Uranium alkyl derivatives

Schlesinger H.C. Brown, Uranium Borohydride and its Alkyl Derivatives , in J J. Katz E. Rabinowitch, Eds, Chemistry of Uranium-Collected Papers , TID 5290, Book 1, USAEC, TISE (1958), 145-46 3) K.N. Semenenko... 

The uranium(III) complexes Cp2UI2(THF)3 and Cp UI2(py)3 have been structurally characterized [393b]. The similar tribromide complex Cp ThBr3(THF)3 [111] provides a convenient entry into the chemistry of mono(pentamethylcyclopentadienyl) derivatives of thorium. Aryloxide and alkyl derivatives may be readily prepared by treatment of Cp RhBr3(THF)3 with potassium aryloxide or alkyl Grignard reagents, respectively [373], for example (5.58)-(5.60) ... 

The high thermal stability of the metal-carbon bond in the actinide methyl derivatives suggests that a series of alkyl derivatives can be made. This does not prove to be the case. Reaction of C1M[N(SiMe3)2]3/ where M is thorium or uranium, with either ethyllithium or trimethylsilylmethyllithium at room temperature in diethyl ether yields the metallocycle (VI) and ethane or tetramethylsilane. A mechanism for this transformation, which involves a y-proton abstraction, is shown below. 

The photochemistry of U(C H ) R (R=CH, n-C H ) derivatives was first described by Giannotti, Marquette-Ellis, and Fischer. They observed that photolysis of uranium alkyl complexes in toluene and THF solutions at 60 C apparently results in the cleavage of the alkyl-uranium bonds and in the formation of a (C H ) U THF adduct ... 

Tetrakis-Cp uranium complexes are readily prepared via metathesis of UCl and KCp in refluxing benzene. These complexes are a relatively rare example of a pseudotetrahedral complex with four Tj -Cp rings, (rj-ring) (25). The Cp derivative has been shown to react with CO and CO2 to give acyl and carboxylato complexes. This complex also reacts with alkyl haUdes to afford the U(IV) complex, Cp UX (X = halide). 

Bromoanions, irivalent uranium, 34 98-99 Bromo complexes, osmium, 37 297-299 Bromocuprates(I), 37 39 Bromocyclophosphazene alkyl and aryl derivatives, 21 43 synthesis, 21 43, 44... 

The complexes [ N[CH2CH2NSiMc3]3 AnCl]2 (An = Th, U) were first reported the molecular structure of the uranium complex demonstrated it was dimeric in the solid state. The chloride ligand may be substituted, and derivatives incorporating cyclopentadienyl, borohydride, alkoxide, amide, and diazabutadiene derivatives have been characterized. Attempts to alkylate the... 

Derivation Finely ground ore is leached under oxidizing conditions to give uranyl nitrate solution. The uranyl nitrate, purified by solvent extraction (ether, alkyl phosphate esters), is then reduced with hydrogen to uranium dioxide. This is treated with hydrogen fluoride to obtain uranium tetrafluoride, followed by either electrolysis in fused salts or by reduction with calcium or magnesium. Uranium can also be recovered from phosphate sand. 

Camphene condensed with methyl propiolate under the influence of Lewis acids to give spiro-cyclobutene derivatives525 and with PCl2Me-AlCl3 to form C-3—C-8 bridged phosphorus adducts.526 Isocamphan-10-al condensed with rhodanine to yield a fungicidal product.527 Camphenyl-lithium can readily be converted into the tetra-alkyl-chromium or -uranium derivatives.528... 

Thus, while the coordinative saturation of the triscyclopentadienyl alkyls, alkenyls, alkynyls, and aryls (hydrocarbyls) of thorium and uranium, M(t75-C5H5) 3R (6.,Z L,9 ), affords considerably enhanced thermal stability over that of the simple homoleptic derivatives (10,11,12), it is at the expense of chemical reactivity. 

Tsutsui and Ely have extended the general method for preparing a-bonded actinide complexes to the synthesis of compounds containing lanthanide-carbon a-bonds (37,38,39). Using the reaction shown in eq.3, they synthesized a number of alkyl, aryl, and alkynyl derivatives. The metals chosen vary from Gd to Yb. Like their uranium analogs, they are oxygen and moisture sensitive, but they are surprisingly thermally stable. 

Preliminary studies indicate that these new dihalides can be converted to alkyl, aryl, and tetrahydroborate derivatives of varying stability (96, 99). Another useful precursor for some types of biscyclopentadienyl derivatives of uranium(IV) is the amido compound (C5H5)2U[N(C2H5)2]2 (100). 

The heat of hydrolysis can ignite the sohd alkoxides and can present a serions fire hazard. Any contact with water or exposnre of these snbstances to moist air shonld therefore be avoided. Among all the alkoxides, the compounds of alkali metals, especially the potassium derivatives, are the most reactive. Among the alkyl groups, the lower and branched alkyl groups form most reactive derivatives. A few heavy metal alkoxides, such as uranium hexa-fert-butoxide, does not react with water. 

Uranocene and its ring alkylated, 3-7 arylateds-io and annulatedn-i3 derivatives constitute the majority of the [8]annulene complexes known for the tetravalent actinides. The synthesis of the other bis([8]annulene)actinide(IV) complexes is similar to that of the uranium systems. 

The compounds (r/-CsHs)3UCl and (r/-CsHs)3ThCl are useful precursors for the synthesis of a large number of organoactinides, such as tris(cyclopentadienyl)metal alkoxides, tetrahydroborates, alkyls and aryls, halides, amides, and other derivatives,The chlorouranium compound was first synthesized by Reynolds and Wilkinson in 1956 from uranium tetrachloride and sodium cyclopentadienide in tetrahydrofuran. Vacuum sublimation, in our hands, invariably gives the pure product in low yield. The thorium analog was originally prepared in a similar manner,... 

---