Actinides: Amido Complexes

AbstractThis article reviews progress in actinide amido chemistry, highlighting the role of amido anions as constituents of robust supporting ligands and as reactive ligands. The synthesis, structures, and reactivity of homoleptic actinide complexes in oxidation states III–VI are initially reviewed. Reactivity developed using an ancillary ligand set composed of three bulky monodentate amido anions is then discussed, followed by the chemistry of N(CH2CH2NSiR3)3(TrenX) and HC(SiMe2NAr)3(TsX) ligands, which feature three amido anions within a multidentate ligand framework. These trisamido ligand platforms have been used to develop a remarkable breadth of actinide chemistry, including terminal UE and U(η2‐E2) linkages (E = S, Se, or Te), the first terminal nitrido complexes of uranium(V) and (VI), a unique nitrido analogue of the uranyl anion [NUO]+, the only terminal PH and AsH complexes of a d‐ or f‐element, and the first metal complex containing the elusive As2H2molecule. Complexes of tridentate pincer ligands are also described, with a focus on organometallic derivatives, as are bidentate ligands, including redox‐active NN and NO donors. Actinide complexes of polypyrrolyl ligands containing up to eight nitrogen donors are then outlined, including a neptunium(II) complex and a highly reducing thorium(II) synthetic equivalent. Furthermore, bimetallic “Pacman”‐style uranyl complexes are reviewed, providing examples of acis‐uranyl linkage, as well as reduction and functionalization of the normally inert uranyl dication. Finally, additional facets of amido ligand reactivity are discussed, including alternative pathways to synthesize actinide amido complexes and the role of actinide–amido complexes in catalysis.