Crystal structure of bis(4-dimethylaminopyridinium) tribromocuprate(I) and bis(4-dimethylaminopyridinium) tetrabromocuprate(II)

Abstract

The synthesis and crystal structures of two copper bromide salts of the 4-dimethylaminopyridinium (4DMAP+) cation are reported. The Cu(I) salt, (4DMAP)2CuBr3, crystallizes in the monoclinic space group C2/c, with a = 11.724(2), b = 11.055(3), c = 15.763(3) A, β = 107.64(3)°, and Z = 4. It contains isolated planar 4DMAP+ cations and trigonal planar CuBr32− anions. Small distortions from idealized D3h symmetry are observed for the anion. For the Cu(II) salt, (4DMAP)2CuBr4, a triclinic cell is observed with a = 8.2373(2), b = 9.2428(2), c = 14.4391(1) A, α = 93.760(1), β = 94.576(1), γ = 105.249(1)°, and Z = 2. This compound contains discrete planar 4DMAP+ cations and flattened tetrahedral CuBr42− anions. Small distortions are observed for ideal D2d symmetry.