Synthesis and Crystal Structure of (18-Crown-6)(nitrato)(triphenylphosphine oxide)potassium

A new complex (18-crown-6)(nitrato)(triphenylphosphine oxide)potassium (I) is synthesized, and its crystal structure is studied by X-ray diffraction analysis (space group R3m, a = 14.336 Å, c = 13.776 Å, Z = 3). The structure is solved by the direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.034 for 1122 independent reflections (CAD4 automated diffractometer, λ MoK_α radiation). Structure I contains a complex host-guest molecule K(NO₃)(18-crown-6)(Ph₃PO)] with crystallographic symmetry 3m (three planes m contain three Ph rings of the Ph₃PO ligand and all O atoms of the crown ligand). The coordination polyhedron of the K⁺ cation is a distorted hexagonal bipyramid with all the six O atoms of the crown ligand in the base, the O atoms of the Ph₃PO ligand, and one (or two) O atoms of a disordered NO ₃ ^? ligand in the axial positions.