The crystal structures of a macrocycle containing 2,6-pyridino and piperazino subunits and of the tetrachlorocobaltate(II) salt of its diprotonated cation
Abstract
The multiheteromacrocycle C26H38N6O4 is prepared by reaction of 2,6-dichloropyridine with NN′-bis-(2-hydroxyethyl)piperazine. Counter data obtained from crystals of space group P21/c having a= 10.498(3), b= 4.748(2), c= 26.032(8)Å, β= 96.42(2)°, and Z= 2 were used in the refinement, which converged with R 0.043 for 1 060 observed data. The molecule possesses crystallographic Ci symmetry with the piperazino subunits in the chair conformation. Reaction of this macrocycle with CoCl2 has led to diprotonation. Crystals of [C26H40N6O4][CoCl4] conform to space group P21/c with a= 15.258(6), b= 28.676(12), c= 15.538(5)Å, β= 107.18(3)°, and Z= 8. Refinement using 2 239 observed data measured on a diffractometer has yielded R 0.108. The crystal structure consists of [C26H40N6O4]2+ ions having essentially identical conformations to the macrocycle C26H38N6O4, each forming two hydrogen bonds to tetrahedral [CoCl4]2– ions. The Co–Cl distances within the complex anions average 2.260(8)Å. The array of [CoCl4]2– anions approximates a C-centred structure with the true b axis halved.