Synthesis and comparison of iso-structural f-block metal complexes (Ce, U, Np, Pu) featuring η6-arene interactions

• Published in: Chemical science (Cambridge) 2023-07, Vol.14 (27), p.7438-7446
• Main Authors: Murillo, Jesse, Goodwin, Conrad A P, Stevens, Lauren, tier, Skye, Gaunt, Andrew J, Scott, Brian L
• Format: Article
• Language: English
• Subjects: Actinides; Cerium; Chemistry; Congeners; Coordination compounds; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Neptunium; Plutonium; Uranium
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/d3sc02194g

Reaction of the terphenyl bis(anilide) ligand [{K(DME)2}2LAr] (LAr = {C6H4[(2,6-iPr2C6H3)NC6H4]2}2−) with trivalent chloride “MCl3” salts (M = Ce, U, Np) yields two distinct products; neutral LArM(Cl)(THF) (1M) (M = Np, Ce), and the “-ate” complexes [K(DME)2][(LAr)Np(Cl)2] (2Np) or ([LArM(Cl)2(μ-K(X)2)])∞ (2Ce, 2U) (M = Ce, U) (X = DME or Et2O) (2M). Alternatively, analogous reactions with the iodide [MI3(THF)4] salts provide access to the neutral compounds LArM(I)(THF) (3M) (M = Ce, U, Np, Pu). All complexes exhibit close arene contacts suggestive of η6-interactions with the central arene ring of the terphenyl backbone, with 3M comprising the first structurally characterized Pu η6-arene moiety. Notably, the metal–arene bond metrics diverge from the predicted trends of metal–carbon interactions based on ionic radii, with the uranium complexes exhibiting the shortest M–Ccentroid distance in all cases. Overall, the data presents a systematic study of f-element M-η6-arene complexes across the early actinides U, Np, Pu, and comparison to cerium congeners.