Chloro(p-chloroanilido-N)bis(η⁵-pentamethylcyclopentadienyl)uranium(IV)

Synthesis, structure, spectroscopy and redox energetics of a series of uranium(IV) mixed-ligand metallocene complexes

“…Both complexes 2 and 6 feature a bent-metallocene framework with the amide and chloride (for 2) or isocyanate (for 6) ligands contained within the metallocene wedge. For (C 5 Me 5 ) 2 U[N(SiMe 3 ) 2 ](Cl) (2), the U(1)-Cl(1) (2.606(3) Å ) and U(1)-N(1) (2.268(4) Å ) bond lengths are typical of U IV -Cl [3,5,33,34] and U IV -N amide [5,8,9,[34][35][36][37] bond lengths. [32].…”

“…Both complexes 9 and 10 feature a bent-metallocene framework with the amide and chloride (for 9) or azide (for 10) ligands contained within the metallocene wedge. The structure of (C 5 Me 5 ) 2 U[N(Ph)-(SiMe 3 )](Cl) (9) is similar to that of (C 5 For benzyl complexes, two parameters have been defined to quantify the benzyl ligand-to-metal interaction,…”

“…As summarized in Scheme 1, reaction of the trivalent uranium amide complex (C 5 Me 5 ) 2 U[N(SiMe 3 ) 2 ] [29] with various Cu, Ag, and Au reagents afforded the series of related complexes (C 5 Me 5 ) 2 U[N(SiMe 3 ) 2 ](X) (X = F (1), Cl (2), Br (3), I (4), N 3 (5), and NCO (6)). Specifically, the U IV amide-halide complexes (C 5 (4) were obtained by oxidation of (C 5 Me 5 ) 2 U[N(SiMe 3 ) 2 ] using an excess (5 equiv.) of the appropriate Cu halide salt.…”

“…There is a linear correlation between the chemical shift values of the C 5 Me 5 ligand protons in the 1 H NMR spectra and the U IV / U III reduction potentials of the (C 5 Me 5 ) 2 U[N(SiMe 3 ) 2 ](X) complexes, suggesting that there is a common origin, that is overall s-/p-donation from the ancillary (X) ligand to the metal, contributing to both observables. Optical spectroscopy of the series of complexes 1-6 is dominated by the (C 5 During the course of these studies, it became evident that the amide mixed-ligand framework provided the opportunity to examine a new homologous structural series from which we can draw new inferences regarding uranium metal-ligand bonding. This falls within the broader context of our continuing efforts to map out trends in the redox energetics and electronic structure of metallocene complexes of the early actinides and correlate these trends with structural chemistry [12][13][14][15][16].…”

“…A series of uranium(IV) mixed-ligand amide-halide/pseudohalide complexes (C 5 Me 5 ) 2 U[N(SiMe 3 ) 2 ](X) (X = F (1), Cl (2), Br (3), I (4), N 3 (5), NCO (6)), (C 5 Me 5 ) 2 U(NPh 2 )(X) (X = Cl (7), N 3 (8)), and (C 5 Me 5 ) 2 U[N(Ph)(SiMe 3 )](X) (X = Cl (9), N 3 (10)) have been prepared by one electron oxidation of the corresponding uranium(III) amide precursors using either copper halides, silver isocyanate, or triphenylphosphine gold(I)azide. Agostic UÁ Á ÁH-C interactions and h 3 -(N,C,C 0 ) coordination are observed for these complexes in both the solid-state and solution.…”