page_title: Decamethyldizincocene
section_title: Synthesis
hierarchical_section_title: Decamethyldizincocene / Synthesis
caption_attribution_description: English: Structural formula of the organozinc compound pentamethylcyclopentadienyl methyl zinc(II), Cp*Zn(CH3)
context_page_description: Decamethyldizincocene is an organozinc compound with the formula [Zn₂(η⁵–C₅Me₅)₂]. It is the first and an unusual example of a compound with a Zn-Zn bond. Decamethyldizincocene is a colorless crystalline solid that burns spontaneously in the presence of oxygen and reacts with water. It is stable at room temperature and especially soluble in diethyl ether, benzene, pentane, or tetrahydrofuran.
context_section_description: The ability of metals to form heteronuclear or homonuclear metal-metal bonds varies throughout the periodic table. Among the group 12 elements, mercury readily forms [M-M]²⁺ units whereas the elements cadmium and zinc form fewer examples of such species. Decamethyldizincocene was reported in 2004 by Carmona and coworkers as an unexpected product of the reaction between decamethylzincocene (Zn(C₅Me₅)₂) and diethylzinc (ZnEt₂).
  2 (η⁵-C₅Me₅)₂Zn + Et₂Zn → (η⁵-C₅Me₅)₂Zn₂ + 2 (η⁵-C₅Me₅)ZnEt + hydrocarbon(s)
  The analogous reaction of zincocene (Zn(C₅H₅)₂) with diethylzinc gives (η⁵-C₅H₅)ZnEt. Therefore, the stabilizing effect of the methyl groups on the cyclopentadienyl rings is of great importance in the formation of decamethydizincocene. The use of ZnEt₂ as a reactant is of particular significance.
  The organozinc precursor is important. Diphenylzinc (Zn(C₆H₅)₂), despite its lower solubility, can be utilized in place of ZnEt₂. On the other hand, ZnMe₂ gives only the half-sandwich compound [(η⁵-C₅Me₅)ZnMe].
  Both (η⁵-C₅Me₅)ZnEt and decamethyldizincocene are produced from the reaction between Zn(η⁵-C₅Me₅)₂ and ZnEt₂. The relative amounts depend on reaction conditions, which can be optimized to favor one or the other. For instance, if this reaction is conducted in pentane at -40 °C, (η⁵-C₅Me₅)ZnEt is the sole product. Conversely, if the reaction is conducted in diethyl ether at -10 °C, (Zn₂(η⁵-C₅Me₅)₂) is the major product.
caption: The half-sandwich compound [(η5-C5Me5)ZnMe]
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