(Dibenzo-18-Crown-6)potassium Tetrachloroferrate(III): Synthesis and Crystal Structure

摘要

A new complex [K(Db18C6)]~+[FeCl4]~- (I) is synthesized and its structure is studied by X-ray diffraction analysis. The crystals are triclinic: space group P1,a= 17.998, b = 18.670, c = 19.590 A, α = 106.61°, β = 104.55°, γ=113.87°, Z = 8. The structure is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.057 by 13 670 independent reflections (CAD-4 automated diffractometer, λMoK_α). All the four independent complex cations [K(Db18C6)]~+ are host-guest, and in each complex cation the K~+ cation is localized in the cavity of the Db8C6 crown ligand. The coordination polyhedron of K~+ (coordination number nine) is a distorted hexagonal bipyramid with the base of all six O atoms of the Db18C6 ligand, the axial vertex at the Cl atom of the [FeCl4]~- anion, and another bifurcated axial vertex at two Cl atoms of another [FeCL4]~- anion. All the four independent [FeCL4]~- anions are orientationally disordered and have somewhat distorted tetrahedral structure. In crystal I, the alternating complex cations [K(Db18C6)]~+ and [FeCL4]~- anions form infinite polymer chains by the K-Cl bonds.