16-electron amido complex

The dimeric amido complexes underwent reductive elimination after cleavage to form two monomeric, 3-coordinate, 14-electron amido complexes. In the case of the anilido dimer 20, a half-order rate dependence in the palladium complex showed that the reductive elimination occurred after reversible cleavage of the dimer to form two monomers. In the case of the f-butylamido complex 21, rapid reductive elimination occurred after irreversible dimer cleavage. This conclusion was supported by reaction rates that were first order in palladium dimer and by the lack of crossover during the reductive elimination reactions containing two doubly-labeled dimers. 

Fig. 2.16 Copper-amido complexes as catalysts for the intermolecular hydroamination of electron-deficient alkenes...

The imido complex [Mo2(cp)2(/r-SMe)3 (/u.-NFl)]" " 25+ undergoes an irreversible one-electron (EC) reduction [70]. Controlled potential electrolysis afforded the amido analog [Mo2(cp)2(/x-SMe)3(/x-NH2)] 26 almost quantitatively after the transfer of IF mol 25+. The amido complex was not the primary reduction product the latter was assigned as a rearranged imide radical (Sch. 18), which is able to abstract a FI-atom from the environment (supporting electrolyte, solvent, or adventitious water) on the electrolysis timescale. In the presence of protons, the reduction of 25+ became a two-electron (ECE) process. This is consistent with the protonation at the nitrogen lone pair of the primary reduction product, followed by reduction of the resulting amido cation... 

A key objective on our part was to complement material that had already been reviewed as well as to provide an overview of the key developments. Several reviews and commen-taries have appeared since the 1980 book and almost half of these have been published since 2000. These have dealt with, either fully or in part, derivatives of specific types of amido and related ligands, the applications of amido substituted complexes in chemical transformations, and the use of amido complexes as precursors for electronic materials or catalysis. The increasing interest in the use of multidentate amido and similar ligands of various types, which had been a notable development of mainstream amide chemistry since 1980, has resulted in the largest numbers of reviews. These cover ligands such as... 

R = R = Cy R = 1-adamantyl, R = CfiH 5. Te2-3,5 5 ). The vanadium analogue of the latter [V N(l-Ad)(C6H3Me2-3,5) 3] " 4 has also been characterized. Furthermore, a more efficient route to [Cr N(SiMe3)2 3] and a new crystal structure determination has been described. Three-coordinate metal amides have been treated in a general review that covers three-coordinate transition metal species with hard ligands. The electronic structure and bonding in tricoordinate amido complexes of transition metals have also been detailed... 

Figure 5-34. The deprotonation of an iron(m) complex of a macrocyclic amine to give an iron(m)-amido complex. The presence of the lone pair of electrons (negative charge) on the deprotonated nitrogen atom is emphasised ( ).

Figure 5-35. Tautomeric forms of the iron(in)-amido complex generated in Figure 5-34. The iron(n) complex 5.20 is simply a tautomeric form of 5.19, in which an electron has been transferred from nitrogen to the iron(m) centre.

However, the iron(m)-amido complex could also be written as an iron(n) amido radical complex 5.20. These two representations are, of course, simply limiting valence bond descriptions of the complex (Fig. 5-35). The difference simply involves the transfer of one electron from the lone pair on the nitrogen in 5.19 to the iron(ni) centre. 

Homoleptic amido complexes are also known. U(NMe2)6 is synthesized by a two-electron oxidation of... 

FIGURE 15. DPPF amido complexes with aryl groups of different electronic properties... 

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