Structural research on mixed thiocyanate copper(II) complexes with multidentate ligands containing nitrogen as the donor atom. Crystal and molecular structures of isothiocyanato[NN′-bis(2-pyridylmethy-lene) tetramethylenediamine]copper(II) thiocyanate and of bis(isothio-cyanato)[ 2-(2-pyridyl)benzimidazolel]copper(II)

Abstract

The structures of the title compounds have been determined from X-ray diffraction data by the heavy-atom method and refined by least squares. Crystal data: [Cu(C₁₆H₁₈N₄)NCS]SCN, (I), a= 13.93(1), b= 9.78(1), c= 15.06(1)Å. β= 96.8(1)°, Z= 4, space group P2₁/c, final R 6.7%; [Cu(C₁₂H₉N₃)(NCS)₂], (II), a= 14.96(1), b= 12.23(1), c= 8.57(1)Å, β= 106.8(1)°. Z= 4, space group P2_I/n, final R 4.3%. In (I) the copper co-ordin-ation is trigonal bipyramidal and involves five nitrogen atoms, one from a thiocyanate group (Cu–N 1.99 Å) and the four nitrogen atoms of the organic ligand (Cu–N 2.03,1.99,2.00, and 2.19 Å).One thiocyanate group is ionic and has no direct interaction with the metal. In (II) the co-ordination polyhedron is a nearly regular tetragonal pyramid formed by two nitrogen atoms from the organic ligand (Cu–N 2.05 and 1.97 Å) and two from two thio-cvanate oroups (Cu–N 1.95 and 1.94 Å) in the basal plane with a sulphur atom from one thiocyanate group (Cu–S 2.95 Å) at the apex.