Planar "20-electron" osmium imido complexes. A linear imido ligand does not necessarily donate its lone pair of electrons to the metal

The authors have been using the (2,6-diisopropylphenyl)imido ligand as a stabilizing ligand for high-oxidation-state Mo alkylidene, W alkylidene, Re alkylidene, and Re alkylidyne complexes. In order to explore the potential of a similar approach to the high-oxidation-state organometallic chemistry of later metals, and in view of the relative scarcity of imido complexes of group 8 and 9 metals, we have begun to explore the preparation and chemistry of new imido complexes of osmium, the metal that yielded the first example of a transition-metal imido complex, Os(N-t-Bu)O{sub 3}.