The Crystal Structure of the Phenazine-Iodine Molecular Complex

Abstract The 1 : 1 molecular complex of phenazine and iodine crystallizes in an orthorhombic system with the space group Pbcn. There are four formula units in a unit cell with the dimensions of a=12.85, b=11.69, and c=8.30 Å. The structure was solved by Patterson methods and was refined by two-dimensional Fourier and (F0–Fc) syntheses. The component molecules are arranged alternately along the b axis, the two nitrogen atoms of the phenazine molecule and the two iodine atoms of the iodine molecule lying on a two-fold axis. The molecules of each component are stacked in individual columns parallel to the c axis, where the mean separations of the molecules satisfy the van der Waals distances. The phenazine molecule is planar within the range of experimental error. The interatomic distance of an iodine molecule is 2.75 Å; this is more from that of a free molecule, but not as large as those of the other iodine complexes. The charge-transfer interaction between phenazine and iodine is a little weakened by the steric hindrance of hydrogen atoms attached to the phenazine nucleus.