Unprecedented π-Bonded Rhodio- and Iridio-o-Benzoquinones as Organometallic Linkers for the Design of Chiral Octahedral Bimetallic Assemblies

We report the first synthesis of pi-bonded rhodio and iridio-o-benzoquinones [Cp*M(o-benzoquinone)] (M = Rh (3a); M = Ir (3b)) following a novel synthetic procedure. These compounds were fully characterized by spectroscopic methods; in particular the X-ray molecular structure of 3b was determined. Compounds 3a,b were used as chelating organometallic linkers for the design of a new family of chiral octahedral bimetallic complexes, 4-9. The X-ray molecular structure of [(bpy)(2)Ru(3b)][OTf](2) (5) is presented and shows that the organometallic linker 3b is chelating the ruthenium center. In particular, the carbocycle of the organometallic linker 3b adopts a eta(4)-quinone form, where the Cp*lr is also bonded to only four carbons. Further our strategy to design new assemblies with organometallic linkers is successfully achieved. These assemblies hold promise for new properties relative to those made from organic bidentate ligands.