New stoichiometric and catalytic organometallic chemistry with actinides. CH activation and phosphine/phosphite coordination chemistry

This short review highlights two areas of recent activity in organoactinide chemistry: actinide-centered homogeneous chemistry in which intra- and intermolecular CH activation takes place on hydrocarbon fragments, and actinide coordination chemistry involving phosphine and phosphite ligands. It is shown that new metal-ligand bond enthalpy data afford a far greater understanding of observed CH activation patterns, and, moreover, support the design of successful new strategies for CH activation on exogenous hydrocarbon molecules. For example, the strain energy of a thoracyclobutane provides the driving force for ring-opening reactions that involve attack on a alkane or arene carbon-hydrogen bond. While phosphines have been shown to be rather unexceptional ligands for organoactinides, the reaction of trialkylphosphites with the organoactinide hydrides {M[(CH₃)₅C₅]₂H₂}₂, M = Th, U takes a different course. In the case of P(OCH₃)₃, quantitative demethoxylation of the phosphite occurs under mild conditions to yield μ-phosphinidine complexes of the type {M[(CH₃)₅C₅]₂(OCH₃)}PH.