Actinide complexes allyl

Raymond et al. reported the synthesis and structural analysis of an unusual actinide allyl complex, Cp UlCH C I ) ] (32). ... 

The allyl group is able to form both a- and jr-bonded complexes with the actinides. The 71 complexes will be considered here because of the similarities of the homoal-lyls with the lanthanide and actinide homoalkyls. The limiting modes of bonding in metal allyl complexes and the ratio of PMR intensities from magnetically equi valent protons are illustrated in Fig. 14. 

Actinide n-Complexes with Allyl, Cyclopolyene, Arene, and Related Ligands... 

Scandium group elements as well as the lanthanides form allyl complexes in which the central atom has H- 3 oxidation state, while the actinides give compounds possessing + 4 oxidation states (Table 7.14). These complexes are formed by reactions of metal halides with allyl compounds of magnesium, lithium, tin, etc. " " ... 

Complexes Containing Three-Electron n-Ligands Table 7.14. Allyl Complexes of the Group 3 Metals, the Lanthanides, and the Actinides ... 

Carbonyl complexes with actinides, 4, 192 (7 5-acyclic)Re(CO)3 complexes, 5, 919 allylation, 10, 663 with allylic tins, 9, 354 into 7 3-allyl palladium complexes, 8, 364 arene chromium carbonyls... 

The hydroamination of olefins has been shown to occur by the sequence of oxidative addition, migratory insertion, and reductive elimination in only one case. Because amines are nucleophilic, pathways are available for the additions of amines to olefins and alkynes that are unavailable for the additions of HCN, silanes, and boranes. For example, hydroaminations catalyzed by late transition metals are thought to occur in many cases by nucleophilic attack on coordinated alkenes and alkynes or by nucleophilic attack on ir-allyl, iT-benzyl, or TT-arene complexes. Hydroaminations catalyzed by lanthanide and actinide complexes occur by insertion of an olefin into a metal-amide bond. Finally, hydroamination catalyzed by dP group 4 metals have been shown to occur through imido complexes. In this case, a [2+2] cycloaddition forms the C-N bond, and protonolysis of the resulting metallacycle releases the organic product. 

The lanthanides and actinides also form a wide range of complexes with unsaturated organic ligands including allyls, cyclopentadienyls and cycloocta-tetraene derivatives. The bonding is strongly polar. Coordination numbers are determined largely by steric requirements around the metal centre. 

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. 

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