名称:
Synthesis of Dianionic β-Diketiminate Lanthanide Amides L′LnN(SiMe3)2(THF) by Deprotonation of the β-Diketiminate Ligand L (L = {[(2,6-iPr2C6H3)NC(CH3)]2CH}−) and the Transformation with [HNEt3][BPh4] to the Cationic Samarium Amide [LSmN(SiMe3)2][BPh4]
摘要:
Reaction of beta-diketiminate lanthanide dichlorides LLnCl(2)(THF)(2) (L = {[(2,6-iPr(2)C(6)H(3))NC(CH3)](2)CH}(-)) with 2 equiv of NaN(SiMe3)(2) in toluene afforded lanthanide amide complexes supported by a dianionic beta-diketiminate ligand L', L'LnN(SiMe3)(2)(THF) (L' = {(2,6-iPr(2)C(6)H(3))NC(CH2)CHC(CH3)N(2,6-iPr(2)C(6)H(3))}(2-), Ln = Yb (1), Y (2), Gd (3), Sm (4)), in moderate yields via deprotonation of L. Addition of a small amount of THF led to an increase of the yields of 1-4. Lanthanide metals have a great influence on the deprotonation of L. The same reaction with LNdCl2(THF)(2) did not afford the analogous complex L'NdN(SiMe3)(2)(THF), but the normal diamide complex LNd[N(SiMe3)(2)](2) (5) was isolated instead. The metathesis reaction of the triply bridged dichlorides of Sm, LSmCl(mu-Cl)(3)SmL(THF), with 2 equiv of NaN(SiMe3)(2) yielded the diamide complexes LSm[N(SiMe3)(2)](2) in toluene, while complex 4 was formed instead in a mixture of toluene and THF. In contrast, the same reactions with LYbCl(mu-Cl)(3)YbL(THF) either in toluene or in a mixture of toluene and THF both afforded 1. Treatment of 4 with [HNEt3][BPh4] in THF at room temperature gave the novel cationic Sm beta-diketiminate amide complex [LSmN(SiMe3)(2)(THF)(2)][BPh4] (7) in good yield. Complexes 1-5 and 7 have been confirmed by single-crystal X-ray structural analyses. The mechanism of deprotonation of L was discussed.