Copper(I) π-complexes with allyl derivatives of guanidine:: Synthesis and crystal structure of the [(CH2=CH-CH2-NH=)3C]Cu3Cl4-xBrx (x=1.23) and [(CH2=CH-CH2-NH=)3C]Cu3Br4 compounds

Crystal compounds [(CH2=CH-CH2-NH-)(3)C]Cu3Cl4-xBrx (x = 1.23) (I) and [(CH2=CH-CH2-NH-)(3)C]Cu3Br4 (II) were prepared by ac electrochemical synthesis and structurally characterized [DARCh diffractometer, MoKalpha radiation, 1258 (I) and 1488 (II) reflections with F greater than or equal to 4 sigma(F), R = 0.031 and 0.037 for I and II, respectively]. The crystals of the isostructural compounds are trigonal, space group R3, Z = 3. Unit cell parameters are a = 10.332(3), c = 13.990(3) Angstrom, V = 1294(1) Angstrom(3) for I and a = 10.542(3), c = 14,326(3) Angstrom, V = 1379(1) Angstrom(3) for II. The trigonal-pyramidal coordination sphere of the copper atom involves three halogen atoms and a C=C bond in the equatorial plane. The inorganic Cu3X4- anions are positioned in axes 3 and combined with triallylguanidinium cations into layers by the Cu-(C=C) interactions. The length of the coordinated C=C bond is 1.35(1) Angstrom in I and 1.34(1) Angstrom in II. Net atomic charges are calculated for structure I.