Actinides organo compounds

Synthetic routes to compounds containing M-C o bonds are fairly obvious. Substitution of, e.g., Cl by CH, can be effected by treatment with LiCH3 or CH3MgBr. A number of reaction types mentioned in Chapter 9 - oxidative addition, reductive elimination, insertion and cyclometallation (Sections 9.6 and 9.7) - have their uses in preparative routes to M-C bonds. The formation of organo-compounds of the lanthanides and actinides is an area of growing interest. Preparative methods are similar to those for other ER species where E is of relatively low electronegativity, e.g. ... 

Mono(organo)nickel compounds, via oxidative addition, 8, 44 Monoorganotin hydroxides, preparation, 3, 850 Monoorganotin oxides, preparation, 3, 850 Mono(pentamethylcyclopentadienyl) actinide(IV) compounds, reactions, 4, 207 Mono(pentamethylcyclopentadienyl) lanthanide(III) compounds, synthesis and characteristics, 4, 66 Mono(pentamethylcyclopentadienyl) uranium(IV) sulfido complex, synthesis, 4, 207-208 Mono(phenoxy-aldehyde) trichlorides, with Zr(IV),... 

The alkyl phosphoric acids were first recognized as excellent actinide extractants because dibutyl phosphoric acid existed as an impurity in TBP (8). They extract well from unsalted solutions and from systems such as sulfate in which TBP is ineffective. Organo-phosphorus acids are thus suitable for uranium hydr metallurgical applications where ore is leached with sulfuric acid. The Dapex process is an example in which bis(2-ethylhexyl) phosphoric acid (HDEHP) is used alone or in synergistic combination with neutral organophosphorus compounds for uranium and vanadium recovery (9,10). 

Unlike the lanthanide complexes CpsLn, and many degradation products, Cp3 nLnXn, some actinide, and the majority of d-block metal, cyclopentadienides are not susceptible to reaction (1). A reasonably good test for the reactivity of metal-bonded Cp with H-acids consists in the addition of water or methanol. While all known lanthanide complexes will immediately be decomposed, many organo-uranium compounds of the type CP3UX either simply add H2O and/or undergo substitution of X (13) ... 

Siddall has pioneered the use of N, N disubstituted amides as extractants for tetra- and hexavalent actinides. The carbonyl oxygen in these compounds has enhanced basicity because of the presence of the amido nitrogen, and therefore should be analogous to the neutral organo-phosphorous compounds in extraction properties. 

The past decade has witnessed a dramatic expansion in what we know about the organometallic compounds of the 5f elements. It is now evident that the actinides have a very rich, intricate, and instructive organo-metallic chemistry, and that we have much to learn about the basic principles governing structure, bonding, and reactivity. Nowhere is this situation more obvious than in the area of metal hydrocarbyls (i.e., alkyls, aryls, alkenyls, etc.) and hydrides, and the growth in this area since our last ASI review in 1978 [ll has been phenomenal. 

Lanthanide and Actinide Elements.- The chemistry of organo-lanthan-Ide compounds, including Cp and indenyl complexes, has been re-... 

K. N. Raymond, C.W. Eigenbrot, Jr. - Stmctural Criteria for the Mode of Bonding of Organo-Actinides and -Lanthanide Compounds, Acc. Chem. Res. 13, 276,1980. 

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