Actinide complexes hydrogenation

Hydrogenation with Early Transition Metal, Lanthanide and Actinide Complexes... 

In hydrogenation, early transition-metal catalysts are mainly based on metallocene complexes, and particularly the Group IV metallocenes. Nonetheless, Group III, lanthanide and even actinide complexes as well as later metals (Groups V-VII) have also been used. The active species can be stabilized by other bulky ligands such as those derived from 2,6-disubstituted phenols (aryl-oxy) or silica (siloxy) (vide infra). Moreover, the catalytic activity of these systems is not limited to the hydrogenation of alkenes, but can be used for the hydrogenation of aromatics, alkynes and imines. These systems have also been developed very successfully into their enantioselective versions. 

Hydrogenation Catalysts Based on Group III, Lanthanide, and Actinide Complexes I 131... 

Table 6.17 Hydrogenation of alkenes catalyzed by actinide complexes.

Finally, actinide complexes such as [MCp 2R2] (M = Th or U, R = alkyl or H) are very active catalysts for the hydrogenation and polymerization of olefins. The complexes [U(allyl)3X] (X = Cl, Br, I) are excellent initiators for the stereospecific polymerization of butadiene, which produces rubbers that have remarkable mechanical properties. Some other complexes are active for the heterogeneous CO reduction and alkene metathesis. The field of catalysis using organoactinide complexes should considerably expand in the near future. 

The purpose of this chapter is to survey and to analyze, in a necessarily brief and selective manner, actinide organometallic chemistry involving metal-carbon, metal-hydrogen, and metal-metal a bonds. Such linkages are fundamental building blocks of modem organometallic chemistry and catalysis. The nature of actinide complexes based upon coordination to multihapto organic n-electron systems was surveyed in Chapter 22. 

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