Selenium-rich octanuclear iridium clusters with mixed-valent selenium ligands in the densest known packing of ellipsoids

Publikation: Beitrag in FachzeitschriftForschungsartikelBeigetragenBegutachtung

Beitragende

Abstract

Dark-red air-stable crystals of Ir8Se28Br 14·2H2O were obtained by reacting iridium in an excess of selenium and selenium tetrabromide at 300 °C for one week. The crystal structure is monoclinic (space group P21/n) with a = 1274.66(3) pm, b = 1211.48(3) pm, c = 1743.82(4) pm, and β = 91.227(1)° at 296(1) K. The structure consists of uncharged clusters Ir8Se 28Br14 = (Ir3+)8(Se2 2-)(Se42-)6(SeBr2) 2(Br-)10 with two water molecules attached to each of them. Selenium adopts three different oxidation states, -I in the diselenide dumbbell, -I and ±0 in the tetraselenide chains, and +II in the SeBr2 units. The iridium(III) cations are coordinated octahedrally by selenium atoms and bromide ions. The octahedra share common vertices, while the oligoselenide anions provide high intra-cluster connectivity: μ62 in the case of Se 22- and μ43 for Se 42-. In parts the cluster resembles a cut-out of the rhombohedral Ir3Se8 framework structure. The ellipsoidal clusters form an excellent approximation of the mathematically predicted densest known packing of ellipsoids, featuring the coordination number of 14.

Details

OriginalspracheEnglisch
Seiten (von - bis)719-723
Seitenumfang5
FachzeitschriftZeitschrift fur Anorganische und Allgemeine Chemie
Jahrgang640
Ausgabenummer5
PublikationsstatusVeröffentlicht - Apr. 2014
Peer-Review-StatusJa

Externe IDs

ORCID /0000-0002-2391-6025/work/159171941

Schlagworte

ASJC Scopus Sachgebiete

Schlagwörter

  • Clusters, Densest ellipsoid packing, Iridium, Mixed-valent compounds, Selenium