The chloroamide complexes U (NEt2)(4-x)Cl-x (x = 1, 2) were obtained by com
proportionation of UCl4 and U(NEt2)(4). The novel protonolysis reaction of
a metal-amide bond with an acidic ammonium salt proved to be an efficient a
nd convenient synthesis of cationic compounds. Thus were synthesized a seri
es of metallo-organic and organometallic uranium cations in the oxidation s
tates +3, +4, +5. The cationic amide compounds were valuable precursors of
new derivatives, as they reacted with anionic reagents, acidic substrates a
nd unsaturated molecules to give the addition, substitution and insertion p
roducts; in particular, such reactions were useful for the synthesis of mon
ocyclooctatetraene uranium compounds. The dialkyl amide ligand was found ab
le to stabilize the +5 oxidation state of uranium; neutral and cationic ura
nium(Ti) complexes were obtained by oxidation of their corresponding anioni
c and neutral U(IV) precursors. (C) 1998 Elsevier Science S.A. All rights r
eserved.