Aminolysis of Lithium/Yttrium Bimetallic Alkyls including the Solid‐State Structure of a Europium(II) n‐Butyl Compound

Abstract

Using previously established salt‐metathesis procedures at low temperature, heterobimetallic ate complexes Li6EuII(n‐Bu)8(thf)6 and Li3YIII(i‐Bu)6(thf)4 could be synthesized and their solid‐state structures analyzed by X‐ray diffraction. Recently described complex Li3Y(n‐Bu)6(thf)4 was probed as a precursor in protonolyses with various amines, revealing distinct reaction pathways. Identified products comprise homoleptic amide Y[HNC6H3(mes)2‐2,6]3 (mes=C6H2Me3‐2,4,6), heteroleptic C−H‐bond activated Li3Y(n‐Bu)2[N(SiMe2CH2)(C6H3‐Me2‐3,5)]2(thf)5, and mixed amido/imido complex [LiY2(HNSiPh3)4(NSiPh3)2][Li(thf)2(OEt2)2].

Divalent Lanthanide Tetraisobutylaluminates: Reactivity and Living Isoprene Polymerization

“…[21] Structural motifs observed within these isobutylaluminate complexes are shown in Scheme 1. [22] Herein, we wish to present the first crystal structures of homoleptic metal tetraisobutylaluminates. The reactivity of compounds [Ln(AliBu 4 ) 2 ] (Ln = Sm, Eu, Yb) toward oxidizing and cationizing reagents is studied in detail.…”

“…characterized alkoxy/isobutyl heteroaluminates [(HO i Pr)Sm( μ ‐O i Pr){( μ ‐O i Pr) 2 Al( i Bu)(O i Pr)}] 2 and [(THF) 2 Sm(O t Bu) 2 {( μ ‐O t Bu) 2 Al i Bu 2 }] as the only ancillary ligand‐free complexes, accessed by reacting [Sm{N(SiMe 3 ) 2 } 3 ] with Al i Bu 3 in the presence of 6 equiv of isopropyl alcohol and tert ‐butanol, respectively [21] . Structural motifs observed within these isobutylaluminate complexes are shown in Scheme 1 [22] …”

Mixed Methyl/Chlorido Yttrium(III) Complexes Supported by a Neutral Tridentate N-Donor Ligand

“…As mentioned in the Introduction, mixed alkyl/chlorido rare-earth-metal complexes are active catalysts, e.g., in 1,3-diene polymerization. − Unfortunately, discrete heteroleptic complexes of the type Ln­(alkyl) x (halogenido) y are not accessible through salt metathesis of activated rare-earth-metal chlorides and alkyllithium reagents. Instead, the formation of mixtures of ate complexes (e.g., hexaalkyl) and the corresponding lithium halide prevails. ,, The sterically demanding Me 3 TACN ligand has shown to kinetically stabilize complexes and inhibit rapid ligand redistribution. For example, the group of Flood reported the isolation of mixed ligand compounds (Me 3 TACN)­RhMe 3– x X x ( x = 1, 2; X = Cl, OTf, BF 4 ) by reacting (Me 3 TACN)­RhMe 3 with the appropriate amount of the corresponding acid HX.…”

Rare-earth-metal trimethylsilylmethyl ate complexes

“…Employing our recently established low-temperature syntheses and crystallization techniques, giving access to the alkyl ate complexes Li 3 Lu( n -Bu) 6 (thf) 4 , Li 2 Ln( n -Bu) 5 (tmeda) 2 (Ln = Ce, Lu), [Ce( t -Bu) 4 ][Li(thf) 4 ], Li 6 Eu( n -Bu) 8 (thf) 6 , and Li 3 Y( i -Bu) 6 (thf) 4 , the reaction system LaCl 3 (thf)/3LiCH 2 SiMe 3 was investigated similarly. 23 When using a solvent mixture of THF and n -hexane, no reaction took place at −40 °C. However, switching to a mixture of THF and diethyl ether accomplished a slow reaction which led to the isolation of crystalline [Li(thf) 4 ][La(CH 2 SiMe 3 ) 4 (thf)] ( 3 ) (Scheme 3 and Fig.…”