Crystal structure of triaqua(1,10-diaza-18-crown-6)chlorobarium chloride

The crystal structure of triaqua(1, 10-diaza-18-crown-6)chlorobarium chloride [Ba(DA18C6)Cl(H2O)(3)]Cl-+(-) (I) is studied by X-ray diffraction analysis: space group Pnma, a = 14.912, b = 13.590, c = 10.456 Angstrom, Z = 4. Structure I is solved by the direct method and refined by the full-matrix least-squares method in the anisotropic approximation: R = 0.079 for all 3194 measured independent reflections (CAD-4 diffractometer, lambda MoKalpha). Crystal I exists as complex guest-host cations and Cl- anions connected via interionic hydrogen bonds. The cations and anions are located in the in symmetry plane. The Ba2+ ion (coordination number 10) is in the cavity of the DA18C6 macrocycle acid is coordinated by its six heteroatoms (2N + 40) and also by the Cl- anion and two O atoms of two water molecules from one side of the macrocycle and by the O atom of the third water molecule from another side. The DA18C6 ligand in I has the conformation of a crown with an approximate D-3d symmetry.