Alkylidene and alkylidyne ligands

Alkylidene and alkylidyne ligands require metal-carbon p bonding in addition to s. This is different, however, form... 

COMPOUNDS WITH BRIDGING ALKYLIDENE AND ALKYLIDYNE LIGANDS. 

The reactions of alkylidenes (see Alkylidene) and alkylidynes (see Alkylidyne) of niobium and tantalum are typically characterized by nucleophilic alkylidene and alkylidyne ligands. Cp Ta(CH2SiMe3)2(=CHSiMe3) reacts with PhOH to give alkyl phenoxo Cp Ta(CH2SiMe3)3(OPh), and is hydrolyzed in the presence of a trace amount of H2O to give the 0x0 dialkyl derivative [Cp Ta(CH2SiMe3)20] . ... 

Alkylidene and alkylidyne ligands require metal-carbon ti bonding in addition to o (see Topic C6). This is different, however, from n complexes where bonding involves only the 7i orbitals of alkene or aromatic ligands. Examples are the ethene complex [(r 2-C2H4)PtCl3] (2) found in Zeise s salt, and... 

Clusters with Alkyl, Alkylidene, and Alkylidyne Ligands... 

For a general review of metal-ligand multiple bonds, see W. A. Nugent and J. M. Mayer, Metal-Ligand Multiple Bonds The Chemistry of Transition Metal Complexes Containing Oxo, Nitrido, Imido, Alkylidene, or Alkylidyne Ligands (New York, Wiley, 1988). 

It has already been seen that the reactivity of alkylidene and alkylidyne complexes may be dictated by the nature of both the metal and the carbon substitutents. These principles apply equally to alkene coordination (Figure 6.8). Two metal-ligand fragments serve to illustrate these principles in the activation of alkenes to electrophilic and nucleophilic... 

Discussion of the chemistry of carbon-based ligands is selective in order to emphasize more recent aspects of coordination chemistry. As a result, this section focuses on homoleptic alkyl complexes, as well as alkylidene and alkylidyne species that do not contain cyclopentadienyl or related ligands. Acyl (rj2-C,0-RCO) and iminoacyl (r/2-C./V-RCNR ) ligands are not discussed generally. These and other aspects of carbon-based ligands can be found in Comprehensive Organometallic Chemistry I and II.4 5... 

---