METAL-ION COMPLEXES OF WATER-SOLUBLE CALIX[4]ARENES

Three transition metal complexes of water-soluble calixarenes have been prepared and structurally characterized, demonstrating the three possible modes of incorporation of metals into the solid-state layered structure. [Cr(OH2)6][Na][calix[4]arenesulfonate](acetone).10.5H2O (1), in which the Cr(OH2)6(3+) species is intercalated within the hydrophilic layer and an acetone molecule sits within the calixarene cavity, crystallizes in the monoclinic space group P2(1)/n with a = 12.206 (6) angstrom, b = 31.251 (4) angstrom, c = 13.420 (6) angstrom, beta = 96.63 (3)-degrees, and D(c) = 1.54 g cm-3 for Z = 4. Refinement based on 3518 observed reflections converged at a conventional R of 0.070. [Yb(OH2)7][Na][calix[4]arenesulfonate].9H2O (2), in which a Yb(OH2)7(3+) moiety binds directly to a sulfonate oxygen, crystallizes in the triclinic space group P1BAR with a = 12.362 (3) angstrom, b = 13.656 (3) angstrom, b = 13.964 (3) angstrom, alpha = 88.99 (2)-degrees, beta = 74.89 (2)-degrees, gamma = 90.59 (2)-degrees, and D(c) = 1.80 g cm-3 for Z = 2. Refinement based on 4210 observed reflections converged at R = 0.057. {[Cu(OH2)4][Na]2[calix[4]arenesulfonate].7.5H2O}2 (3), in which Cu(OH2)4(2+) units interact with sulfonate oxygens of different calixarene molecules in both an intralayer and an interlayer fashion, crystallizes in the monoclinic space group P2(1) with a = 11.955 (3) angstrom, b = 28.499 (6) angstrom, c = 12.442 (3) angstrom, beta = 91.49 (2)-degrees, and D(c) = 1.66 g cm-3 for Z = 4. Refinement based on 3910 observed reflections converged at a conventional R of 0.054. In the parent Na4[calix[4]arenesulfonate].13.5H2O, the thickness of the hydrophilic layer is 8.41 angstrom. The corresponding thickness in 1 is 9.98 angstrom compared to 7.51 angstrom for 2. Surprisingly, the layer-spanning copper complex in 3 reduces this distance only slightly to 8.02 angstrom.