First characterization of an uranium(III) complex with a carbonyl-containing ligand: Syntheses and X-ray crystal structures of the homoleptic dimethylformamide complexes [M(dmf)n]I3 (M = Ce, Nd and n = 8; M = La, Ce, U and n = 9)

Solutions of the trivalent iodides LnI3 and [UI3(py)4] in dimethylformamide (dmf) deposited crystals of the tricationic species [M(dmf)n]I3 (M = Ce (1), Nd (2) and n = 8; M = La (3), Ce (4), U (5) and n = 9). The dmf ligands are labile and easily removed under vacuum affording solid samples of [MI3(dmf)n] compounds with varying numbers of coordinated dmf molecules (n = 2–6). The uranium derivative was oxidized into [U(dmf)9]I4 in dmf at 110 °C. X-ray crystal structures of complexes 1–5 show the differences between the U–O and Ln–O distances to reflect the variation in the ionic radii of the metals, demonstrating the similar nature of the [M]–OC interaction in these series of 4f- and 5f-elements.

Graphical abstractCrystals of the title compounds were deposited from dmf solutions of LnI3 (Ln = La, Ce, Nd) and [UI3(py)4]. The crystal structures show the differences in the M–O distances to reflect the variation in the ionic radii of the metals.Figure optionsDownload full-size imageDownload as PowerPoint slide