Kenneth G. Moloy

The insertion of carbon dioxide into actinide alkyl and hydride bonds

Abstract This contribution reports on the insertion of CO 2 into actinide methyl and hydride bonds to yield acetate and formate complexes, respectively. Thus, addition of excess CO 2 to Cp′ 2 MMe 2 (Cp′ = η 5 - C 5 Me 5 , M = Th, U) results in the formation of Cp′ 2 - M(OAc) 2 complexes in high yield. These new complexes, which could also be prepared from Cp′ 2 - MCl 2 and 2 equiv. of NaOAc, were characterized by standard techniques. On the basis of infrared data and molecular weight measurements the bis(acetate) compounds are suggested to be monomeric with two bidentate acetate ligands, thus achieving a 10-coordinate geometry about the metal ion. The addition of only 1 equiv. of CO 2 to Cp′ 2 MMe 2 yields Cp′ 2 MMe(OAc) complexes exclusively, suggesting that the formation of the bis(acetate) complexes proceeds sequentially. These complexes could also be prepared via metathesis of the corresponding Cp′ 2 MMeCl complexes with NaOAc. Although the reaction of CO 2 with [Cp′ 2 Th(μ-H)(H)] 2 produces a variety of uncharacterizable products, Cp′ 2 Th(O 2 CH)(OCH-t-Bu) was formed upon treatment of Cp′ 2 Th(H)(OCH-t-Bu) with CO 2 .

Chemical and Physicochemical Properties of Actinide Organometallic Compounds. Catalytic and Stoichiometric Characteristics of Metal-Carbon and Metal-Hydrogen Bonds

ABSTRACT This article reviews recent results concerning the synthesis and properties of thorium and uranium hydrocarbyls and hydrides. With proper tuning of the actinide cordination sphere, organometallic compounds of exceptional reactivity can be prepared. Chemical transformations of the metal-carbon sigma bonds which are discussed include C-H activation, addition of ketones, protolysis, halogenolysis, and CO activation. Hydrogenolysis of the metal-carbon sigma bonds has afforded the first molecular actinide hydrides. The hydrides exhibit appreciable hydridic character. They also activate molecular hydrogen and olefins. The olefin activation and hydrogenolysis reactions can be coupled to effect homogeneous, catalytic olefin hydrogenation. The differences between thorium and uranium chemistry appear largely to reflect differences in accessible oxidation states and in metal-ligand bond polarity.