Monocyclooctatetraene uranium amide compounds in the+ 4 and+ 5 oxidation states
Résumé
The compounds M[U(cot)(NE$t_2$$)_3$] 1 (cot =$\eta$-$C_{8}$$H_{8}$, M = Li or K) were prepared by (a) reaction of [U(NE$t_2$$)_4$] or [U(NE$t_2$$)_3$][B$Ph_{4}$] with $K_{2}$ (cot), (b) treatment of U$Cl_{4}$ with LiNE$t_2$. and $K_{2}$ (cot) and (c) reaction of [U(cot$)_{2}$] with LiNE$t_2$. The compound [U(cot)( NE$t_2$$)_2$(thf)] 2 (thf = tetrahydrofuran) was synthesized by treating [U(NE$t_2$$)_2$$Cl_{2}$] with K2(cot). Uranium(V) compounds were obtained by oxidation of 1 and 2. Treatment of 1 with Tl B$Ph_{4}$ afforded [U(cot)( NE$t_2$$)_3$] which was tranformed into [U(cot)(OPri)3] by alcoholysis. Complex 2 reacted with AgB$Ph_{4}$ or Tl(cp)(cp=$\eta$-$C_{5}$$H_{5}$) to give [U(cot)( NE$t_2$$)_2$ (thf)][B$Ph_{4}$] and [U(cot)(cp)( NE$t_2$$)_2$] respectively, the crystal structure of the first of which has been determined.