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Reaktionen und Strukturen von [(C 2 H 5 ) 4 N][OsCl 6 ] und [(n-C 4 H 9 ) 4 N] 2 [Os 2 Cl 10 ] / Reactions and Structures of [(C 2 H 5 ) 4 N][OsCl 6 ] and [(n-C 4 H 9 ) 4 N] 2 [Os 2 Cl 10 ]

1984; De Gruyter; Volume: 39; Issue: 7 Linguagem: Inglês

10.1515/znb-1984-0701

1865-7117

Bernt Krebs, Gerald Henkel, M. DARTMANN, W. Preetz, Michael Bruns,

Crystallography and molecular interactions

On heating of [(C 2 H 5 ) 4 N][OsCl 6 ] for a short time at 240 °C , Cl 2 is lost and [(C 2 H 5 ) 4 N] 2 [Os 2 Cl 10 ] is formed quantitatively. Both complexes are connected by a temperature dependent redox equilibrium so that by treatment at 120 °C with Cl 2 gas the hexachloroosmate(V) is recovered from the decachlorodiosmate(IV). The crystal structures of salts of both an ions were determined from single crystal X -ray diffraction analyses. [(C 2 H 5 ) 4 N][OsCl 6 ] is monoclinic, space group P2 1 with a = 7 .020 (1), b = 10 .163 (2), c = 11.609 (2) Å , β = 103.91(1)° (at - 133 °C ). The strongly pseudocentrosymmetric structure shows a reversible phase transition at ca. 85 °C. The Os -Cl bond length (mean value 2.303 Å) in the regular [OsCl 6 ]-octahedra is significantly smaller than in [OsCl 6 ] 2− , in accordance with vibrational spectra. [(n -C 4 H 9 ) 4 N] 2 [Os 2 Cl 10 ] crystallizes in the orthorhombic space group Pbca with a = 15 .496 (2), b = 15 .965 (3), c = 19 .431(3) Å and contains centrosymmetric [Os 2 Cl 10 ] 2− ions with approximate D 2h symmetry. Within the edge-sharing [OsCl 6 ] octahedra the mean terminal and bridging Os -Cl bond lengths are 2.307 and 2.411 Å , respectively.