(Cymene)ruthenium dichloride dimer
(Cymene)ruthenium dichloride dimer, often abbreviated as [(cymene)RuCl2]2, is an organometallic compound that is a common precursor in organoruthenium catalysis. It is an air-stable, orange-to-red solid, soluble in organic solvents like dichloromethane and chloroform. Its structure consists of two ruthenium atoms, each coordinated to a cymene ligand (specifically para-cymene) and two chloride ligands. The "dimer" designation indicates that two of these Ru(cymene)Cl2 units are associated, bridged by the chloride ligands. These chloride bridges are labile and readily cleaved by Lewis bases, allowing the formation of mononuclear ruthenium complexes that are catalytically active.
Synthesis of (cymene)ruthenium dichloride dimer typically involves the reaction of ruthenium trichloride hydrate (RuCl3·xH2O) with para-cymene in a suitable solvent, often ethanol or isopropanol. The reaction may require a reducing agent to facilitate the formation of the ruthenium(II) species. The product precipitates as a solid and can be purified by recrystallization.
This compound is widely employed as a starting material for the synthesis of other ruthenium complexes. The cymene ligand provides steric bulk and influences the reactivity of the ruthenium center. The chloride ligands can be easily displaced by other ligands, such as phosphines, amines, or carbenes, allowing the creation of a wide variety of catalysts.
Applications of complexes derived from (cymene)ruthenium dichloride dimer include transfer hydrogenation, C-H activation, and olefin metathesis. The catalytic activity and selectivity of these complexes can be tuned by modifying the ligands bound to the ruthenium center. Its relative air stability and ease of handling compared to other organoruthenium compounds make it a popular choice in both academic and industrial research.