Rare-Earth-Metal Allyl Complexes Supported by the [2-(N,N-Dimethylamino)ethyl]tetramethylcyclopentadienyl Ligand: Structural Characterization, Reactivity, and Isoprene Polymerization

Abstract

Rare-earth-metal half-sandwich allyl complexes bearing an amino-functionalized cyclopentadienyl ligand (Cp NMe2 = 1-[2-(N,N-dimethylamino)ethyl]-2,3,4,5-tetramethylcyclopentadienyl) were synthesized in a two-step saltmetathesis reaction. Treatment of LnCl 3 (THF) x with LiCp NMe2 , followed by an in situ reaction with the Grignard reagent C 3 H 5 MgCl, generated the bis(allyl) half-sandwich complexes Cp NMe2 Ln(η 3 -C 3 H 5 ) 2 only for the smaller rare-earth metals (Ln = Y, Ho, Lu) in good yields (82−88%). In case of the larger neodymium, the dimeric mono(allyl) chlorido half-sandwich complex [Cp NMe2

Rare‐Earth‐Metal Pentadienyl Half‐Sandwich and Sandwich Tetramethylaluminates–Synthesis, Structure, Reactivity, and Performance in Isoprene Polymerization

“…Representative polymerization reactions were also run with the open sandwich complexes 4 Y and 4 Lu (Table S5). Only a few examples of such “monoalkyl” species were previously shown to be capable of polymerizing 1,3‐dienes . These rare examples are limited to the dimeric complexes [(C 5 Me 4 ) 2 Ln( μ ‐Me) 2 AlMe 2 ] 2 and [(C 5 Me 4 )SiMe 2 P(Cy)Ln(CH 2 SiMe 3 )] 2 (Ln=Y, Lu; Cy=cyclohexyl), which however require careful activation with one equivalent of co‐catalyst per dimeric complex.…”

Recent Advances in Rare Earth Complexes Bearing Allyl Ligands and Their Reactivity towards Conjugated Dienes and Styrene Polymerization

“…98% cis-units). [27]. The reaction was conducted in two steps by first reacting RECl 3 (THF) x with Cp NMe2 Li at room temperature, and then adding two equivalents of the Grignard reagent C 3 H 5 MgCl.…”

Yttrium Siloxide Complexes Bearing Terminal Methyl Ligands: Molecular Models for Ln−CH3 Terminated Silica Surfaces

“…[16] In this respect, we have previously presented rare-earth metal (neodymium) alkyl-grafted silica as highly efficient catalysts for the fabrication of 1,4-cis polyisoprene. [17,18] Our group has intensively investigated the related rare-earth metal alkylaluminates [19] and their performance as catalysts in isoprenep olymerization, [20] also tackling heterogenization issues. [17,18] Our group has intensively investigated the related rare-earth metal alkylaluminates [19] and their performance as catalysts in isoprenep olymerization, [20] also tackling heterogenization issues.…”

“…[10a] Neodymium-basedZ iegler Mischkatalysatoren,c omposed of easy-to-handle Nd III carboxylate or alkoxidec omplexes and hazardouso rganoaluminum and/or halide sources, are routinely employed by the rubber industry. [17,18] Our group has intensively investigated the related rare-earth metal alkylaluminates [19] and their performance as catalysts in isoprenep olymerization, [20] also tackling heterogenization issues. [10a,d,h] Heterogeneousr are-earth metal catalysts for the polymerization of 1,3-butadiene were explored as early as 1985.…”