Chlorobis(triphenylphosphine)ruthenium is the organoruthenium half-sandwich compound with formula RuCl(PPh₃)₂(C₅H₅). It as an air-stable orange crystalline solid that is used in a variety of organometallic synthetic and catalytic transformations.

Structure and Properties

The compound has idealized C_s symmetry. It is soluble in chloroform, dichloromethane, and acetone.

Preparation

Chloro(cyclopentadienyl)bis(triphenylphosphine)ruthenium was first reported in 1969 when it was prepared by reacting dichlorotris(triphenylphosphine)ruthenium(II) with cyclopentadiene.

RuCl₂(PPh₃)₃ + C₅H₆ → RuCl(PPh₃)₃(C₅H₅) + HCl

It is easily prepared from ruthenium(III) chloride

Ruthenium(III) chloride

Ruthenium chloride is the chemical compound with the formula RuCl3. "Ruthenium chloride" more commonly refers to the hydrate RuCl3·xH2O. Both the anhydrous and hydrated species are dark brown or black solids...

, triphenylphosphine

Triphenylphosphine

Triphenylphosphine is a common organophosphorus compound with the formula P3 - often abbreviated to PPh3 or Ph3P. It is widely used in the synthesis of organic and organometallic compounds. PPh3 exists as relatively air stable, colorless crystals at room temperature...

, and cyclopentadiene

Cyclopentadiene

Cyclopentadiene is an organic compound with the formula C5H6. This colorless liquid has a strong and unpleasant odor. At room temperature, this cyclic diene dimerizes over the course of hours to give dicyclopentadiene via a Diels–Alder reaction...

 in ethanol.

Reactions

Chloro(cyclopentadienyl)bis(triphenylphosphine)ruthenium(II) undergoes a variety of substitution reactions often by involving substitution of the chloride. With phenylacetylene it gives the phenyl vinylidene complex.

(C₅H₅)(PPh₃)₂RuCl + HC₂Ph + NH₄[PF₆] → [Ru(C:CHPh)(PPh₃)₂(C₅H₅)][PF₆] + NH₄Cl

Displacement of PPh₃ by carbon monoxide affords a chiral

Chirality (chemistry)

A chiral molecule is a type of molecule that lacks an internal plane of symmetry and thus has a non-superimposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom....

 compound.
(PPh₃)₂RuCl + CO → (C₅H₅)(PPh₃)(CO)RuCl + PPh₃

The compound can also be converted into the hydride

Hydride

In chemistry, a hydride is the anion of hydrogen, H−, or, more commonly, a compound in which one or more hydrogen centres have nucleophilic, reducing, or basic properties. In compounds that are regarded as hydrides, hydrogen is bonded to a more electropositive element or group...

.
(PPh₃)₂RuCl + NaOMe → (C₅H₅)(PPh₃)₂RuH + NaCl + CH₂O

Applications

Chloro(cyclopentadienyl)bis(triphenylphosphine)ruthenium(II) serves as a catalyst for a variety of reactions. For example, in the presence of NH₄PF₆ it catalyzes the isomerisation

Isomerisation

In chemistry isomerisation is the process by which one molecule is transformed into another molecule which has exactly the same atoms, but the atoms are rearranged e.g. A-B-C → B-A-C . In some molecules and under some conditions, isomerisation occurs spontaneously...

of allylic alcohols to the corresponding saturated carbonyls.