Crystal structure of 1,10-diazonia-18-crown-6 diformate dihydrate

The crystal structure of 1,10-diazonia-18-crown-6 diformate dihydrate [H(2) DA18C6](2+) . 2HCO(2)(-) . 2H(2)O (I) was studied by X-ray diffraction: sp. gr. P2(1)/n; a = 9.920(1), b = 7.999(1), and c = 14.991(2) Angstrom; beta = 105.28(1)degrees; and Z = 2. Structure I was solved by the direct method and refined by the full-matrix least-squares procedure In the anisotropic ( isotropic for H atoms) approximation to R = 0.051 for all 2150 unique refle ctions measured (CAD-4 automated diffractometer, lambda CuKalpha). In struc ture I, the dication of DA18C6 is linked by hydrogen bonds with four adjace nt HCO2- anions, and its eighteen-membered macroheterocycle has a two-corne r conformation with the corners at the C(2) and C(2') atoms related by the symmetry center. No discrete molecular complexes of the guest-host type exi st in the crystal. Crystals of the molecular-ionic complex I consist of thr ee-dimensional layers formed by infinite along the y-axis chains of hydroge n-bonded DA18C6 dications, HCO2- anions, and the crystallization water mole cules, which are situated between these chains and linked to the HCO2- anio ns through hydrogen bonds.