Synthesis and Crystal Structures of (2.2.2-Cryptand)rubidium Chloride and Bromide Hydrates

摘要

Two complexes, (2.2.2-cryptand)mbidium chloride and bromide hydrates [Rb(Crypt-222]Hal · 3.5H2O (Hal = Cl (I) and Br (II)), are synthesized. The structures of isomorphic crystals of compounds I and II are studied by X-ray diffraction analysis. The crystals are trigonal: space group P3, Z=2;I: a = 11.810 A, c = 11.302 A; II: a = 11.890 A, c = 11.402 A. The structures are solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.060 (I) and 0.077 (II) for 2650 (I) and 2700 (II) independent reflections (CAD-4 automated diffractometer, λMoK_α radiation). In crystals of complexes I and II, the [Rb(Crypt-222)]~+ cation of the host-guest type lies on the crystallographic axis 3 and has the approximate symmetry D3. In complexes I and II, the coordination polyhedron of the Rb~+ cation is a two-base-centered trigonal prism somewhat distorted to an antiprism. The crystals of compounds I and II contain H-bonded disordered cubes of the water molecules and Or or Br~- anions.