Synthesis of new η 4 -hexafluorobenzene complexes of ruthenium and osmium from atoms of the metals: crystal structure of [Ru(η 6 -C 6 H 3 Me 3 -1,3,5)(η 4 -C 6 F 6 )]

Condensation of ruthenium or osmium atoms with mixtures of hexafluorobenzene and a second arene at –196 °C has given the novel compounds [M(η6-arene)(η4-C6F6)](M = Ru or Os; arene = C6H3Me3-1,3,5, C6H4Me2-1,3 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(η6-C6H3Me3-1,3,5)(η4-C6F6)] by an X-ray crystallographic study. The bis(hexafluorobenzene) compounds could not be prepared.