Non-isomorphic chlorine-bromine substitution in the copper(I) halide π-complexes with 1-allyl-4-aminopyridinium

By alternating-current electrochemical synthesis crystals of {Cu[H2NC5H4N(C3H5)]Br-2}.H2O (I), {Cu[H2NC5H4N(C3H5)]Br0.65Cl1.35Cl1.35}.H2O (11) and {Cu[H2NC5H4N(C3H5)]Cl-2} (111) pi-complexes have been obtained and structurally investigated. The I and 11 compounds are isostructural and crystallize in a monoclinic sp. gr. P2(1)/c, 1: a = 7.359(2) Angstrom, b = 12.3880(6) Angstrom, c = 13.637(3) Angstrom, beta = 107.03(1)degrees, V = 1188.7(4) Angstrom(3), Z = 4 for C8H13N2OBr2Cu composition, R = 0.0293 for 2140 reflections. 11: a = 7.2771(6) Angstrom, b = 12.3338(3) Angstrom, c = 13.4366(7) Angstrom, beta = 107.632(2)degrees, V = 1149.3(l) Angstrom(3), Z = 4 for C8H13N2Br0.65Cl1.35Cu composition, R 0.0463 for 2185 reflections. Metal and halogen atoms form centrosymmetric Cu2X4 dimers. Each copper atom is surrounded by three halogen atoms and by a weakly bonded C = C-group of the onium moiety Isolated {Cu[H2NC5H4N(C3H5)]}(2)X-4 dimers are combined into a three-dimensional network due to a bridging function of water molecules via a system of rather strong hydrogen bonds. Chlorine derivative III crystallizes in another structure type: sp. gr. C2/c, a = 21.568(7) Angstrom, b = 7.260(2) Angstrom, c = 13.331(3) Angstrom, beta = 95.65(2)degrees, V = 2077(2) Angstrom(3), Z = 8 for C8H11N2Cl2Cu composition. Copper atom, included in CuCl2- isolated fragment, is coordinated to a C=C-bond of ligand moiety. N-H...Cl hydrogen bonds unite Cu[H2NC5H4N(C3H5)]Cl-2 subunits into infinite ribbons. pi-Interaction in III appears to be more effective than in I and II.