Cyclopentadienyl‐Free Organolanthanide Chemistry

Abstract

During the past ten years the organometallic chemistry of the lanthanides has witnessed enormous growth. One of the main reasons for this development was the finding that lanthanide metallocenes can exhibit an unusually high catalytic activity. Considerable advances have also been achieved in the chemistry of organolanthanide complexes that are not stabilized by cyclopentadienyl ligands. For example, the successful synthesis of the first unsolvated homoleptic trialkyllanthanides, [Ln{CH(SiMe3)2}3], has recently been reported. Anionic allyl complexes of the lanthanides show promising catalytic properties and cyclooctatetraene complexes of these elements are also under active investigation. This review is intended to provide an overview of this rapidly developing area of research.

Scandium, Yttrium & The Lanthanides: Organometallic ChemistryBased in part on the article Scandium, Yttrium & The Lanthanides: Organometallic Chemistry by R. D. Köhn, G. Kociok‐Köhn, & H. Schumann which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

“…The crystal structure of [Li(TMEDA)] 3 [LnMe 6 ] (Ln = Ho, Er) and [Li(DME)] 3 [LuMe 6 ] shows an octahedral LnMe 6 arrangement with Me bridges to the Li atoms ( Figure 1). Alkylation of (L)LnCl 3 (Ln = Sc, Y; L = 1,4,7-trimethyl-1,4,7-triazacyclononane) with MeLi in THF gives the corresponding species (L)Ln(CH 3 ) 3 , and the reaction of LuCl 3 with NaCp* and LiMe in THF in the presence of TMEDA yields [Li(TMEDA) 2 ][Cp*LuMe 3 ], showing the Lu atom tetrahedrally coordinated by the Cp* ring and the three Me groups.…”

“…The reactions of LnCl 3 (Ln = Y, La, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) with MeLi in Et 2 O in the presence of TMEDA or DME yields ate complexes [Li(L)] 3 [LnMe 6 ] (L = TMEDA, DME) (equation 1). The crystal structure of [Li(TMEDA)] 3 [LnMe 6 ] (Ln = Ho, Er) and [Li(DME)] 3 [LuMe 6 ] shows an octahedral LnMe 6 arrangement with Me bridges to the Li atoms ( Figure 1).…”

“…13 The tris(trimethylsilylmethyl)scandium and -yttrium derivatives are thermally unstable. The bulky PhMe 2 SiCH 2 ligand allows the isolation of thermally more robust analogues Ln(CH 2 SiMe 2 Ph) 3 (THF) 2 (M = Sc, Y).…”

“…Yb(CH 2 SiMe 3 ) 3 (THF) 2 and the related neopentyl derivative Yb(CH 2 t Bu) 3 (THF) 2 are formed by the reaction of ytterbium metal with ICH 2 SiMe 3 or neopentyl iodide in THF. 12 X-ray structural analyses of the Sm, Er, Yb, and Lu derivatives show the Sm atom in a fac-octahedral coordination and the heavier lanthanides Er, Yb, and Lu trigonal bipyramidally coordinated with three alkyl ligands in equatorial and two THF molecules in axial positions (equation 2).…”

[N-(2-Anilinoethyl)-N′-(trimethylsilyl)benzenecarboximidamidato-κ3 N,N′,N′′](benzonitrile-κN)trichloridozirconium(IV)

“…Nitrogen-based ligands have attracted much interest in organometallic chemistry and catalysis chemistry (Edelmann, 1995;Mack & Eisen, 1996). As the closest relatives of nitrogen-based ligands, amidinate ligands have attracted considerable attention due to their relatively simple synthesis and easy modification of steric and electronic requirements by varying the substituents on the nitrogen atom.…”