Synthesis and structural studies of heteroleptic complexes of ytterbium(III) involving aryloxy- or alkoxy- and cyclopentadienyl ligands

Article abstract of DOI:10.1016/j.ica.2003.11.009

Treatment of tris-cyclopentadienyl-ytterbium in thf with one equivalent of 2,6-di(tert-butyl)phenol, N,N-dimethyl-2-aminoethanol or N,N-diethyl-2- aminoethanol resulted in substitution of one cyclopentadienyl ligand and formation of [YbCp₂(O-C₆H₃^tBu-2,6) (thf)] (1), [{YbCp₂(μ-OCH₂CH₂NMe ₂)}₂] (2) or [{YbCp₂(μ-OCH ₂CH₂NEt₂)}₂]·(thf) ₂ (3), respectively. All compounds were characterised by spectroscopic and X-ray crystallographic techniques, the latter two also being studied by variable temperature ¹H NMR spectroscopy. Compound (1) is mononuclear with the Yb centre bound by two η⁵-cyclopentadienyl ligands one O-bound thf and an O-bound phenoxy ligand. Compounds (2) and (3) are centrosymmetric dimers with the Yb centre bound by two η⁵- cyclopentadienyl ligands, while the bidentate ligands chelate the metal centre and also bridge to the adjacent Yb through the alkoxy oxygen atom. Variable temperature ¹H NMR studies on compounds (2) and (3) show a solution-state equilibrium between the dimeric solid-state structure and one with the nitrogen atoms non-bound to Yb.