Copper(I) pi-complexes with guanidine allyl derivatives: Synthesis and crystal structures of [CH2=CH-CH2-NHC(=NH2)(2)]CuCl2-xBrx (x= 0.516) and [CH2=CH-CH2-NHC(=NH1)(2)]CuBr2

Crystals of the [CH2=CH-CH2-NHC(=NH2)(2)] CuCl2-xBrx (x = 0.516) (I) and [C H2=CH-CH2-NHC(= NH2)(2)]CuBr2 (II) compounds were prepared by ac electroche mical synthesis, and their crystal structures were determined (a DARCh diff ractometer, MoKalpha radiation, 1018 and 1453 independent reflections with F greater than or equal to 4 sigma(F), R = 0.023 and 0.030 for I and II, re spectively). The compounds are not isostructural. Parameters of I: space gr oup Pna2(1), a = 15.741(6), b = 7.428(3), c = 7.387(3) Angstrom, V = 864(1) Angstrom(3), Z = 4; parameters of II: space group P (1) over bar, a = 8.14 2(3), b = 7.819(4), c = 7.067(2) Angstrom, alpha = 84.39(4)degrees, beta = 86.86(3)degrees, gamma = 82.07(4)degrees, V = 443.1(6) Angstrom(3), Z = 2. In both structures, the allylguanidinium ligand is coordinated to copper th rough the C=C bond, whose length is equal to 1.343(7) Angstrom in I and 1.3 43(9) Angstrom in II. The structure of complex II is very similar to those of the known copper(I) pi-complexes with S-allylisothiouronium [CH2=CH-CH2S C(=NH2)(2)] CuX2 (X = Cl- or Br-).