Cationic Organozirconium and Organohafnium Complexes

Solvent-Free Lanthanoid Complexes Derived From Chelation-Supported Organoamide Ligands

“…In fact the opposite is observed. However, the cis NϪLnϪN angles are not unreasonably narrow and still compare well with those of fac-[Ln(enЈ) 3 ]. [27] Therefore the variation in angles is possibly associated with differences in the crystal packing required to accommodate solvent molecules.…”

“…A range of [Ln(L) 3 ] complexes [L ϭ L 1 , Ln ϭ Yb (1a), Er (1b), Sm (1c), Pr (1d), Nd (1e); L ϭ L 2 , Ln ϭ Yb (2a), Y (2b), Sm (2c), Nd (2d), La (2e)] were prepared by treatment of LnCl 3 with three molar equivalents of LiL as the isolated [Li(L 1 )(OEt 2 )] 2 [Scheme 1 (i)] or generated in situ from the reaction of LH with nBuLi in THF [Scheme 1 (ii)]. The crystalline complexes [Ln(L 1 ) 3 ] [Ln ϭ Yb (1a), Er (1b), Sm (1c), Pr (1d), Nd (1e)] were isolated from hexane in good yield after removal of the precipitated LiCl.…”

“…Sect.). In the mass spectra of 1c and 1e, the highest metalcontaining fragment was attributable to the parent ion [Ln(L 1 ) 3 ] ϩ ; loss of the groups SiMe 3 and OMe or OPh from the molecular ion was observed for 1b, 2a·(PhMe) or 2a·(C 5 H 9 Me). The mass fragment [Ln(L 1 ) 2 ] ϩ was observed in the spectra of all three complexes, as well as the metalfree fragment [L 1 H] ϩ .…”

“…The visible/near infrared spectrum of 5a·(PhMe) 2 showed absorptions characteristic of Nd 3ϩ . [31] Mass spectra identified a bimolecular species to be present for 3aϪ3e with the highest-mass fragment, except for ytterbium, being the ion [Ln 2 (enЈ) 3 Cl 2 ] ϩ . (For the heavier ytterbium metal only the fragment [Yb 2 (enЈ) 2 Cl 2 ] ϩ was detected due to limitations in the accessible mass spectrum range.)…”

“…Encouragement for this idea came from the observation that N,N-dimethyl-NЈ-trimethylsilylethane-1,2-diaminate (enЈ) gave not only the homoleptic complexes [Ln(enЈ) 3 ] (Ln ϭ Lu, Er, Eu, Sm, Nd, La) but also a single example of a heteroleptic derivative [Er(enЈ) 2 Cl]. [27] We now report a study of the use of the two new mixed N,O-donor bidentate amide ligands N-(2-methoxyphenyl)-N-(trimethylsilyl)amide (L 1 ) [28] and N-(2-phenoxyphenyl)-N-(trimethylsilyl)amide (L 2 ) [28,29] for preparing [Ln(L) 3 ] and [Ln(L) 2 Cl] complexes, and extend the enЈ heteroleptic series to lanthanoids other than Er. Previous studies on lanthanoid complexes containing the L 1 and L 2 ligands have shown them to be capable of supporting organo-oxo heteroleptic complexes viz.…”