The crystal structures of the cryptates Ag(C222)X, X=ClO4-, NO3-, ClO3-, BrO3-, IO4-, ReO4-, BF4-, PF6-, AsF6-, and Na(C222)X, X=ClO4-, IO4-, ReO4-

Single crystal structure determinations of the complexes of 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo-[8.8.8]hexacosane, C18H36N2O6 (=C222), with AgClO4 (1) [R32, a=8.589(2)Angstrom, c=27.553(11)Angstrom, T=92K] and NaIO4 (2) [Peen, a=10.402(5)Angstrom, b=13.452(9)Angstrom, c=17.172(9)Angstrom, T=293K] were performed. The cell constants of the cryptates Ag(C222)X (X=NO3-, C1O(3)(-), BrO3-, ClO4-, IO4-, ReO4-, BF4-, PF6-, AsF6-) and of Na(C222)ClO4 were determined from powder diffraction data, and are all isotypic to (1). Indexing of the powder spectrum of Na(C222)ReO4 resulted in an orthorhombic unit cell comparable to that of (2), but with a c-axis reduced by one half. In these compounds the metal cations lying at the centres of the ligand cavities are clearly separated from the anions [>5.4 Angstrom]. In both the AgClO4 and NaIO4 complexes the metal cations have coordination numbers of 8, but the coordination types are quite different: Whereas the Ag+ ion prefers N to O coordination [2xAg...N 2.372(3)Angstrom, 6xAg...O 2.834(3)Angstrom], at the Na+ ion the situation is inverted [2xNa...N 2.710(5)Angstrom, 6xNa...O 2.403(4)Angstrom-2.529(4) Angstrom]. The metal-ligand distances and the conformational changes of the C222 ligand are discussed taking as a basis the data of all known crystal structures containing this ligand.