Piperazinium,Ethylenediammonium or 4,4′‐Bipyridinium Halocuprates(I) by CuII/Cu0 Comproportionation

1‐Dimensional halocuprate(I) chains [(Cu₂X₄)^2–]_n (= [(CuX₂)^–]_n, X = Cl, Br, I) have been synthesized under hydrothermal conditions through in‐situ reduction of Cu^IIX₂ with Fe^IIX₂ or as phase pure materials through comproportionation of Cu^IIX₂ or Cu^IIO with Cu⁰ metal in the presence of the respective aqueous hydrogen halide HX and a templating amine. Chains of trans edge‐sharing tetrahedra are obtained with piperazinium or ethylenediammonium dications, while the 4,4′‐bipyridinium dication gave chains of cis edge‐sharing tetrahedra. Two monoprotonated piperazinium groups act as cationic ligands (Hpipz⁺) towards copper atoms in a molecular [Cu₄(μ‐Br₆)(Hpipz)₂] cluster. Electrical crystal conductivities of the halocuprate [(Cu₂X₄)^2–]_n (= [(CuX₂)^–]_n) chains (X = Cl, Br, I) are around 10^–8 S · cm^–1 at room temperature.