Synthesis and Characterization of Rhodium Complexes with Phosphine-Stabilized Germylenes

The reaction of phosphine-stabilized germylenes (1a,b) with dimer complex [Rh2(μ-Cl)2(COD)2] leads to the corresponding phosphine–germylene–Rh­(I) complexes (2a,b). Interestingly, the stability of these complexes depends strongly on the nature of the substituent of the germylene fragment. Indeed, the complex (2a) with the chloro-germylene ligand isomerizes into a metallacycle rhodium complex (3a) via germylene insertion into the Rh–Cl bond, while the complex with the phenyl-substituted germylene (2b) was isolated and represents the first stable Rh­(I)–germylene complex with a Rh–Cl bond.