Reactivity of dicyclopentadienylbis(diethylamido)uranium(IV). Reactions with carboxylic and thiocarboxylic acids

Article abstract of DOI:10.1021/ic50222a023

The reaction of Cp₂U(NEt₂)₂ with carboxylic and thiocarboxylic acids produced complexes of the type Cp₂U(XYCR)₂ (X = Y = O, R = Me, Ph, t-Bu; X = O, Y = S, R = Me, Ph). Solubility properties of the acetate and benzoate derivatives indicate polymeric behavior, whereas molecular weight measurements show that the pivalate complex is dimeric and the thiobenzoate compound is monomeric. The infrared spectra of all the complexes indicate η⁵-cyclopentadienyl bonding and bidentate, chelating and/or bridging, carboxylate moieties. Assuming that the monomeric Cp₂U(OSCPh)₂ exhibits the expected pseudo-cis-octahedral geometry, it is shown that the variable-temperature ¹H NMR spectra of the molecule is only compatible with a combination of metal-centered rearrangement and C-Ph bond rotation. The simple and temperature-invariant nature of the spectrum for Cp₂U(O₂CCMe₃)₂ implies a symmetrical dimeric structure, and a possibility for this is proposed.