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DOI: 10.1039/A700113D (Paper) Reference Section for: J. Chem. Soc., Dalton Trans., 1997, 1945-1952

Synthesis, characterisation and alkylation reactions of lanthanide β-diketiminates; crystal structures of [[upper bond 1 start]Nd(L–L[upper bond 1 end])2Cl] and [[upper bond 1 start]Ce(L–L[upper bond 1 end])(CHR2)2] [L–L = N(R)C(Ph)C(H)C(Ph)NR, R = SiMe3][hair space]

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Peter B. Hitchcock, Michael F. Lappert and Shun Tian

Abstract

Treatment of two equivalents of the sodium β-diketiminate Na(L–L) 1 with a lanthanide metal(III) chloride, LnCl3, yielded the mononuclear complex [[upper bond 1 start]Ln(L–L[upper bond 1 end])2Cl] (Ln = Ce 3, Pr, Nd 5, Sm or Yb); similarly, two equivalents of 1 with TmI3 gave [[upper bond 1 start]Tm(L–L[upper bond 1 end])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 [[upper bond 1 start]Ce(L–L[upper bond 1 end])(CHR2)2] 9. Lanthanide metal(III) β-diketiminates [Ln(L–L)2(thf)2] (Ln = Sm or Yb) or [[upper bond 1 start]Yb(L–L[upper bond 1 end])2] and [[upper bond 1 start]Yb(L–L[upper bond 1 end]′)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 [[upper bond 1 start]Yb(L–L[upper bond 1 end]′)2] 13 two isomers were present. X-Ray diffraction data for [[upper bond 1 start]NdL–L[upper bond 1 end])2Cl] 5 and [[upper bond 1 start]Ce(L–L[upper bond 1 end])(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.

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