SYNTHESIS OF NEW ETA-4-HEXAFLUOROBENZENE COMPLEXES OF RUTHENIUM AND OSMIUM FROM ATOMS OF THE METALS - CRYSTAL-STRUCTURE OF [RU(ETA-6-C6H3ME3-1,3,5)(ETA-4-C6F6)]

Condensation of ruthenium or osmium atoms with mixtures of hexafluorob enzene and a second arene at -196-degrees-C has given the novel compou nds [M(eta6-arene)(eta4-C6F6)] (M = Ru or Os; arene = C6H3Me3-1,3,5, C 6H4Me2-1,3 or C6H6), these being further examples of compounds with a partially co-ordinated hexafluorobenzene ligand. The hapticity of the arene rings was determined from their proton and fluorine NMR spectra. This was confirmed for the specific case of [Ru(eta6-C6H3Me3-1,3,5)(e ta4-C6F6)] by an X-ray crystallographic study. The bis(hexafluorobenze ne) compounds could not be prepared.