Synthesis of a New Class of Compounds Containing a Ln−O−Al Arrangement and Their Reactions and Catalytic Properties

Synthesis of a new class of compounds containing a Ln−O−Al moiety has been accomplished
by the reaction of LAlOH(Me) (L = HC(CMeNAr)2, Ar = 2,6-iPr2C6H3) with a series of Cp3Ln compounds.
The terminal Al−OH group shows selective reactivity, and the complexes Cp2Ln(THF)−O−AlL(Me) (Ln =
Yb, 1; Er, 2; Dy, 3), Cp2Yb−O−AlL(Me) (4), and Cp3Ln(μ-OH)AlL(Me) (Ln = Er, 5; Dy, 6; Sm, 7) were
obtained. This allows further insight into the proton exchange process, and two different mechanisms,
intermolecular and intramolecular elimination of CpH, are proposed under different conditions. Complexes
1−4, 6, and 7 have been characterized by X-ray structural analyses which reveals a Ln−O−Al or Ln(μ-OH)Al core in these complexes. The obtuse Ln−O−Al angles fall in the range 151.9−169.8°. The reaction
of 1 or 4 with Me3SnF in toluene under refluxing conditions unexpectedly yielded the compounds [Cp2Yb(μ-OSnMe3)]2 (8) and LAl(Me)F (9). Reactions of LAlOH(Me) with the mono- and dicyclopentadienyl
complexes LYbCp(Cl) (10) and LYbCp2 (11) supported by the bulky β-diketiminate ligand were unsuccessful.
However, the reaction of LAl(OH)Me with LYbN(SiMe3)2Cl (12) containing a labile Yb−N bond leads to the
formation of LYbCl−O−AlL(Me) (13) under elimination of HN(SiMe3)2. Furthermore, complexes 1, 3, 4,
and 6 exhibit good catalytic activity for the polymerization of ε-caprolactone.

成功合成了一类含有Ln−O−Al基团的新型化合物，该合成是通过LAlOH(Me)（L = HC(CMeNAr)2，Ar = 2,6-iPr2C6H3）与一系列Cp3Ln化合物反应实现的。端位的Al−OH基团表现出选择性反应活性，并获得了Cp2Ln(THF)−O−AlL(Me)（Ln = Yb，1；Er，2；Dy，3）、Cp2Yb−O−AlL(Me)（4）和Cp3Ln(μ-OH)AlL(Me)（Ln = Er，5；Dy，6；Sm，7）等复合物。这为深入理解质子交换过程提供了新的视角，并提出了在不同条件下，CpH的分子间和分子内消除的两种不同机制。复合物1−4、6和7通过X射线结构分析进行了表征，揭示了这些复合物中存在Ln−O−Al或Ln(μ-OH)Al的核心。钝角Ln−O−Al的角度范围在151.9−169.8°之间。在回流条件下，1或4与Me3SnF在甲苯中的反应意外地生成了[Cp2Yb(μ-OSnMe3)]2（8）和LAl(Me)F（9）。LAlOH(Me)与由庞大的β-二酮亚胺配体支持的Cp单环戊二烯基和二环戊二烯基复合物LYbCp(Cl)（10）和LYbCp2（11）的反应未能成功。然而，LAl(OH)Me与含有易变的Yb−N键的LYbN(SiMe3)2Cl（12）的反应，在消除HN(SiMe3)2的过程中，导致了LYbCl−O−AlL(Me)（13）的形成。此外，复合物1、3、4和6对ε-己内酯的聚合表现出良好的催化活性。