Copper(I) π-complexes with guanidine allyl derivatives: Synthesis and crystal structures of [CH2=CH-CH2-NHC(=NH2)2]CuCl 2-xBrx (x = 0.516) and [CH2=CH-CH2-NHC(=NH2)2]CuBr 2

Crystals of the [CH2=CH-CH2-NHC(=NH2)2]CuCl 2-xBrx (x = 0.516) (I) and [CH2=CH-CH2-NHC(=NH2)2]CuBr 2 (II) compounds were prepared by ac electrochemical synthesis, and their crystal structures were determined (a DARCh diffractometer, MoKα radiation, 1018 and 1453 independent reflections with F ≥ 4σ(F), R = 0.023 and 0.030 for I and II, respectively). The compounds are not isostructural. Parameters of I: space group Pna21 a = 15.741(6), b = 7.428(3), c = 7.387(3) Å, V = 864(1)Å3, Z = 4; parameters of II: space group P1, a = 8.142(3), b = 7.819(4), c = 7.067(2) Å, α = 84.39(4)°, β = 86.86(3)°, γ = 82.07(4)°, V = 443.1(6) Å3, Z = 2. In both structures, the allylguanidinium ligand is coordinated to copper through the C=C bond, whose length is equal to 1.343(7) Å in I and 1.343(9) Å in II. The structure of complex II is very similar to those of the known copper(I) π-complexes with S-allylisothiouronium [CH2=CH-CH2-SC(=NH2)2]CuX 2 (X = Cl- or Br-). © 1999 MAEe cyrillic signK "Hayκa/Interperiodica".