Synthesis and crystal structure of (2.2.2-cryptand)potassium perchlorate

Abstract

A new complex (2.2.2-cryptand)potassium perchlorate [K(Crypt-222)]ClO4 is synthesized, and its structure is studied by X-ray diffraction analysis (space group R32, a = 8.441 A, c = 30.475 A, 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 = 0.032 for 1222 independent (with allowance for anomalous dispersion) reflections (CAD4 automated diffractometer, λMoKα radiation). The centers of the ClO4− anion and [K(Crypt-222)]+ complex cation are in the positions (0,0,0) and (0,0,1/2), respectively, with the point symmetry 32. The ClO4− anion is randomly disordered. The complex cation (with the high symmetry D3) is of the host-guest type and is somewhat disordered and exists as two different conformations with probabilities of 87 and 13%. The coordination polyhedron of the K+ cation (coordination number 8) is a two-base-centered trigonal prism distorted toward antiprism.