Synthesis,crystal structure and magnetic properties of a two‐dimensional cyanide‐based heterometallic coordination polymer with cationic piperazinium ligands: poly[aquatetra‐μ2‐cyanido‐κ8C:N‐dicyanido‐κ2C‐(piperazinium‐κN4)cobalt(III)copper(II)]

Cyanide as a bridge can be used to construct homo‐ and heterometallic complexes with intriguing structures and interesting magnetic properties. These ligands can generate diverse structures, including clusters, one‐dimensional chains, two‐dimensional layers and three‐dimensional frameworks. The title cyanide‐bridged Cu^II–Co^III heterometallic compound, Cu^IICo^III(CN)₆(C₄H₁₁N₂)(H₂O)]_n, has been synthesized and characterized by single‐crystal X‐ray diffraction analysis, magnetic measurement, thermal study, vibrational spectroscopy (FT–IR) and scanning electron microscopy/energy‐dispersive X‐ray spectroscopy (SEM–EDS). The crystal structure analysis revealed that it has a two‐dimensional grid‐like structure built up of Cu(Hpip)(H₂O)]³⁺ cations (Hpip is piperazinium) and Co(CN)₆]^3? anions that are linked through bridging cyanide ligands. The overall three‐dimensional supramolecular network is expanded by a combination of interlayer O—H...N and N—H...O hydrogen bonds involving the coordinated water molecules and the N atoms of the nonbridging cyanide groups and monodentate cationic piperazinium ligands. A magnetic investigation shows that antiferromagnetic interactions exist in the title compound.