Synthesis and Properties of V₆O₁₆Cu(C₄H₄N₂)₂·(H₂O)_0.22(1):  Charge Density Matching of a Metal-Segregated Layer Structure

A metal-segregated layered compound, containing square nets of Cu(pyz)₂²⁺ and buckled V₆O₁₆^2- layers, has been synthesized using hydrothermal techniques to have the composition V₆O₁₆Cu(C₄H₄N₂)₂·(H₂O)_0.22(1) (C₄H₄N₂ = pyrazine, pyz). The Cu(II) square nets are nearly regular and undergo an antiferromagnetic transition at 8 K. In contrast to the plethora of recently synthesized metal−oxide clusters, chains, and networks in the VO_x/M/L (M = late transition element; L = organonitrogen ligand) system, this compound is a relatively rare example that contains two different metals distributed into distinct layers. An application of charge density matching to form layered structures is postulated.