Uranium cyclopentadienyl complexes reactions

Uranium.— The thermolysis reactions of the alkyl complexes [UR( j-C6H6)3] are first order in uranium complex. Rate constants and free energies of activation are given in the Table. The order of stability of the alkyl compounds is primary > secondary > tertiary. In the thermolysis reaction intramolecular abstraction of hydrogen from a cyclopentadienyl occurs, giving RH with retention of configuration at carbon. ... 

A second example of a bis cyclopentadienyl uranium complex has resulted from the use of a bidentate, bridged bis(cyclopendadienyl) ligand to avoid further reaction to a tris species. It is prepared by the addition of the dianion of bis(cyclo-pentadienyl)methane to uranium tetrachloride in THE to give [CH2( — 5114)2]... 

The tris(cyclopentadienyl)thorium-, -uranium- and -plutonium chlorides are best prepared from TlCp in dimethoxyethane Np(Cp- )3Cl is formed in the Be(Cp)2 melt reaction . Analogous complexes containing bromide, iodide and/or indenyl ligands are prepared from K[Cp] or K[indenyl] and the appropriate MX4 compound (see Table 2). 

Reaction of tris-cyclopentadienyluranium(iv) chloride with two moles of Li(CH2)2PPha at — 50 °C affords the first actinide phospho-ylide complex. The new compound forms red, air- and moisture-sensitive crystals whose structure (1) has been determined from an JT-ray study. Two bis(cyclopentadienyl)uranium groups are essentially bridged by the ylide ligand, which is unique in that it also... 

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