The Crystal Structure of Bis(adiponitrilo)copper(I) Nitrate

Abstract The crystal structure of bis(adiponitrilo)-copper(I) nitrate has been determined by the two-dimensional Fourier method. It is orthorhombic Pnnn with two formula units in a cell of dimensions: a=9.41±0.02 Å, b=13.73±0.02Å and c=5.85±0.01 Å. The crystal consists of infinite three-dimensional networks of complex ion Cu(NC–CH2–CH2–CH2–CH2–CN)2nn+ and nitrate ions. A copper atom is tetrahedrally surrounded by four nitrogen atoms at a distance of 1.98 Å. Each adiponitrile molecule is coordinated to two different copper atoms with nitrogen atoms of both ends, forming a planar zigzag configuration of methylene groups. Thus the copper atoms and the ligand molecules form a complicated threedimensional 4-connected network. The nitrate ions lie perpendicularly to the a-axis. The trigonal nitrate ion seems to have statistical azimuthal orientations in the crystal and its apparent symmetry becomes 222. All the atoms in the group Cu–N–C–C lie approximately on a straight line. This fact and the observed carbon-nitrogen distance of 1.13 Å suggest that the bond character in the carbon-nitrogen group may essentially be expressed as C≡N. On the basis of the structures of this and the other related complexes, some remarks have been made on the mechanism of cuprous ion dyeing of polyacrylonitrile fibers.