REVERSIBLE BETA-HYDRIDE ELIMINATION OF AMINE LIGANDS FORMING STABLE CIS-ETA(2)-IMINIUM HYDRIDE OS-II COMPLEXES

Octahedral tetraammineosmium(II) species are generated from their Os-I II precursors containing an amine ligand cis to a labile alcohol or tr iflate. These compounds undergo reversible beta-hydride eliminations r esulting in the formation of cis-eta(2)-iminium hydride complexes. Jud ging from NMR data, the eta(2)-iminium group in these products lies pa rallel to the osmium-hydride bond with the iminium carbon eclipsing th e hydride. Attempts to form eta(2)-arene complexes of an Os-II ammine system bearing a stereogenic carbon are also described. (C) 1998 Elsev ier Science S.A.