Pentamethylcyclopentadienyl ruthenium dichloride dimer

Pentamethylcyclopentadienyl ruthenium dichloride is an organoruthenium chemistry with the formula [(C₅(CH₃)₅)RuCl₂]₂, commonly abbreviated [Cp*RuCl₂]₂. This brown paramagnetic solid is a reagent in organometallic chemistry. 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.^[1]

Pentamethylcyclopentadienyl ruthenium dichloride dimer

Names
IUPAC name Di-μ-chlorido-bis[chlorido(pentamethyl-η5-cyclopentadienyl)ruthenium(III)]
Other names Di-μ-chloro-bis[chloro(pentamethylcyclopentadienyl)ruthenium(III)] Dichloro(pentamethylcyclopentadienyl)ruthenium(III)
Identifiers
CAS Number	82091-73-4 Y
3D model (JSmol)	Interactive image monomer: Interactive image
ChemSpider	57426912
PubChem CID	170852889 monomer: 23290171
InChI InChI=1S/2C10H15.4ClH.2Ru/c2*1-6-7(2)9(4)10(5)8(6)3;;;;;;/h2*1-5H3;4*1H;;/q;;;;;;2*+2/p-4 Key: VDXZXHGAMPUNED-UHFFFAOYSA-J monomer: InChI=1S/C10H15.2ClH.Ru/c1-7-6-10(4,5)9(3)8(7)2;;;/h1-5H3;2*1H;/q-1;;;+2/p-2 Key: CHSNJSBMXZWKQT-UHFFFAOYSA-L
SMILES CC1=C([C](C(=C1C)C)C)C.CC1=C([C](C(=C1C)C)C)C.[Cl-].[Cl-].[Cl-].[Cl-].[Ru+2].[Ru+2] monomer: CC1=[C-]C(C(=C1C)C)(C)C.Cl[Ru]Cl
Properties
Chemical formula	C20H30Cl4Ru2
Appearance	brown solid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Preparation, structure, reactions

The compound has C_2h symmetry, with each metal atom having pseudo-octahedral geometry. In the crystal structure, two isomers are observed in the unit cell, 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.^[1][2]

It is prepared by the reaction of hydrated ruthenium trichloride with pentamethylcyclopentadiene.^[3]

2 Cp*H + 2 RuCl₃·3H₂O → [Cp*RuCl₂]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 [Cp*RuCl₂]₂ + 2 Zn → [Cp*RuCl]₄ + 2 ZnCl₂

Methoxide also can be used to produce a related diruthenium(II) derivative, which is also diamagnetic:

[Cp*RuCl₂]₂ + 3 NaOCH₃ + HOCH₃ → [Cp*RuOCH₃]₂] + 3 NaCl + CH₂O + HCl

Treating the tetramer with 1,5-cyclooctadiene in etheral solvent gives the mononuclear complex chloro(1,5-cyclooctadiene)(pentamethylcyclopentadienyl)ruthenium(II).^[4][5]

0.25 [Cp*RuCl]₄ + 1,5-cyclooctadiene → Cp*RuCl(1,5-cyclooctadiene)

Compounds like Cp*RuCl(1,5-cyclooctadiene), the tetramer [Cp*RuCl]₄, and related diamagnetic Cp*Ru(III) complexes have been investigated as hydrogenation catalysts.^[6]

See also

• (Cymene)ruthenium dichloride dimer - [(cymene)RuCl₂]₂
• Pentamethylcyclopentadienyl iridium dichloride dimer - [Cp*IrCl₂]₂