An azide-bridged copper(II) complex: poly[piperazine-1,4-dium [tetra-μ₃-azido-κ¹²N¹:N¹:N¹-hexa-μ₂-azido-κ¹²N¹:N¹-di-μ₂-azido-κ⁴N¹:N³-pentacopper(II)] tetrahydrate]

A new Cu(II)-azide complex, {(C4H12N2)[Cu5(N3)12]·4H2O}n, has been synthesized by the reaction of piperazine, Cu(OAc)2·2H2O (OAc is acetate) and NaN3. In the structure, μ2-1,1- and μ3-1,1,1-azide anions bridge five Cu(II) cations to form a linear pentanuclear cluster unit, which is further linked by μ2-1,1- and μ2-1,3-azide anions to form a two-dimensional condensed [Cu5(N3)12]n layer. The diprotonated piperazine and the solvent water molecules are hydrogen bonded to the coordination layers to form a three-dimensional supramolecular network.