(C5H12N)Cu2Br3: A Piperidinium Copper(I) Bromide with [Cu2Br3]− Ladders

Piperidinium copper(I) bromide, (C5H12N)Cu2Br3, was obtained from a solution of CuBr2, piperidine, and HBr in ethanol. At 60 °C ethanol slowly reduces copper(II) to copper(I). Colorless plates of (C5H12N)Cu2Br3 crystallize in the triclinic space group P-1 with lattice parameters of a = 6.2948(10) A, b = 8.2624(14) A, c = 10.7612(17) A, α = 75.964(19)°, β = 89.232(19)°, γ = 84.072(19)°, and Z = 2 at 173 K. [CuBr4] tetrahedra share edges and form [Cu2Br3]− ladders parallel to the a-axis. (C5H12N)+ ions adopt a chair conformation and connect the [Cu2Br3]− ladders via H-bonding. The (C5H12N)Cu2Br3 structure is related to the mineral rasvumite, KFe2S3, space group Cmcm, which is isostructural to several alkali copper(I) halides.