Synthesis and crystal structure of (18-crown-6)(perchlorato-O)(triphenylphosphine oxide)potassium

A new complex, (18-crown-6)(perchlorato-O)(triphenylphosphine oxide)potassium, was synthesized and its structure was studied by X-ray diffraction. The crystals are trigonal: a = 14.419,c = 13.895 Å, Z = 3, space group R3m; the structure was solved by the direct method and refined by the anisotropic full-matrix least-squares method, R = 0.079 on 1930 independent reflections, CAD-4 automated diffractometer, λMoK _α . The structure contains a highly symmetric host-guest complex molecule [K(ClO₄)(18-crown-6)(Ph₃PO)] in position 3m (with three Ph rings of the Ph₃PO ligand and all the O atoms of a crown ligand lying in three m planes). The coordination polyhedron of the K⁺ cation is a distorted hexagonal bipyramid with six O atom of the 18-crown-6 ligand in a base and the O atom of the Ph₃PO ligand and disordered O atom of the ClO ₄ ^? ligand in the axial vertices.