Uranium organometallic complexes

As an illustrative example taken from the current literature, consider the variation of C-C and C-O bond lengths in the deltate species CsO2- held within a dinuclear organometallic uranium(IV) complex. In a remarkable synthesis, this cyclic aromatic oxocarbon dianion is generated by the metal-mediated reductive cyclotrimerization of carbon monoxide, as indicated in the reaction scheme... 

Bums and coworkers have discovered a remarkable reaction involving Cp 2U(Me)Cl. Treatment of the latter with l-lithio-l,2-diphenylhydrazine in ether solution generates lithium chloride and methane, and provides the uranium(VI) bis-imido compound Cp 2U(NPh)2, conceivably via a uranium(lV) hydrazido species Cp 2U( ] -PhNNPh)." A plausible reaction sequence is laid out in equations (61) and (62). Cp 2U(NPh)2 was the first uranium(Vl) organometallic complex. In the solid state, Cp 2U(NPli)2 adopts the famihar... 

Organometallic complexes of uranium(vi) with organoimido and oxo functional groups Cp 2U(=NR)(=E) (E = NR or O) have also been prepared by two-electron oxidative atom transfer using organic azides, amine A-oxides or nitrous oxide. Another way of generating the compounds is reductive cleavage of 1,2-disubstituted hydrazines (Scheme 54).119-121... 

After ferrocene, a large number of related molecules have been prepared—even some in which uranium is the metal. There is now an entire subset of transition-metal organometallic complexes known as metallocenes based on cyclopentadieifide ligands. These compounds are not only structurally interesting, but many of them have useful applications as catalysts for industrial processes. 

The first actinide organometallic complex, red-brown (C5H5)3UC1, was prepared and characterized by Reynolds and Wilkinson in 1956 or shortly after the discovery of ferrocene see Ferrocene, (C5H5)2pe. However, it was not until the preparation and structural characterization of bis(cyclooctatetraenyl)uranium, (C8H8)2U ( uranocene , see Uranocene) in 1968 and the isolation and characterization of uranium alkyls see Alkyl Complexes) in 1973 that the field developed momentum. The purpose of this chapter is to provide an overview of organoactinide chemistry that reflects historical as well as recent developments and achievements in the field it is not meant to be an exhaustive review of the primary literature. More detailed discussion, background material, and extensive references to the literature can be found in several excellent reviews. 

Yttrium organometallics, NRM spectroscopy Lutetium organometallics, NMR spectroscopy Lanthanum organometallics, NMR spectroscopy Samarium organometallics, NMR spectroscopy Uranium organometallics, NMR spectroscopy Diastereotopic systems, NMR spectroscopy Carbon-13 NMR spectroscopy, paramagnetic complexes Agostic interactions, NMR spectroscopy... 

Coffinite was first described as a new mineral by Stieff and co-workers from several localities in the sandstones of the Colorado Plateau deposits often intimately associated with asphaltic material. It was also found in vein-type deposits in Spain by Arribas and has since been found in almost all types of deposits. The composition has been reported as U(SiOi4)i AOrganic matter was always present and organometallic complexes of uranium may have accounted for the excess uranium rather than requiring excess (OH) to account for the U Si ratio deviating from unity. USi04 has been prepared by Fuchs and Gebert with no evidence of OH substitution. 

Matson EM, Forrest WP, Fanwick PE, Bart SC. Use of alkylsodium reagents for the synthesis oftrivalent uranium alkyl complexes. Organometallics. 2012 31 4467-4473. 

ManseU SM, Famaby JH, Germeroth AI, Arnold PL. ThermaUy stable uranium dinitrogen complex with sUoxide supporting Hgands. Organometallics. 2013 32 4214-4222. 

Duhovic S, OriaJV, Odoh SO, Schreckenbach G, Batista ER, Diaconescu PL. Investigation of the electronic stmcmre ofmono(l,lCdiamidoferrocene) uranium(IV) complexes. Organometallics. 2013 32 6012-6021. 

Monreal MJ, Diaconescu PL. A weak interaction between iron and uranium in uranium alkyl complexes supported by ferrocene diamide ligands. Organometallics. 2008 27 1702-1706. 

Bilinear chemometrics methods, 6 39-57 Billet products, titanium, 24 858 Bill of Material, 15 460, 470 Bills of lading, 25 330 Bimetal complexes, 16 88 Bimetallic deactivation processes, 16 93-94 Bimetallic fluorides, 15 396 Bimetallic metal nitrides, 17 199 Bimetallic organometallic uranium complexes, 25 442 Bimetallic organometallic thorium complexes, 24 773-774... 

Many substituted uranocenes have been made and there is a substantial body of organometallic chemistry of uranocene derivatives now known 16, 17). Some of this chemistry will be mentioned in passing but wiU not be covered in a systematic way since other reviews of the organic chemistry are available 18). The only other actinide cyclooctatetraene complex structurally characterized to date is bis[(l,3,5,7-tetramethylcyclooctatetraenyl]uranium(IV) 19), which was of interest because the presence of methyl groups allowed the planarity and relative orientation of the dianion rings to be determined. Crystal and molecular parameters for these three actinide compounds are summarized in Table 1. 

Ketoenolates have not been isolated for the tripositive elements in the attempted preparation of Pu(MeCOCHCOMe)3, oxidation to plutonium(IV) occurred very readily.17 Complexes with ethers appear to be restricted to THF solvates apart from UC13-THF, a useful starting material for uranium(III) preparative chemistry,18 the only other examples are solvated organometallic compounds, such as Cp3Np-3THF and Cp3PuTHF. 

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