Darstellung und Charakterisierung von Tetrakis(Chloro-Bromo)-Oxalato-Osmaten(IV)

Preparation and Characterization of Tetrakis(chloro-bromo) Oxalatoosmates(IV) On treatment of OsBr₄ox]^2? with Cl^? the yellow to orange coloured complexes OsCl_nBr_4?nox]^2?, n = 1, 2, 3, are formed. The separation of geometric isomers is difficult but possible by ion exchange chromatography on diethylaminoethyl cellulose. The 10 K absorption spectra show in the UV/VIS region intensive Br←Os and Cl←Os charge transfer bands and in the NIR weak intraconfigurational transitions splitted by spin-orbit coupling and lowered symmetry into 5 components. A very weak spin-forbidden d—d-transition at about 600 nm is improved as a luminescence absorption band in the Raman spectrum.