Pentamethylcyclopentadienyl ruthenium dichloride is an

organoruthenium chemistry Organoruthenium chemistry is the chemistry of organometallic compounds containing a carbon to ruthenium chemical bond. Several organoruthenium catalysts are of commercial interest and organoruthenium compounds have been considered for cancer therap ...

with the formula C₅(CH₃)₅)RuCl₂sub>2, commonly abbreviated p*RuCl₂sub>2. This brown

paramagnetic Paramagnetism is a form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. In contrast with this behavior, d ...

solid is a reagent in

organometallic chemistry Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali, alkaline earth, and transition metals, and so ...

. It is an unusual example of a compound that exists as isomers that differ in the intermetallic separation, a difference that is manifested in a number of physical properties.

Preparation, structure, reactions

The compound has C_2h

symmetry Symmetry (from grc, συμμετρία "agreement in dimensions, due proportion, arrangement") in everyday language refers to a sense of harmonious and beautiful proportion and balance. In mathematics, "symmetry" has a more precise definit ...

, with each metal atom having pseudo-

octahedral geometry In chemistry, octahedral molecular geometry, also called square bipyramidal, describes the shape of compounds with six atoms or groups of atoms or ligands symmetrically arranged around a central atom, defining the vertices of an octahedron. The oc ...

. In the

crystal structure In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions or molecules in a crystal, crystalline material. Ordered structures occur from the intrinsic nature of the constituent particles to form symmetric pat ...

, two isomers are observed in the

unit cell In geometry, biology, mineralogy and solid state physics, a unit cell is a repeating unit formed by the vectors spanning the points of a lattice. Despite its suggestive name, the unit cell (unlike a unit vector, for example) does not necessaril ...

, one with a 2.93 Å ruthenium–ruthenium bond and the other with a long internuclear distance of 3.75 Å. The former isomer is diamagnetic, and the latter is magnetic. It is prepared by the reaction of hydrated

ruthenium trichloride Ruthenium(III) chloride is the chemical compound with the formula RuCl3. "Ruthenium(III) chloride" more commonly refers to the hydrate RuCl3·''x''H2O. Both the anhydrous and hydrated species are dark brown or black solids. The hydrate, with a va ...

with

pentamethylcyclopentadiene 1,2,3,4,5-Pentamethylcyclopentadiene is a cyclic diene with the formula C5Me5H (Me = CH3). 1,2,3,4,5-Pentamethylcyclopentadiene is the precursor to the ligand ''1,2,3,4,5-pentamethylcyclopentadienyl'', which is often denoted Cp* (C5Me5) and read ...

. :2 Cp*H + 2 RuCl₃·3H₂O → p*RuCl₂sub>2 + 2 HCl + 6 H₂O The reaction is accompanied by formation of decamethylruthenocene. Pentamethylcyclopentadienyl ruthenium dichloride can reduced to the diamagnetic tetramer of Ru(II): :2 p*RuCl₂sub>2 + 2 Zn → p*RuClsub>4 + 2 ZnCl₂ Methoxide also can be used to produce a related diruthenium(II) derivative, which is also diamagnetic: : p*RuCl₂sub>2 + 3 NaOCH₃ + HOCH₃ → p*RuOCH₃sub>2] + 3 NaCl + CH₂O + HCl Treating the tetramer with 1,5-Cyclooctadiene, 1,5-cyclooctadiene in etheral solvent gives the mononuclear complex chloro(1,5-cyclooctadiene)(pentamethylcyclopentadienyl)ruthenium(II). :0.25 p*RuClsub>4 + 1,5-cyclooctadiene → Cp*RuCl(1,5-cyclooctadiene) Compounds like Cp*RuCl(1,5-cyclooctadiene), the tetramer p*RuClsub>4, and related diamagnetic Cp*Ru(III) complexes have been investigated as

hydrogenation catalysts Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic co ...

.{{Cite journal , last=Fürstner , first=Alois , date=2019-01-09 , title=trans -Hydrogenation, gem -Hydrogenation, and trans -Hydrometalation of Alkynes: An Interim Report on an Unorthodox Reactivity Paradigm , url=https://pubs.acs.org/doi/10.1021/jacs.8b09782 , journal=Journal of the American Chemical Society , language=en , volume=141 , issue=1 , pages=11–24 , doi=10.1021/jacs.8b09782 , issn=0002-7863

References

Metallocenes Organoruthenium compounds Dimers (chemistry) Pentamethylcyclopentadienyl complexes Chloro complexes Ruthenium(III) compounds

Preparation, structure, reactions

See also

References