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′ 2MMe 2 (Cp′ = η 5- C 5Me 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′ 2MMe 2 yields Cp′ 2MMe(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′ 2MMeCl complexes with NaOAc. Although the reaction of CO 2 with [Cp′ 2Th(μ-H)(H)] 2 produces a variety of uncharacterizable products, Cp′ 2Th(O 2CH)(OCH-t-Bu) was formed upon treatment of Cp′ 2Th(H)(OCH-t-Bu) with CO 2.