Christine Walbaum

Penta-, Hepta- und Oktaiodid-Anionen in Salzen mit Erdalkalimetall-Kronenether-Kationen / Penta-, Hepta-, and Octaiodide Anions in Salts with Alkaline Earth Metal Crown Ether Cations

Salts of alkaline earth metal cations sequestered in dibenzo-18-crown-6 (Db18c6) and benzo-15- crown-5 (B15c5), respectively, with I5−, I7− and I82− as the anions, have been synthesized and their crystal structures determined by single-crystal X-ray diffraction. [Ca(Db18c6)(H2O)3](I5)2- (Db18c6)(H2O) (1): monoclinic, P21 (no. 4), a = 1322.1(2), b = 1849.1(2), c = 1344.0(2) pm, β = 114.70(1)◦, V = 2985.2(6) × 106 pm3, Z = 2; [Sr(B15c5)2](I7)2 (2): triclinic, P1 (no. 2), a = 973.9(5), b = 1244.0(5), c = 1293.3(5) pm, α = 115.28(1), β = 90.18(1), γ = 104.57(1)◦, V = 1360.2(10) × 106 pm3, Z = 2; [Ba(Db18c6)2]I8 (3): orthorhombic, Pbcn (no. 60), a = 1452.0(2), b = 1924.6(2), c = 1912.1(2) pm, V = 5343.3(10) × 106 pm3, Z = 4. Compound 1 contains two crystallographically independent V-shaped pentaiodide anions, I5 −, which are linked to dimers by weak interionic contacts. The unusual heptaiodide anion, I7−, in 2 can be described as a V-shaped pentaiodide unit, which is connected to a slightly widened iodine molecule to give the rare Z form. Secondary bonding distances lead to almost planar ten-membered iodine rings, which are connected through common edges to form ribbons with staircase-like folding. 3 is built of sandwich-like cations and centrosymmetric octaiodide anions, I82−. An inspection for secondary contacts reveals that the iodine substructure of 3 consists of essentially isolated octaiodide units. Graphical Abstract Penta-, Hepta- und Oktaiodid-Anionen in Salzen mit Erdalkalimetall-Kronenether-Kationen / Penta-, Hepta-, and Octaiodide Anions in Salts with Alkaline Earth Metal Crown Ether Cations

Bis(benzo-15-crown-5-κ5O)strontium bis­(triiodide)

The title compound, [Sr(C14H20O5)2](I3)2, obtained by slow evaporation of an ethanol/dichloromethane solution (1:1) of SrCl2, benzo-15-crown-5 and I2, is built of sandwich-like [Sr(benzo-15-crown-5)2]2+ cations and isolated linear I3 − anions which are arranged in alternating layers parallel to (010). The triiodide anions are located in general positions, whereas the cations are located on centres of inversion.