Peter B. Hitchcock, Michael F. Lappert and Shun Tian
Treatment of two equivalents of the sodium β-diketiminate
Na(L–L) 1 with a lanthanide metal(III) chloride,
LnCl3, yielded the mononuclear complex
[Ln(L–L
)2Cl] (Ln = Ce 3,
Pr, Nd 5, Sm or Yb); similarly, two equivalents of 1 with
TmI3 gave [
Tm(L–L
)2I]
[L–L = N(R)C(Ph)C(H)C(Ph)NR;
R = SiMe3]. When 3 was mixed with either one or
two equivalents of Li(CHR2) in diethyl ether, the only new
cerium-contaning product was
[
Ce(L–L
)(CHR2)2] 9.
Lanthanide metal(III) β-diketiminates
[Ln(L–L)2(thf)2] (Ln = Sm or
Yb) or [
Yb(L–L
)2] and
[
Yb(L–L
′)2] 13 were obtained from
[LnI2(thf)2] (Ln = Sm or Yb) and
K(L–L) in thf, or YbI2 and K(L–L) or
K(L–L′) in Et2O
[L–L′ = N(R)C(Ph)C(H)C(But)NR;
thf = tetrahydrofuran]. The various lanthanide metal
β-diketiminates were characterised by elemental analysis, mass
spectrometry and multinuclear NMR spectra. The last of these indicated
(by variable-temperature experiments) that for
[
Yb(L–L
′)2] 13 two isomers were
present. X-Ray diffraction data for
[
NdL–L
)2Cl] 5 and
[
Ce(L–L
)(CHR2)2] 9 revealed
that for each of these crystalline mononuclear complexes the metal atom
is well shielded, due to the extremely sterically demanding monoanionic
[L–L]- ligand, which has some η5
character in these molecules.