Crystal structure of 1,10-diazonia-18-crown-6 (+)-tartrate tetrahydrate

The crystal structure of 1,10-diazonia-18-crown-6 (+)-tartrate tetrahydrate [H(2)DA18C(6)](2+) . C4H4O62- . 4H(2)O (I) has been determined by X-ray di ffraction analysis. The unit cell parameters are as follows: a = 7.634(2), b = 8.677(2), and c = 11.034(3) Angstrom; alpha = 70.88(2)degrees, beta = 7 0.11(2)degrees, and gamma = 65.40(2)degrees; space group P1; and Z = I. The structure of compound I is solved by the direct method and refined by the full-matrix least-squares procedure in the anisotropic (isotropic for the h ydrogen atoms) approximation to R = 0.055 for all 1676 measured reflections (CAD4 automated diffractometer, lambda CuKalpha). The molecular-ionic comp lex I in the crystal state exhibits a complex (three-dimensionally infinite ) supramolecular structure formed by sufficiently strong hydrogen bonds and electrostatic attraction of the counterions. In structure I, the (+)-tartr ate dianion has an approximate twofold axis, and the DA18C6 dication adopts a conformation with the approximate symmetry D-3d. crystal I, water molecu les are linked together by hydrogen bonds into the chains infinite along th e y-axis. The main feature of the crystal structure understudy is the prese nce of infinite (along the x-axis) sandwich-like stacks composed of the DA1 8C6 dications alternating with the (+)-tartrate dianions.