Synthesis, crystal structure and properties of [CuII(H2O)6][CuII2(nta)2(pyz)]·4H2O: A channeled solid with three-dimensional hydrogen-bonding network

We report the synthesis and characterization of [CuII(H2O)6][CuII2(nta)2(pyz)]·4H2O. It consists of two molecular entities, a cation and an anion, containing divalent copper. These entities are held together by an extensive network of hydrogen-bonding to form a framework with channels (along the a-axis) housing molecules of water. The latter can be reversibly removed by evacuation at room temperature to give another crystal phase. The compound undergoes a fast solid-state reaction with KBr. Magnetic susceptibility data fit well to the sum of those of a dimer with a singlet-triplet gap of 9.21(5) K and a monomer.