The Organometallic HyperTextBook Metal Alkyl Complexes Introduction Transition metal alkyl complexes play a critical role in a variety of important organometallic reactions such as olefin polymerization and hydroformylation. Early attempts to synthesize these complexes were unsuccessful, so it was originally thought that such species were inherently unstable due to weak metal-carbon bonds. More on this below. Structure and Bonding Simple alkyls are simple sigma donors, that can be considered to donate one or two electrons to the metal center depending on which electron counting formalism you use. For simple metal alkyls, the M-R bond distance is typically 190 to 220 pm.
Alkyls can bridge two metal centers, something that is well known from aluminum-alkyl chemistry.
Me groups at -75 degrees C in the 1 H NMR, but these coalesce and are one average signal at room temperature. This indicates a very low barrier to interconversion of the two groups. This non-linearity was ascribed to better orbital overlap on the basis of MO calculations. 136 Hz, indicating a fair amount of sp 2 character. Another type of unusual alkyl group involves agostic interactions in which part of the alkyl substituent coordinates to the metal in addition to the M-C bond.