(Cymene)ruthenium dichloride dimer is the organometallic compound with the formula [(cymene)RuCl₂]₂. This red-coloured, diamagnetic solid is a reagent in organometallic chemistry and homogeneous catalysis.

Preparation and reactions

The dimer is prepared by the reaction of the phellandrene with hydrated ruthenium trichloride.^[1] Upon heating, [(cymene)RuCl₂]₂ undergoes exchange with other arenes, releasing free p-cymene. This dimeric molecule cleaves easily in the presence of Lewis bases to give monomeric adducts:

[(cymene)RuCl₂]₂ + 2 PPh₃ 2 (cymene)RuCl₂(PPh₃)

Such monomers adopt pseudo-octahedral piano-stool structures.

Treatment of [(cymene)RuCl₂]₂ with the chelating anionic ligand precursor TsDPENH gives (cymene)Ru(TsDPEN-H), a catalyst for asymmetric transfer hydrogenation.^[2]

New catalysts

[(cymene)RuCl₂]₂ is also used to prepare catalysts (by monomerization with dppf) used in borrowing hydrogen catalysis^[3], a catalytic reaction that is based on the activation of alcohols towards nucleophilic attack.

References

1. ↑ Bennett, M. A.; Huang, T. N.; Matheson, T. W. , Smith, A. K. "( ⁶-Hexamethylbenzene)ruthenium Complexes", Inorganic Syntheses, 1982, volume 21, pages 74 8.
2. ↑
3. ↑ Hamid et al.; Advanced Synthesis & Catalysis Volume 349, Issue 10, pages 1555 1575, July 2, 2007;