Enantiomerically Pure Cyclopentadienyl- and Indenyl-Functionalized N-Heterocyclic Carbene Complexes of Iridium and Rhodium

Novel enantiomerically pure cyclopentadienyl- and indenyl-functionalized N-heterocyclic carbene ligands have been prepared by reaction of a chiral imidazole tosylate derivative with the corresponding cyclopentadienyl and indenyl lithium salts. Coordination of the Cp-functionalized NHC ligand to iridium and rhodium allowed the preparation of enantiomerically pure chelating cyclopentadienyl-functionalized Ir(III) and Rh(III) metal complexes. In contrast, the indenyl-functionalized NHC coordinates to iridium in a monodentate fashion, giving an Ir(I)-NHC complex containing a dangling indene group.