic properties are characterized by Néel transitions to fully compensated antiferromagnets at 2.9 K and show that 1 is a metamagnet resulting from the ferrimagnetic M(3)(μ(3)-OH)(2) chains and other two metal atoms. Complex 2 is a 3D microporous coordination framework with 2D channels. The conformation of the 1,2,4,5-cyclohexanetetracarboxylate ligands (H(4)L) of complex 2 changes from L(I) (e,a,a,e) to L(IV) (e,e,e,e). The magnetic measurement indicates spin-canted antiferromagnetic behaviour, and the adsorption measurements show that 2 can selectively adsorb CO(2) gas over N(2) gas.