Actinide pentamethylcyclopentadienyl

The purpose of this article is to review recent results on the carbonylation chemistry of actinide-to-carbon sigma bonds, bearing in mind the unique properties of 5f-organometallics cited above. We focus our attention on the properties of bis(pentamethylcyclopentadienyl) actinide acyls. Just as transition metal acyls (A) occupy a pivotal role in classical carbonylation chemistry, it will be seen that many of the unusual... 

This article reviews recent results on the chemical, spectral and structural properties of bis(pentamethylcyclopentadienyl) thorium and uranium dihaptoacyl complexes produced by migratory insertion of carbon monoxide into actinide-carbon sigma bonds. 

The conversion of CO + H2 (syn-gas) to hydrocarbons and oxygenates (Fischer-Tropsch chemistry)119 is of considerable industrial importance and recently the activation and fixation of carbon monoxide in homogeneous systems has been an active area for research.120,121 The early transition elements and the early actinide elements, in particular zirconium124 and thorium,125 126 supported by two pentamethylcyclopentadienyl ligands have provided a rich chemistry in the non-catalytic activation of CO. Reactions of alkyl and hydride ligands attached to the Cp2M centers with CO lead to formation of reactive tf2-acyl or -formyl compounds.125,126 These may be viewed in terms of the resonance forms (1) and (2) shown below. 

Bis(pentalene) uranium complexes, preparation, 4, 221—222 Bis(pentamethylcyclopentadienyl)actinide(IV) compounds, synthesis and reactions, 4, 210 Bis(pentamethylcyclopentadienyl)actinide(V) compounds, synthesis and reactions, 4, 210 Bis(pentamethylcyclopentadienyl)actinide(VI) compounds, synthesis and reactions, 4, 210... 

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),... 

Pentamethylcyclopentadienyl complexes CpjAnX, 4, 207 Cp AnX2 and Cp AnX, 4, 206 Cp MX compounds, 4, 62 with iridium amidinates, 7, 366 mono(Cp ) actinide(IV) compounds, 4, 207 with Ni-C cr-bonded ligands, 8, 108-109 with rhodium, 7, 152 with ruthenium, 6, 632 tris(Cp ) actinide(IV) compounds, 4, 219 with zirconium amidinates, 12, 730 l, 2, 3, 4, 5 -Pentamethyl-l-formylruthenocene, preparation, 6, 643... 

Unusual mono(pentamethylcyclopentadienyl)actinide complexes containing a 15-membered trianionic hexaoxo ligand built from catechol and catecholborate have been prepared and structurally characterized. As depicted in Scheme 36, the synthesis of these complexes has been achieved by reacting Cp 2AnMe2 (An = Th, U) with an excess of catecholborane that contains 5% dimethylsulfide (DMS) in benzene at room temperature for 24 h. The DMS ligand could be replaced by THF.95... 

The question of how much steric crowding is possible in tris( 75-pentamethylcyclopentadienyl)actinide complexes has been addressed by the synthesis of the hitherto unknown compounds Cp 3UCl and Cp 3UF. Reaction of Cp 3U with 1 equiv. of PhCl gives Cp 3UC1 as the primary product (Scheme 63). Upon addition of another equivalent of PhCl this... 

The lanthanides and actinides are also active in electrophilic attack on arenes. Bis(pentamethylcyclopentadienyl)lutetium methyl or hydride complexes react readily with benzene to give phenyl complexes and methane or dihydrogen . Similar reactions are observed for Sc and Th In a remarkable reaction benzene can be dimetallated by Lu, yielding II ... 

Bis (pentamethylcyclopentadienyl) actinide (IV) mono- and dialkyl complexes are readily prepared from A... 

Although the monomeric complexes of actinides with N, P or O donor Hg-ands are stable and could be synthesized without much problem, mono- and dithiol complexes are very difficult to synthesized because they tend to support a monomer-dimer equilibrium [244]. Only lately have a few complexes of bis(pentamethylcyclopentadienyl) metallocene dithiolates, (Ti -C5Me5)2 Th(SPr)2 [202] and (ii5-C5Me5)2U(SR)2 (where R = Me, f-Pr, t-Bu, Ph) [284] appeared. 

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