Uranium amides as precursors to cationic and/or pentavalent compounds

The uranium chloroamide complexes [U(NEt2)nCl4-n] (n=1, 2) were isolated from the comproportionation reactions of [U(NEt2)4] and UCl4. The protonolysis reaction of the M-NR2 bond (M=Ti, Zr, Hf, U; R=Me, Et, SiMe3) with the ammonium salt NHR3'BPh4 (R'=Et, Me) constitutes an efficient and practical route to cationic complexes. Thus were prepared a series of organometallic uranium cations in the +3, +4 and +5 oxidation states. The reactions of these cationic compounds with nucleophiles, proton acidic substrates and unsaturated molecules have been developed. The dialkylamide ligand was useful to stabilize unique examples of neutral and cationic complexes of uranium in the +5 oxidation state. (orig.)