Synthesis and crystal structure of dibenzo-18-crown-6 oxonium perchlorate trihydrate

A hydrated crystalline ionized adduct of dibenzo-18-crown-6 and perchloric acid DB18C6 · H₃O⁺ · CiO ₄ ^? · 3H₂O (I) is synthesized and characterized by X-ray diffraction. The crystals of I are monoclinic: a = 17.760 Å, b = 12.922 Å, β = 124.27°, Z = 4, space group Cc. The structure of I is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.079 for 3294 independent reflections (CAD4 automated diffractometer, λMoK _α radiation). A DB18C6 molecule has a butterfly conformation with the rough symmetry C _2v . An H₃O⁺ · H₂O dimer is situated on one side of the DB18C6 macrocycle, and the ClO ₄ ^? anion and two other water molecules are on the other side. In the crystal of I, the DB18C6 molecules, H₃O⁺ and ClO ₄ ^? ions, and water molecules are linked through intermolecular (interionic) hydrogen bonds to form broad infinite chains running along the z axis.