Bridging Nonaselenium Ring in [Se9(IrBr3)2], and Three Modifications of the Mononuclear Complex [IrBr3(SeBr2)3] |
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Authors: | Karoline Stolze Michael Ruck |
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Institution: | 1. Fachrichtung Chemie und Lebensmittelchemie, Technische Universit?t Dresden, 01062 Dresden, Germany;2. Max‐Planck‐Institut für Chemische Physik fester Stoffe, N?thnitzer Str. 40, 01187 Dresden, Germany |
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Abstract: | The reaction of iridium powder with an excess of selenium and SeBr4 yielded lustrous, vermillion crystals of the mononuclear iridium complex IrBr3(SeBr2)3]. The transition metal is coordinated octahedrally by three SeBr2 and three bromide ligands with facial or meridional configuration. Three different modifications were obtained under similar conditions: a‐fac‐IrBr3(SeBr2)3, space group P$\bar{1}$ , with a = 789.4(1) pm, b = 830.4(1) pm, c = 1334.4(1) pm, α = 81.634(5)°, β = 84.948(5)°, γ = 67.616(4)°; m‐fac‐IrBr3(SeBr2)3, space group P21/n, with a = 1205.3(1) pm, b = 962.4(1) pm, c = 1383.9(1) pm, β = 91.114(3)°; mer‐IrBr3(SeBr2)3, space group P21/n with a = 859.7(1) pm, b = 1284.3(1) pm, c = 1437.5(1) pm, β = 94.427(3)°. A lower bromine content in the starting composition resulted in shiny, deep‐red crystals of Se9(IrBr3)2]. X‐ray diffraction on a single‐crystal revealed a tetragonal lattice (space group I41/a) with a = 1245.4(1) pm and c = 2486.8(1) pm at 296(1) K. In the Se9(IrBr3)2] complex, a crown‐shaped uncharged Se9 ring coordinates two iridium(III) cations as a bridging bis‐tridentate ligand. Three terminal bromide ions complete the distorted octahedral coordination of each transition metal atom. |
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Keywords: | Coordination compounds Iridium Polymorphism Selenium dibromide Selenium molecules |
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