摘要:
An ionized crystalline adduct of dibenzo-18-crown-6, perchloric acid, and water (H3O)[DB18K6](ClO4) is synthesized and structurally studied by X-ray diffraction. The crystals are triclinic: a = 8.582 angstrom, b = 10.486 angstrom, c = 26.293 degrees, alpha = 79.45 degrees, beta = 82.00 degrees, gamma = 79.36 degrees, Z = 4, space group ($) over bar1. The structure is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.098 for 5936 independent reflections (CAD4 automated diffractometer, lambda MoK (alpha) radiation). The structure contains two independent DB18C6 molecules, two independent H3O+ ions, and two independent ClO4- ions. The H3O+ ions each lie in the cavity of each of the two DB18C6 molecules and are retained there by three strong hydrogen bonds. Two DB18C6 molecules have close geometric parameters and a butterfly conformation with approximate symmetry C-2v. One of the two independent ClO4- anions is disordered over two orientations.