Crystal structures of thiocyanate polyamine copper(II) complexes. Part VI. Di-(3-aminopropyl)aminebis(isothiocyanato)copper(II)

Abstract

The crystal structure of the title compound has been determined by three-dimensional X-ray data. Crystals are monoclinic, space group P2₁/a, with Z= 4 in a unit cell of dimensions: a= 7·58(2), b= 14·12(2), c= 13·58(2)Å, β= 113·2(3)°. The structure was solved by Patterson and Fourier methods and refined by least-squares techniques to R 0·033 for 1689 refined reflections measured by diffractometer. The co-ordination polyhedron is a tetragonal pyramid with the basal plane occupied by the amine [Cu–N(prim) 2·02, Cu–N(sec) 2·06] and thiocyanate nitrogen (Cu–N 2·04) atoms; the apical position is filled by the nitrogen atom of the second thiocyanate group (Cu–N 2·14 Å). The mutually trans Cu–N(sec) and Cu–N(NCS) bonds evidence an antisymbiotic trans-effect with hard metal and ligands. The bonding of the thiocyanate group in other polyamine copper complexes is discussed in terms of Pearson's concept of hard and soft acids and bases (HSAB).