Examples of the ability of the donor-functionalised amide ligands N-(2-methoxyphenyl)-N-(trimethylsilyl)amide (L1) and N-(2-phenoxyphenyl)-N-(trimethylsilyl)amide (L2) to support mixed-ligand lanthanoid complexes of the type [Ln(L)2A] or [Ln(L)AB] are described. Reaction of [Yb(OAr)3] (Ar = C6H3But2-2,6) with two equivalents of [Li(L2)]n in hexane gave hexane-soluble, monomeric and five-coordinate [Yb(L2)2(OAr)] (1) in high yield. Attempted preparation of an analogous [Yb(L1)2(MeCp)] complex by reaction of [Yb(MeCp)Cl2(thf)] with [Li(L1)(OEt2)]2 (with a Yb ∶ Li ratio of 1 ∶ 2) in thf instead gave the known [Yb(L1)2(μ-Cl)]2 (2). In contrast, the stable complexes [Yb(MeCp)(L1)(μ-Cl)]2 (3) and [Yb(MeCp)(L2)(μ-Cl)]2 (4) were readily obtained from 1 ∶ 1 (Li ∶ Yb) reaction of [Yb(MeCp)Cl2(thf)] with [Li(L1)(OEt2)]2 or [Li(L2)(dme)] in thf. The complexes 1, 3 and 4 have been characterised by X-ray structure determination.
- Cyclopentadienyl and related alkenyl ligands
- P, N, S, Se, O, Te, Si-containing ligands
- Structural studies