Efficient and Rapid Synthesis of Chlorido-Bridged Half-Sandwich Complexes of Ruthenium, Rhodium, and Iridium by Microwave Heating

The dinuclear complexes [(p-cymene)RuCl2]2 and [(cyclopentadienyl)MCl2]2 (M = Ru, Rh, Ir) are important starting materials in organometallic chemistry. The standard synthesis of these complexes involves heating of an alcoholic solution of RuIII, RhIII, or IrIII salts with precursors of the π-ligands for several hours under reflux. Microwave heating allows these complexes to be obtained within a few minutes without compromising the yields. Furthermore, the microwave-assisted syntheses require less solvent and, in some cases, lower amounts of ligand precursors.