A metal-alkyl complex is a molecule that contains at least one metal-alkane bond.
Contents
History
The first reported example of a complex containing a Metal-sp3 carbon bond was the synthesis of Magnesium-Bromide containing "Grignard Reagents" by Victor Grignard in 1899.
Chemical Properties
The difference in electronegativity across a metal-alkane bond can vary greatly, from highly ionic in character (NaCH3) to almost completely covalent(AuCH3), as such the chemical reactivities and stabilities of such compounds vary greatly. On one extreme, Carbon-Alkyl Metal Bonds are extremely reactive, for example n-butyllithium is highly reactive, pyphoric and a commonly used reagent in organic synthesis, on the other extreme, Carbon-Lead bonds are close to covalent bonds and compounds such as Tetraethyllead are ambient stable.
β-hydride elimination
One major determinant the kinetic stability of Metal-Alkyl complexes is the presence of Hydrogen at the Beta position relative to the Metal. If such hydrogens are present then the metal center can promote their elimination to form a metal-alkene complex, which is less kinetically stable than a metal alkane complex. This process is of interest as many catalytic processes can undergo competing β-hydride elimination to form unwanted side products.
Catalysis
Grignard Reagents are common carbon sources in organic synthesis using catalysis.
Methylaluminoxane is commonly used as a co-catalyst in Zigler-Natta catalysis, which is an important industrial process used to make polyalkenes from olefins.