Alkyls actinide

Marks TJ, Yang W, Stern CL (1991) Models for organometallic molecule-support complexes. Very large counterion modulation of cationic actinide alkyl reactivity. Organometallics 10 840-842... 

From the relative stabilities of the actinide homoalkyls or -allyls and the tris(cyclopentadienyl) actinide alkyls, it appears that a coordinatively saturated metal center is necessary for kinetic stability. In contrast to f-transition metal alkyls, the absence of hydrogens appears to be of minor importance. In the case of the lanthanide alkyls and the tetrabenzylthorium, where the formal coordination number is only four, the steric bulkiness of the Hgands must be responsible for their observed thermal stability. 

Question 13.2 Why are simple actinide alkyls rare in view of the number of lanthanide species like [M CH(SiMe3)2 3], [LnPh3(thf)3], and [LnMeel (see Chapter 5) ... 

One other approach for the activation of alkane C-H bonds is to choose a metal that forms a strong metal-to-carbon bond. Main group and early J-block elements (e.g., AIR3, TaRs, etc.) as well as lanthanide and actinide alkyls fall into this category. 

Scheme 4 Sigma bond metathesis of actinide-alkyl bonds...

In constructing any mechanistic scheme to describe the thermal decomposition of actinide alkyls, the first questions which arise are why -hydride elimination does not occur in (C5H5)3UR and (C5H5)3ThR complexes and whether this behavior is a fundamental property of all actinide alkyl complexes. In order to answer these questions, we examined... 

The triscyclopentadienyl alkyls and the tetraalkyls represent two extremes in actinide alkyl chemistry. The former are thermally stable and relatively nonlabile whereas the latter are thermally unstable and labile. It is of interest to determine whether some intermediate compromise in these characteristics can be achivede by suitable choice of supporting ligands. 

A number of actinide alkyl and hydride CO activation patterns also suggest the intermediacy of carbonyl complexes along the respective reaction coordinates (vide infra). 

Exclted states, primary processes Lanthanides, electronic structure Lanthanides, excited states Lanthanides, photochemistry Actinides, electronic structure ActlnldCs, excited states Uranyl ion, photochemistry Uranyl complexes, photochemistry Uranyl Ion, luminescence quenching Photochemistry, actinide alkyls... 

B-Itydrogen elimination, photolnduced In actinide alkyls Homolysls, photolnduced in actinide alkyls... 

Insertion of two equivalents of CO into [(C6Me5)2ZrMe2] results in an unusual metallocycle (Scheme 11). (c/. formation of an analogous metallocycle with actinide alkyls. )... 

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