Synthesis and Structures of the C₅Me₄SiMe₃‐Supported Polyhydride Complexes over the Full Size Range of the Rare Earth Series

Abstract

The acid-base reaction of [Ln(CH(2)SiMe(3))(3)(thf)(2)] with Cp'H gave the corresponding half-sandwich rare earth dialkyl complexes [(Cp')Ln(CH(2)SiMe(3))(2)(thf)] (1-Ln: Ln=Sc, Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu; Cp'=C(5)Me(4)SiMe(3)) in 62-90% isolated yields. X-ray crystallographic studies revealed that all of these complexes adopt a similar overall structure, in spite of large difference in metal-ion size. In most cases, the hydrogenolysis of the dialkyl complexes in toluene gave the tetranuclear octahydride complexes [{(Cp')Ln(μ-H)(2)}(4)(thf)(x)] (2-Ln: Ln=Sc, x=0; Y, x=1; Er, x=1; Tm, x=1; Gd, x=1; Dy, x=1; Ho, x=1) as the only isolable product. However, in the case of Lu, a trinuclear pentahydride [(Cp')(2)Lu(3)(μ-H)(5)(μ-CH(2)SiMe(2)C(5)Me(4))(thf)(2)] (3), in which the C-H activation of a methyl group of the Me(3)Si unit on a Cp' ligand took place, was obtained as a major product (66% yield), in addition to the tetranuclear octahydride [{(Cp')Lu(μ-H)(2)}(4)(thf)] (2-Lu, 34%). The use of hexane instead of toluene as a solvent for the hydrogenolysis of 1-Lu led to formation of 2-Lu as a major product (85%), while a similar reaction in THF yielded 3 predominantly (90%). The tetranuclear octahydride complexes of early (larger) lanthanide metals [{Cp'Ln(μ-H)(2)}(4)(thf)(2)] (2, Ln=La, Ce, Pr, Nd, Sm) were obtained in 38-57% isolated yields by hydrogenolysis of the bis(aminobenzyl) species [Cp'Ln(CH(2)C(6)H(4)NMe(2)-o)(2)], which were generated in-situ by reaction of [Ln(CH(2)C(6)H(4)NMe(2)-o)(3)] with one equivalent of Cp'H. X-ray crystallographic studies showed that the fine structures of these hydride clusters are dependent on the size of the metal ions.

Bis(alkyl) rare-earth complexes supported by a new tridentate amidinate ligand with a pendant diphenylphosphine oxide group. Synthesis, structures and catalytic activity in isoprene polymerization

“…27 The Er-C bond distances in 4 (2.401(3), 2.453(3) Å) are slightly elongated compared to the formerly described six-coordinate bis(alkyl) erbium complex [(C 5 Me 4 SiMe 3 )Er(CH 2 SiMe 3 ) 2 THF] (2.337(9), 2.381(1) Å). 28 The Ln-N bonds in 4 (2.413 (3) (32) 108.12 (7).…”

Rare‐Earth Metal Allyl and Hydrido Complexes Supported by an (NNNN)‐Type Macrocyclic Ligand: Synthesis, Structure, and Reactivity toward Biomass‐Derived Furanics

“…The solid-state structure of 3-La contains one molecule of benzene in the lattice and does not show any disorder, thereby allowing the location of all hydride positions ( Figure 7). Molecular lanthanum hydrides are rare, [18] 3-La representing the first example of structurally characterized non-cyclopentadienyl-supported lanthanum hydride. The solid-state structure shows a tetrameric La 4 H 8 core (Figure 8), which contains six m-bridging hydrides on the edges, one face-capped m 3 -hydride, and one m 4 -hydride in the center, coordinated tetrahedrally by four lanthanum atoms (q = 104-1168).…”

Yttrocene Chloride and Methyl Complexes with Variously Substituted Cyclopentadienyl Ligands: Synthesis, Characterization, and Reactivity toward Ethylene

“…One chloride ion is located at the center of the tetramer and determines the negative charge of this tetrameric cluster [Y1–Cl1 2.7880(4), Y2–Cl1 2.7712(5) Å]. The Y–Cg distances of 2.332(2) and 2.326(6) Å are slightly shorter than those observed in alkyl complexes of Y {e.g., 2.359(3) Å in [Y(η 5 ‐C 5 Me 4 SiMe 3 )Me(thf) 3 ] + [BPh 4 ] –[11] and 2.370(5) Å in [(η 5 ‐C 5 Me 4 SiMe 3 )Y(CH 2 SiMe 3 ) 2 (THF)]} . To the best of our knowledge, no such ionic, tetrameric, square‐planar structural motif with one chloride ion in the center of the tetramer has been reported in the literature.…”