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Uncharged Selenium Rings as Terminal and Bridging Ligands in Selenium‐Rich Iridium Clusters
Author(s) -
Stolze Karoline,
Ruck Michael
Publication year - 2014
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201400092
Subject(s) - iridium , monoclinic crystal system , chemistry , crystallography , selenium , crystal structure , octahedron , bromide , tetragonal crystal system , ligand (biochemistry) , cyclohexane conformation , cluster (spacecraft) , stereochemistry , molecule , inorganic chemistry , hydrogen bond , catalysis , organic chemistry , biochemistry , receptor , computer science , programming language
Purple air‐stable crystals of Ir 8 Se 40 Br 10 were obtained by reacting Ir in an excess of Se and SeBr 4 at 300 °C for two weeks. The monoclinic crystal structure [space group P 2 1 / c , a = 1371.9(1) pm, b = 1108.1(1) pm, c = 2058.2(1) pm, β = 106.897(2)° at 296(1) K] consists of uncharged clusters Ir 8 Se 40 Br 10 = (Ir 3+ ) 8 (Se 2 2– )(Se 4 2– ) 6 (Se 7 ) 2 (Br – ) 10 . The iridium(III) cations are coordinated octahedrally by selenium and bromide ions. While the oligoselenide anions provide high intra‐cluster connectivity, μ 6 ‐η 2 in the case of Se 2 2– and μ 4 ‐η 3 for Se 4 2– , the terminal uncharged Se 7 rings have boat conformation and are η 1 ‐coordinating. About 10 % of the Se 7 rings are substituted by Se 6 rings with chair conformation. A similar reaction using SeCl 4 yielded vermillion air‐stable crystals of Ir 2 Se 9 Cl 6 . X‐ray diffraction on a single‐crystal revealed a tetragonal lattice (space group I 4 1 / a ) with a = 1229.8(1) pm and c = 2365.5(2) pm at 296(1) K. In the Se 9 (IrCl 3 ) 2 cluster, a crown‐shaped uncharged Se 9 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.