Gmelin: Handbook of Inorganic and Organometallic Chemistry: OS - Organoosmium Compounds: Supplement Vol A: Part B6

Two thirds of the volume are devoted to triosmium carbonyl compounds, generally containing a triangular Os3 core, in which additional ligands are bonded to osmium by one 2- or 3- bridging carbon atoms. Prominent examples of ligands with 2- bridging carbon atoms are bridging carbenes, but in addition bridging aryl groups or heterocycles. In many cases the ligand is additionally coordinated to osmium by heteroatoms. Almost all ligands with 3- bridging carbon atoms are of the carbyne type, leading to pseudotetrahedral Os3C molecular cores. The final section deals with heterometallic carbonyl compounds containing additional ligands bonded by one carbon atom, mostly in a bridging manner. Most of the compounds in this volume are structurally well characterized. Their reactions often are accompanied by unexpected rearrangement either of the cluster core or of the ligands.