Reaction with actinide halides

Alkoxide and aryloxide ligands are excellent ligands for the actinides. As a result, these ligands have been studied extensively in the coordination chemistry and reactivity of tri-, tetra-, penta-, and hexavalent actinides. The alkoxides and aryloxides can be synthesized by a variety of routes the two most popular routes include direct reaction of actinide halides with alkali metal salts of the alkoxide or aryloxide of interest and protonolysis of actinide amides by alcohols. 

Reactions of phosgene with actinide halides and oxide halides... 

Excellent quality metal, comparable to that from the halide reduction, can be prepared by this technique. A big advantage is that no neutrons are present from (a,ra) reactions on fluorine nuclei, in marked contrast to the case with actinide fluorides. 

Actinide hydrides are rather hydridic and nndergo rapid reactions typical of snch systems for example, reactions with ketones and halocarbons provide actinide alkoxides and halides, respectively. Rapid qnantitative addition of terminal alkenes (the reverse of /S-hydride elimination) is consistent with the known bond disruption enthalpies (eqnation 66). ... 

The small steric size and propensity of cyanide groups to bridge metal centers have limited their use as ligands in molecular coordination chemistry of the actinides, where they are prone to form amorphous polymeric products. Limited metathesis studies have been conducted. Reaction of tetravalent halides with alkali metal cyanides in liquid ammonia is reported to give rise to a product of the formula UX3(CN)-4NH3, whereas use of the larger thorium ion yields unidentified products. 

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. " " ... 

Cyclopentadienyl organometallic compounds can be prepared by a variety of reactions [49, 50]. The general method for actinides in the in and iv oxidation states is by reaction of potassium or sodium cyclopentadienide with the anhydrous actinide halide (AnX ) in an organic solvent such as tetrahydrofuran (THF), benzene, or diethyl ether. 

Halides of divalent actinides are obtained by reaction of the metal with a stoichiometric amount of HgX2 (X = Cl, Br, I) ... 

In its precipitation reactions ameiicium(IIl) is very similar to the other tripositive actinide elements and to the rare earth elements. Thus the fluonde and the oxalate are insoluble and the phosphate and iodate are only moderately soluble in acid solution, whereas the nitrates, halides, sulfates, sulfides, and perchlorates are all soluble. Americium(VI) can be precipitated with sodium acetate giving crystals isostructural with sodium uranyl acetate,... 

Oxidative addition of organic halides to low-valent metal complexes generates reactive metal alkyls that can then be used in insertion, coupling, carbonylation-decar-bonylation and cyclization reactions for organic synthesis. These transformations can be made catalytic after development of the stoichiometric chemistry using the more stable metal alkyls. This section surveys the reactions of alkyl, aryl and acyl halides with transition metal complexes of the groups IIIA (lanthanides and actinides), IVA-VIII and IB. 

The intermetallic compounds are synthesized by heating mixtures of actinide oxides or halides with finely divided noble metal powders in pure hydrogen. Protactinium metal was prepared in a modified version of the van Arkel-de Boer procedure protactinium iodide, formed by reaction between iodine and protactinium carbide, was thermally dissociated on a resistance heated tungsten wire (6,7) ... 

Related complexes are obtained with Pd, where one face of a benzene ring is shared by two Pd atoms . Mono-f/ -benzene ligands on a pentacobalt cluster also form from the aluminum halide-aluminum metal conditions . The preparation of -arene complexes of the lanthanides and actinides has been more diflScult, presumably because of the proclivity of these metals to form ionic bonds. Reactions between hexamethylbenzene and metal halides in the presence of AlClj-Al or AlCl-Zn reagents in the isolation of a mononuclear Sm complex, in addition to di- and trinuclear U complexes. ... 

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