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.

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
Properties
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 C2h 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

See also

References
  1. McGrady, John E. (2000). "[(Cp*RuCl)2(μ-Cl)2]: bond-stretch or spin-state isomerism?". Angewandte Chemie International Edition. 39: 3077–3079. doi:10.1002/1521-3773(20000901)39:17<3077::AID-ANIE3077>3.0.CO;2-B.
  2. Kölle, Urich; Kossakowski, Janusz; Klaff, Norbert; Wesemann, Lars; Englert, Ulli; Herberich, Gerhard E. (1991). "Dichloro(pentamethylcyclopentadienyl)ruthenium—Novel Dichotomy in a Molecular Structure". Angew. Chem. Int. Ed. Engl. 30 (6): 690–691. doi:10.1002/anie.199106901.
  3. Kölle, Urich; Kossakowski, Janusz (1992). "Di-μ-Chloro-Bis[(η5-Pentamethylcyclopentadienyl) Chlororuthenium(III)], [Cp*RuCl2]2 and Di-μ-methoxo-Bis(η5-Pentamethylcyclopentadienyl)diruthenium(II), [Cp*RuOMe]2". Inorganic Syntheses. 29: 225–228. doi:10.1002/9780470132609.ch52.
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