Novel double layer salts of copper(I) bromide with N-substituted ethylenediammonium cations

The structures of three hybrid organic/inorganic halometalate salts are reported, and the layer structures developed are contrasted. Crystal structures of the isostructural N-methylethylenediammonium (MEDA(2+)) and N-ethylethylenediammonium (EEDA(2+)) salts of copper(I) bromide are both triclinic, space group P1, with lattice constants a = 6.284(7), b = 7.842(6), and c = 12.03(1) A, alpha = 84.84(3), beta = 83.08(2), and gamma = 88.00(3) degrees, and V = 586(1) A(3) with Z = 2 for (MEDA)Cu(2)Br(4) while (EEDA)Cu(2)Br(4) has lattice constants a = 6.27(2), b = 7.78(2), and c = 13.12(3) A, alpha = 84.69(4), beta = 78.18(3), and gamma = 88.17(7) degrees, and V = 623(3) A(3) with Z = 2. The dominant inorganic feature in both salts is anionic (CuBr(2))(n)(n-) chains of edge-shared CuBr(4) tetrahedra. The diammonium cations hydrogen bond these chains together into a unique double layer structure. For comparison purposes, the crystal structure of (CHA)PbBr(3) (CHA(+) = cyclohexylammonium) is reported (monoclinic, space group P2(1)/n, a = 8.088(2) A, b = 7.912(2) A, and c = 19.572(4) A, beta = 96.98(4) degrees, and V = 1243.2(4) A(3) with Z = 4). This contains (PbBr(3))(n)(n-) halometalate chains, this time of face-shared PbBr(6) octahedra. However, here the organic cations tie the chains together into the more common single layer structure.