Organometallic amides of uranium(IV) and thorium(IV) involving one, two, or three cyclopentadienyl ligands

Both U(NEt 2) 4 and Th(NEt 2) 4 can be treated stoichiometrically and kinetically controlled with cyclopentadiene so that the various products Cp n fM(NEt 2) 4-n (n = 2, 3, fM = U; n = 1, 2, 3, fM = Th) may be separately obtained in high yields. Cp 3UNEt 2 also reacts with an excess of HCp to give UCp 4. For the preparation of the complexes Cp 2U(NR 2) 2 (R = Et or Ph) and Cp 3UNEt 2, an alternative route, starting from UCl 4, TlCp and LiNEt 2 (KNPh 2) and from Cp 3UCl and LiNEt 2, respectively, has also been developed. The new complex CpU(NEt 2) 3 does not readily undergo ligand redistribution to give Cp 2U(NEt 2) 2 and U(NEt 2) 4, but it appears to react with another HCp molecule appreciably faster than does U(NEt 2) 4.