Organoactinide chemistry

The growth of organoactinide chemistry, like that of organolanthanide chemistry, is comparatively... 

Organoactinide chemistry initially developed around the use of the ubiquitous cyclopentadienyl ligand (see Cyclopentadienyl), Cp = C5H5, and subsequently its alkyl- and silyl-substituted derivatives. The tetravalent oxidation state... 

The aforementioned preparative routes are not apphcable to mono-cot uranium(lV) complexes. The groups of Cloke, Streitwieser, and Ephritikhine have developed several successful routes for the preparation of such complexes some of these are indicated in equations (31-34). The displacement of a 7r-coordinated ligand under oxidizing conditions (equation 32) is quite remarkable and otherwise unprecedented in organoactinide chemistry. 

The pentamethylcyclopentadienyl ligand remains the most important ligand in organoactinide chemistry. It has been very successfully employed in the stabilization of novel organoactinide complexes and in organoactinide catalysis. 

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. 

Bums CJ, Eisen MS (2006) In Organoactinide Chemistry Synthesis and Characterization, Morss LR, Edelstein N, Fuger J (eds) The chemistry of the actinide and transactinide elements, 3rd edn. Springer, Berlin... 

The rapid growth of the organoactinide chemistry is intimately coupled with the use of the jr-coordinating cyclopentadienyl (Cp) or modified Cp ligands. Since the first report of the complex (CpjaUCl by Wilkinson [2], followed by Fischer s report of cyclopentadienyl compound of U and Th [42], a plethora of Cp actinide complexes have been synthesized. The most interesting part of this chemistry is that it is possible to coordinate one, two, three, or four Cp ligands in an j -coordination mode [43-48] and that it has the ability to stabilize a wide variety of oxidation states and coordination environments [3]. 

A number of reviews with relevant material have appeared. These include reviews on the application of lanthanide reagents in organic synthesis, structural trends of bis(pentaniethylcyclopentadienyl)lanthanide and ytrrium complexes, lanthanide and actinides (literature years 1987-89 and 199(pS), and recent advances in organoactinide chemistry. ... 

In 1983, Maurice Brookhardt and Malcolm Green published their concept of the intramolecular agostic C-H bond in complexes that feature a Lewis-acidic transition-metal center, i.e. those that possess a vacant coordination site. During the same year, Patricia Watson at the Du Pont company and John E. Bercaw at Caltech independently reported the activation of methane by d complexes of lanthanides and early transition metals (Lu and Sc respectively) according to the new a-bond metathesis mechanism (an intramolecular version being Schrock s a-elimination, in other d complexes, vide supra, which was developed by Tobbin Marks at Evanston with his seminal work in d° organoactinide chemistry also reported in 1982). 

The discovery in 1968 by Streitwieser and Muller-Westerhoff [52,53] that the dianion of cyclo-octatetraene, CgHl, can act as a ligand to the actinide elements signaled an important new development in organoactinide chemistry. The first compound of this class was uranocene, prepared by reaction of UCI4 with the potassium salt of cyclo-octatetraene (COT) ... 

ORGANOACTINIDE CHEMISTRY PROPERTIES OF COMPOUNDS HAVING METAL-CARBON BONDS ONLY TO 7t-BONDED LIGANDS... 

The Huckel (4n-l-2) n-electron dianion of cyclo-octatetraene, CgH, forms complexes with a number of early transition-metal and actinide ions. The synthesis of the uranium sandwich complex, U(CgHg)2 (bis([8]annulene)uran-ium(iv), known as uranocene ), was an important milestone in organoactinide chemistry. The green, pyrophoric compound was first prepared as shown below [7,124] ... 

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