Uncharged Selenium Rings as Terminal and Bridging Ligands in Selenium‐Rich Iridium Clusters1. Issue 8 (2nd May 2014)

• Record Type: Journal Article
• Authors: Stolze, Karoline; Ruck, Michael
• Is Part Of: Zeitschrift für anorganische und allgemeine Chemie. Volume 640:Issue 8/9(2014)
• Page Start: 1559
• Page End: 1563
• Publication Date: 2014-05-02
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry -- Periodicals; 540
• DOI: 10.1002/zaac.201400092
• Languages: English
• ISSNs: 0044-2313

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Purple air‐stable crystals of Ir<sub>8</sub>Se<sub>40</sub>Br<sub>10</sub> were obtained by reacting Ir in an excess of Se and SeBr<sub>4</sub> at 300 °C for two weeks. The monoclinic crystal structure [space group <italic>P</italic>2<sub>1</sub>/<italic>c</italic>, <italic>a</italic> = 1371.9(1) pm, <italic>b</italic> = 1108.1(1) pm, <italic>c</italic> = 2058.2(1) pm, <italic>β</italic> = 106.897(2)° at 296(1) K] consists of uncharged clusters Ir<sub>8</sub>Se<sub>40</sub>Br<sub>10</sub> = (Ir<sup>3+</sup>)<sub>8</sub>(Se<sub>2</sub><sup>2–</sup>)(Se<sub>4</sub><sup>2–</sup>)<sub>6</sub>(Se<sub>7</sub>)<sub>2</sub>(Br<sup>–</sup>)<sub>10</sub>. The iridium(III) cations are coordinated octahedrally by selenium and bromide ions. While the oligoselenide anions provide high intra‐cluster connectivity, μ<sub>6</sub>‐η<sup>2</sup> in the case of Se<sub>2</sub><sup>2–</sup> and μ<sub>4</sub>‐η<sup>3</sup> for Se<sub>4</sub><sup>2–</sup>, the terminal uncharged Se<sub>7</sub> rings have boat conformation and are η<sup>1</sup>‐coordinating. About 10 % of the Se<sub>7</sub> rings are substituted by Se<sub>6</sub> rings with chair conformation. A similar reaction using SeCl<sub>4</sub> yielded vermillion air‐stable crystals of Ir<sub>2</sub>Se<sub>9</sub>Cl<sub>6</sub>. X‐ray diffraction on a single‐crystal revealed a tetragonal lattice (space group <italic>I</italic>4<sub>1</sub>/<italic>a</italic>) with <italic>a</italic> = 1229.8(1) pm and <italic>c</italic> = 2365.5(2) pm at 296(1) K. In the Se<sub>9</sub>(IrCl<sub>3</sub>)<sub>2</sub> cluster, a crown‐shaped uncharged Se<sub>9</sub> ring coordinates two iridium(III) cations as a bridging bis‐tridentate ligand. Three terminal chloride ions complete the distorted octahedral coordination of each transition metal atom.</p> </abstract>